Tag Archives: proxy

How to add DNS filtering to your NAT instance with Squid

Post Syndicated from Nicolas Malaval original https://aws.amazon.com/blogs/security/how-to-add-dns-filtering-to-your-nat-instance-with-squid/

Note from September 4, 2019: We’ve updated this blog post, initially published on January 26, 2016. Major changes include: support of Amazon Linux 2, no longer having to compile Squid 3.5, and a high availability version of the solution across two availability zones.

Amazon Virtual Private Cloud (Amazon VPC) enables you to launch AWS resources on a virtual private network that you’ve defined. On an Amazon VPC, many people use network address translation (NAT) instances and NAT gateways to enable instances in a private subnet to initiate outbound traffic to the Internet, while preventing the instances from receiving inbound traffic initiated by someone on the Internet.

For security and compliance purposes, you might have to filter the requests initiated by these instances (also known as “egress filtering”). Using iptables rules, you could restrict outbound traffic with your NAT instance based on a predefined destination port or IP address. However, you might need to enforce more complex security policies, such as allowing requests to AWS endpoints only, or blocking fraudulent websites, which you can’t easily achieve by using iptables rules.

In this post, I discuss and give an example of how to use Squid, a leading open-source proxy, to implement a “transparent proxy” that can restrict both HTTP and HTTPS outbound traffic to a given set of Internet domains, while being fully transparent for instances in the private subnet.

The solution architecture

In this section, I present the architecture of the high availability NAT solution and explain how to configure Squid to filter traffic transparently. Later in this post, I’ll provide instructions about how to implement and test the solution.

The following diagram illustrates how the components in this process interact with each other. Squid Instance 1 intercepts HTTP/S requests sent by instances in Private Subnet 1, including the Testing Instance. Squid Instance 1 then initiates a connection with the destination host on behalf of the Testing Instance, which goes through the Internet gateway. This solution spans two Availability Zones, with Squid Instance 2 intercepting requests sent from the other Availability Zone. Note that you may adapt the solution to span additional Availability Zones.
 

Figure 1: The solution spans two Availability Zones

Figure 1: The solution spans two Availability Zones

Intercepting and filtering traffic

In each availability zone, the route table associated to the private subnet sends the outbound traffic to the Squid instance (see Route Tables for a NAT Device). Squid intercepts the requested domain, then applies the following filtering policy:

  • For HTTP requests, Squid retrieves the host header field included in all HTTP/1.1 request messages. This specifies the Internet host being requested.
  • For HTTPS requests, the HTTP traffic is encapsulated in a TLS connection between the instance in the private subnet and the remote host. Squid cannot retrieve the host header field because the header is encrypted. A feature called SslBump would allow Squid to decrypt the traffic, but this would not be transparent for the client because the certificate would be considered invalid in most cases. The feature I use instead, called SslPeekAndSplice, retrieves the Server Name Indication (SNI) from the TLS initiation. The SNI contains the requested Internet host. As a result, Squid can make filtering decisions without decrypting the HTTPS traffic.

Note 1: Some older client-side software stacks do not support SNI. Here are the minimum versions of some important stacks and programming languages that support SNI: Python 2.7.9 and 3.2, Java 7 JSSE, wget 1.14, OpenSSL 0.9.8j, cURL 7.18.1

Note 2: TLS 1.3 introduced an optional extension that allows the client to encrypt the SNI, which may prevent Squid from intercepting the requested domain.

The SslPeekAndSplice feature was introduced in Squid 3.5 and is implemented in the same Squid module as SslBump. To enable this module, Squid requires that you provide a certificate, though it will not be used to decode HTTPS traffic. The solution creates a certificate using OpenSSL.


mkdir /etc/squid/ssl
cd /etc/squid/ssl
openssl genrsa -out squid.key 4096
openssl req -new -key squid.key -out squid.csr -subj "/C=XX/ST=XX/L=squid/O=squid/CN=squid"
openssl x509 -req -days 3650 -in squid.csr -signkey squid.key -out squid.crt
cat squid.key squid.crt >> squid.pem        

The following code shows the Squid configuration file. For HTTPS traffic, note the ssl_bump directives instructing Squid to “peek” (retrieve the SNI) and then “splice” (become a TCP tunnel without decoding) or “terminate” the connection depending on the requested host.


visible_hostname squid
cache deny all

# Log format and rotation
logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %ssl::>sni %Sh/%<a %mt
logfile_rotate 10
debug_options rotate=10

# Handling HTTP requests
http_port 3128
http_port 3129 intercept
acl allowed_http_sites dstdomain "/etc/squid/whitelist.txt"
http_access allow allowed_http_sites

# Handling HTTPS requests
https_port 3130 cert=/etc/squid/ssl/squid.pem ssl-bump intercept
acl SSL_port port 443
http_access allow SSL_port
acl allowed_https_sites ssl::server_name "/etc/squid/whitelist.txt"
acl step1 at_step SslBump1
acl step2 at_step SslBump2
acl step3 at_step SslBump3
ssl_bump peek step1 all
ssl_bump peek step2 allowed_https_sites
ssl_bump splice step3 allowed_https_sites
ssl_bump terminate step2 all
http_access deny all       

The text file located at /etc/squid/whitelist.txt contains the list of whitelisted domains, with one domain per line. In this blog post, I’ll show you how to configure Squid to allow requests to *.amazonaws.com, which corresponds to AWS endpoints. Note that you can restrict access to a specific set of AWS services that you’ve defined (see Regions and Endpoints for a detailed list of endpoints), or you can set your own list of domains.

Note: An alternate approach is to use VPC endpoints to privately connect your VPC to supported AWS services without requiring access over the Internet (see VPC Endpoints). Some supported AWS services allow you to create a policy that controls the use of the endpoint to access AWS resources (see VPC Endpoint Policies, and VPC Endpoints for a list of supported services).

You may have noticed that Squid listens on port 3129 for HTTP traffic and 3130 for HTTPS. Because Squid cannot directly listen to 80 and 443, you have to redirect the incoming requests from instances in the private subnets to the Squid ports using iptables. You do not have to enable IP forwarding or add any FORWARD rule, as you would do with a standard NAT instance.


sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 3129
sudo iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-port 3130       

The solution stores the files squid.conf and whitelist.txt in an Amazon Simple Storage Service (S3) bucket and runs the following script every minute on the Squid instances to download and update the Squid configuration from S3. This makes it easy to maintain the Squid configuration from a central location. Note that it first validates the files with squid -k parse and then reload the configuration with squid -k reconfigure if no error was found.


        cp /etc/squid/* /etc/squid/old/
        aws s3 sync s3://<s3-bucket> /etc/squid
        squid -k parse && squid -k reconfigure || (cp /etc/squid/old/* /etc/squid/; exit 1)     

The solution then uses the CloudWatch Agent on the Squid instances to collect and store Squid logs in Amazon CloudWatch Logs. The log group /filtering-nat-instance/cache.log contains the error and debug messages that Squid generates and /filtering-nat-instance/access.log contains the access logs.

An access log record is a space-delimited string that has the following format:

<time> <response_time> <client_ip> <status_code> <size> <method> <url> <sni> <remote_host> <mime>

The following table describes the fields of an access log record.

FieldDescription
timeRequest time in seconds since epoch
response_timeResponse time in milliseconds
client_ipClient source IP address
status_codeSquid request status and HTTP response code sent to the client. For example, a HTTP request to an unallowed domain logs TCP_DENIED/403, and a HTTPS request to a whitelisted domain logs TCP_TUNNEL/200
sizeTotal size of the response sent to client
methodRequest method like GET or POST.
urlRequest URL received from the client. Logged for HTTP requests only
sniDomain name intercepted in the SNI. Logged for HTTPS requests only
remote_hostSquid hierarchy status and remote host IP address
mimeMIME content type. Logged for HTTP requests only

The following are some examples of access log records:


1563718817.184 14 10.0.0.28 TCP_DENIED/403 3822 GET http://example.com/ - HIER_NONE/- text/html
1563718821.573 7 10.0.0.28 TAG_NONE/200 0 CONNECT 172.217.7.227:443 example.com HIER_NONE/- -
1563718872.923 32 10.0.0.28 TCP_TUNNEL/200 22927 CONNECT 52.216.187.19:443 calculator.s3.amazonaws.com ORIGINAL_DST/52.216.187.19 –   

Designing a high availability solution

The Squid instances introduce a single point of failure for the private subnets. If a Squid instance fails, the instances in its associated private subnet cannot send outbound traffic anymore. The following diagram illustrates the architecture that I propose to address this situation within an Availability Zone.
 

Figure 2: The architecture to address if a Squid instance fails within an Availability Zone

Figure 2: The architecture to address if a Squid instance fails within an Availability Zone

Each Squid instance is launched in an Amazon EC2 Auto Scaling group that has a minimum size and a maximum size of one instance. A shell script is run at startup to configure the instances. That includes installing and configuring Squid (see Running Commands on Your Linux Instance at Launch).

The solution uses the CloudWatch Agent and its procstat plugin to collect the CPU usage of the Squid process every 10 seconds. For each Squid instance, the solution creates a CloudWatch alarm that watches this custom metric and goes to an ALARM state when a data point is missing. This can happen, for example, when Squid crashes or the Squid instance fails. Note that for my use case, I consider watching the Squid process a sufficient approach to determining the health status of a Squid instance, although it cannot detect eventual cases of the Squid process being alive but unable to forward traffic. As a workaround, you can use an end-to-end monitoring approach, like using witness instances in the private subnets to send test requests at regular intervals and collect the custom metric.

When an alarm goes to ALARM state, CloudWatch sends a notification to an Amazon Simple Notification Service (SNS) topic which then triggers an AWS Lambda function. The Lambda function marks the Squid instance as unhealthy in its Auto Scaling group, retrieves the list of healthy Squid instances based on the state of other CloudWatch alarms, and updates the route tables that currently route traffic to the unhealthy Squid instance to instead route traffic to the first available healthy Squid instance. While the Auto Scaling group automatically replaces the unhealthy Squid instance, private instances can send outbound traffic through the Squid instance in the other Availability Zone.

When the CloudWatch agent starts collecting the custom metric again on the replacement Squid instance, the alarm reverts to OK state. Similarly, CloudWatch sends a notification to the SNS topic, which then triggers the Lambda function. The Lambda function completes the lifecycle action (see Amazon EC2 Auto Scaling Lifecycle Hooks) to indicate that the replacement instance is ready to serve traffic, and updates the route table associated to the private subnet in the same availability zone to route traffic to the replacement instance.

Implementing and testing the solution

Now that you understand the architecture behind this solution, you can follow the instructions in this section to implement and test the solution in your AWS account.

Implementing the solution

First, you’ll use AWS CloudFormation to provision the required resources. Select the Launch Stack button below to open the CloudFormation console and create a stack from the template. Then, follow the on-screen instructions.

Select this image to open a link that starts building the CloudFormation stack

CloudFormation will create the following resources:

  • An Amazon Virtual Private Cloud (Amazon VPC) with an internet gateway attached.
  • Two public subnets and two private subnets on the Amazon VPC.
  • Three route tables. The first route table is associated to the public subnets to make them publicly accessible. The other two route tables are associated to the private subnets.
  • An S3 bucket to store the Squid configuration files, and two Lambda-based custom resources to add the files squid.conf and whitelist.txt to this bucket.
  • An IAM role to grant the Squid instances permissions to read from the S3 bucket and use the CloudWatch agent.
  • A security group to allow HTTP and HTTPS traffic from instances in the private subnets.
  • A launch configuration to specify the template of Squid instances. That includes commands to run at startup for automating the initial configuration.
  • Two Auto Scaling groups that use this launch configuration to launch the Squid instances.
  • A Lambda function to redirect the outbound traffic and recover a Squid instance when it fails.
  • Two CloudWatch alarms to watch the custom metric sent by Squid instances and trigger the Lambda function when the health status of Squid instances changes.
  • An EC2 instance in the first private subnet to test the solution, and an IAM role to grant this instance permissions to use the SSM agent. Session Manager, which I introduce in the next paragraph, uses this SSM agent (see Working with SSM Agent)

Testing the solution

After the stack creation has completed (it can take up to 10 minutes), connect onto the Testing Instance using Session Manager, a capability of AWS Systems Manager that lets you manage instances through an interactive shell without the need to open an SSH port:

  1. Open the AWS Systems Manager console.
  2. In the navigation pane, choose Session Manager.
  3. Choose Start Session.
  4. For Target instances, choose the option button to the left of Testing Instance.
  5. Choose Start Session.

Note: Session Manager makes calls to several AWS endpoints (see Working with SSM Agent). If you prefer to restrict access to a defined set of AWS services, make sure to whitelist the associated domains.

After the connection is made, you can test the solution with the following commands. Only the last three requests should return a valid response, because Squid allows traffic to *.amazonaws.com only.


curl http://www.amazon.com
curl https://www.amazon.com
curl http://calculator.s3.amazonaws.com/index.html
curl https://calculator.s3.amazonaws.com/index.html
aws ec2 describe-regions --region us-east-1         

To find the requests you just made in the access logs, here’s how to browse the Squid logs in Amazon CloudWatch Logs:

  1. Open the Amazon CloudWatch console.
  2. In the navigation pane, choose Logs.
  3. For Log Groups, choose the log group /filtering-nat-instance/access.log.
  4. Choose Search Log Group to view and search log records.

To test how the solution behaves when a Squid instance fails, you can terminate one of the Squid instances manually in the Amazon EC2 console. Then, watch the CloudWatch alarm change its state in the Amazon CloudWatch console, or watch the solution change the default route of the impacted route table in the Amazon VPC console.

You can now delete the CloudFormation stack to clean up the resources that were just created.

Discussion: Transparent or forward proxy?

The solution that I describe in this blog is fully transparent for instances in the private subnets, which means that instances don’t need to be aware of the proxy and can make requests as if they were behind a standard NAT instance. An alternate solution is to deploy a forward proxy in your Amazon VPC and configure instances in private subnets to use it (see the blog post How to set up an outbound VPC proxy with domain whitelisting and content filtering for an example). In this section, I discuss some of the differences between the two solutions.

Supportability

A major drawback with forward proxies is that the proxy must be explicitly configured on every instance within the private subnets. For example, you can configure the HTTP_PROXY and HTTPS_PROXY environment variables on Linux instances, but some applications or services, like yum, require their own proxy configuration, or don’t support proxy usage. Note also that some AWS services and features, like Amazon EMR or Amazon SageMaker notebook instances, don’t support using a forward proxy at the time of this post. However, with TLS 1.3, a forward proxy is the only option to restrict outbound traffic if the SNI is encrypted.

Scalability

Deploying a forward proxy on AWS usually consists of a load balancer distributing traffic to a set of proxy instances launched in an Auto Scaling group. Proxy instances can be launched or terminated dynamically depending on the demand (also known as “horizontal scaling”). With forward proxies, each route table can route traffic to a single instance at a time, and changing the type of the instance is the only way to increase or decrease the capacity (also known as “vertical scaling”).

The solution I present in this post does not dynamically adapt the instance type of the Squid instances based on the demand. However, you might consider a mechanism in which the traffic from a private subnet is temporarily redirected through another Availability Zone while the Squid instance is being relaunched by Auto Scaling with a smaller or larger instance type.

Mutualization

Deploying a centralized proxy solution and using it across multiple VPCs is a way of reducing cost and operational complexity.

With a forward proxy, instances in private subnets send IP packets to the proxy load balancer. Therefore, sharing a forward proxy across multiple VPCs only requires connectivity between the “instance VPCs” and a proxy VPC that has VPC Peering or equivalent capabilities.

With a transparent proxy, instances in private subnets sends IP packets to the remote host. VPC Peering does not support transitive routing (see Unsupported VPC Peering Configurations) and cannot be used to share a transparent proxy across multiple VPCs. However, you can now use an AWS Transit Gateway that acts as a network transit hub to share a transparent proxy across multiple VPCs. I give an example in the next section.

Sharing the solution across multiple VPCs using AWS Transit Gateway

In this section, I give an example of how to share a transparent proxy across multiple VPCs using AWS Transit Gateway. The architecture is illustrated in the following diagram. For the sake of simplicity, the diagram does not include Availability Zones.
 

Figure 3: The architecture for a transparent proxy across multiple VPCs using AWS Transit Gateway

Figure 3: The architecture for a transparent proxy across multiple VPCs using AWS Transit Gateway

Here’s how instances in the private subnet of “VPC App” can make requests via the shared transparent proxy in “VPC Shared:”

  1. When instances in VPC App make HTTP/S requests, the network packets they send have the public IP address of the remote host as the destination address. These packets are forwarded to the transit gateway, based on the route table associated to the private subnet.
  2. The transit gateway receives the packets and forwards them to VPC Shared, based on the default route of the transit gateway route table.
  3. Note that the transit gateway attachment resides in the transit gateway subnet. When the packets arrive in VPC Shared, they are forwarded to the Squid instance because the next destination has been determined based on the route table associated to the transit gateway subnet.
  4. The Squid instance makes requests on behalf of the source instance (“Instances” in the schema). Then, it sends the response to the source instance. The packets that it emits have the IP address of the source instance as the destination address and are forwarded to the transit gateway according to the route table associated to the public subnet.
  5. The transit gateway receives and forwards the response packets to VPC App.
  6. Finally, the response reaches the source instance.

In a high availability deployment, you could have one transit gateway subnet per Availability Zone that sends traffic to the Squid instance that resides in the same Availability Zone, or to the Squid instance in another Availability Zone if the instance in the same Availability Zone fails.

You could also use AWS Transit Gateway to implement a transparent proxy solution that scales horizontally. This allows you to add or remove proxy instances based on the demand, instead of changing the instance type. With this approach, you must deploy a fleet of proxy instances – launched by an Auto Scaling group, for example – and mount a VPN connection between each instance and the transit gateway. The proxy instances need to support ECMP (“Equal Cost Multipath routing”; see Transit Gateways) to equally spread the outbound traffic between instances. I don’t describe this alternative architecture further in this blog post.

Conclusion

In this post, I’ve shown how you can use Squid to implement a high availability solution that filters outgoing traffic to the Internet and helps meet your security and compliance needs, while being fully transparent for the back-end instances in your VPC. I’ve also discussed the key differences between transparent proxies and forward proxies. Finally, I gave an example of how to share a transparent proxy solution across multiple VPCs using AWS Transit Gateway.

If you have any questions or suggestions, please leave a comment below or on the Amazon VPC forum.

If you have feedback about this blog post, submit comments in the Comments section below.

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Nicolas Malaval

Nicolas is a Solution Architect for Amazon Web Services. He lives in Paris and helps our healthcare customers in France adopt cloud technology and innovate with AWS. Before that, he spent three years as a Consultant for AWS Professional Services, working with enterprise customers.

Foxtel Obtains First ‘Dynamic’ Injunction Against Torrent, Streaming & Proxy Sites

Post Syndicated from Andy original https://torrentfreak.com/foxtel-obtains-first-dynamic-injunction-against-torrent-streaming-proxy-sites-190827/

Section 115a of Australia’s Copyright Act, which provides a mechanism for rightsholders to have ‘pirate’ sites blocked by ISPs, was long campaigned for as an essential tool to fight online infringement.

Since it came into force it has been used on a number of occasions, with the Federal Court handing down orders to restrict access to hundreds of sites said to provide access to entertainment content without permission from the rightsholders.

Back in June, media giant Foxtel filed a new statement of claim, the details of which were obtained by TorrentFreak from a third-party source. It revealed that the company was targeting 35 torrent, streaming and related proxy site domains for blocking by dozens of ISPs (full site list below).

This was the first time that a rightsholder had targeted proxy sites in Australia. A change in the law during 2018 allowed sites that have a “primary effect” of facilitating access to infringing content to be blocked, along with more direct sources such as regular pirate sites.

Following a case management hearing that took place in July, a hearing this morning resulted in Justice Nicholas handing down an injunction ordering 52 ISPs including TPG, Telstra, Optus, Vocus, Vodafone, plus their subsidiaries, to take “reasonable steps” to block the “online locations”.

A unique aspect of this application was that Foxtel had asked permission to add new domains and URLs to its orders, ones that in future might facilitate access to already-blocked sites, without having to return to court to detail them specifically.

Under legislative amendments put in place last year (Copyright Amendment (Online Infringement) Bill 2018)), these kinds of “dynamic orders” are permissible, but only when the Internet service providers listed in the application don’t file an objection.

According to ComputerWorld, the hearing this morning had Foxtel counsel stating that it wasn’t seeking to block fresh additional “online locations”, but only proxy and mirror-type sites those that spring up to facilitate access to already blocked sites.

However, Foxtel acknowledged that getting all of the respondent ISPs to agree to such supplementary blocking raised issues since TPG tends not to respond to any of the blocking injunctions it’s named in. That meant that formal agreement between all ISPs might be difficult to obtain.

With Justice Nicholas’ permission, Foxtel said it would amend its proposed orders to include a provision allowing an ISP to positively deny that a proxy, mirror, or similar facilitating site, provides access to a blocked site. This would likely overcome that particular stumbling block, the Judge agreed.

The associated court documents can be found here and here (pdf)

The list of domains to be blocked by ISPs in 15 days are as follows:

Sharemovies.net, seriesonline8.co, seriesonline8.com, movie4u.live, movie4u.cc, movie4u.co, seehd.uno, seehd.biz, streamdreams.org, streamdreams.me, streamdreams.co, streamdreams.online, streamdreams.video, stream-dreams.com, moviesonline.mx, wsmmirror.info, watchsomuch.info, watchsomuch.com, seventorrentsmirror.info, seventorrentsproxy.com, 7tmirror.info, torrentken.site, skytorrents.lol, unblocked.lol, unblocked.is, unblocked.ms, unblocked.win, unblocked.gdn, unblocked.vet, unblocked,sh, unblocked.mx, unblockall.org, unblocker.cc, unblock.win, myunblock.com

Source: TF, for the latest info on copyright, file-sharing, torrent sites and more. We also have VPN reviews, discounts, offers and coupons.

Security updates for Thursday

Post Syndicated from ris original https://lwn.net/Articles/756164/rss

Security updates have been issued by CentOS (389-ds-base, corosync, firefox, java-1.7.0-openjdk, java-1.8.0-openjdk, kernel, librelp, libvirt, libvncserver, libvorbis, PackageKit, patch, pcs, and qemu-kvm), Fedora (asterisk, ca-certificates, gifsicle, ncurses, nodejs-base64-url, nodejs-mixin-deep, and wireshark), Mageia (thunderbird), Red Hat (procps), SUSE (curl, kvm, and libvirt), and Ubuntu (apport, haproxy, and tomcat7, tomcat8).

Putin Asked to Investigate Damage Caused By Telegram Web-Blocking

Post Syndicated from Andy original https://torrentfreak.com/putin-asked-to-investigate-damage-caused-by-telegram-web-blocking-180526/

After a Moscow court gave the go-ahead for Telegram to be banned in Russia last month, the Internet became a battleground.

On the instructions of telecoms watchdog Roscomnadzor, ISPs across Russia tried to block Telegram by blackholing millions of IP addresses. The effect was both dramatic and pathetic. While Telegram remained stubbornly online, countless completely innocent services suffered outages as Roscomnadzor charged ahead with its mission.

Over the past several weeks, Roscomnadzor has gone some way to clean up the mess, partly by removing innocent Google and Amazon IP addresses from Russia’s blacklist. However, the collateral damage was so widespread it’s called into question the watchdog’s entire approach to web-blockades and whether they should be carried out at any cost.

This week, thanks to an annual report presented to President Vladimir Putin by business ombudsman Boris Titov, the matter looks set to be escalated. ‘The Book of Complaints and Suggestions of Russian Business’ contains comments from Internet ombudsman Dmitry Marinichev, who says that the Prosecutor General’s Office should launch an investigation into Roscomnadzor’s actions.

Marinichev said that when attempting to take down Telegram using aggressive technical means, Roscomnadzor relied upon “its own interpretation of court decisions” to provide guidance, TASS reports.

“When carrying out blockades of information resources, Roskomnadzor did not assess the related damage caused to them,” he said.

More than 15 million IP addresses were blocked, many of them with functions completely unrelated to the operations of Telegram. Marinichev said that the consequences were very real for those who suffered collateral damage.

“[The blocking led] to a temporary inaccessibility of Internet resources of a number of Russian enterprises in the Internet sector, including several banks and government information resources,” he reported.

In advice to the President, Marinichev suggests that the Prosecutor General’s Office should look into “the legality and validity of Roskomnadzor’s actions” which led to the “violation of availability of information resources of commercial companies” and “threatened the integrity, sustainability, and functioning of the unified telecommunications network of the Russian Federation and its critical information infrastructure.”

Early May, it was reported that in addition to various web services, around 50 VPN, proxy and anonymization platforms had been blocked for providing access to Telegram. In a May 22 report, that number had swelled to more than 80 although 10 were later unblocked after they stopped providing access to the messaging platform.

This week, Roscomnadzor has continued with efforts to block access to torrent and streaming platforms. In a new wave of action, the telecoms watchdog ordered ISPs to block at least 47 mirrors and proxies providing access to previously blocked sites.

Source: TF, for the latest info on copyright, file-sharing, torrent sites and more. We also have VPN reviews, discounts, offers and coupons.

Use Slack ChatOps to Deploy Your Code – How to Integrate Your Pipeline in AWS CodePipeline with Your Slack Channel

Post Syndicated from Rumi Olsen original https://aws.amazon.com/blogs/devops/use-slack-chatops-to-deploy-your-code-how-to-integrate-your-pipeline-in-aws-codepipeline-with-your-slack-channel/

Slack is widely used by DevOps and development teams to communicate status. Typically, when a build has been tested and is ready to be promoted to a staging environment, a QA engineer or DevOps engineer kicks off the deployment. Using Slack in a ChatOps collaboration model, the promotion can be done in a single click from a Slack channel. And because the promotion happens through a Slack channel, the whole development team knows what’s happening without checking email.

In this blog post, I will show you how to integrate AWS services with a Slack application. I use an interactive message button and incoming webhook to promote a stage with a single click.

To follow along with the steps in this post, you’ll need a pipeline in AWS CodePipeline. If you don’t have a pipeline, the fastest way to create one for this use case is to use AWS CodeStar. Go to the AWS CodeStar console and select the Static Website template (shown in the screenshot). AWS CodeStar will create a pipeline with an AWS CodeCommit repository and an AWS CodeDeploy deployment for you. After the pipeline is created, you will need to add a manual approval stage.

You’ll also need to build a Slack app with webhooks and interactive components, write two Lambda functions, and create an API Gateway API and a SNS topic.

As you’ll see in the following diagram, when I make a change and merge a new feature into the master branch in AWS CodeCommit, the check-in kicks off my CI/CD pipeline in AWS CodePipeline. When CodePipeline reaches the approval stage, it sends a notification to Amazon SNS, which triggers an AWS Lambda function (ApprovalRequester).

The Slack channel receives a prompt that looks like the following screenshot. When I click Yes to approve the build promotion, the approval result is sent to CodePipeline through API Gateway and Lambda (ApprovalHandler). The pipeline continues on to deploy the build to the next environment.

Create a Slack app

For App Name, type a name for your app. For Development Slack Workspace, choose the name of your workspace. You’ll see in the following screenshot that my workspace is AWS ChatOps.

After the Slack application has been created, you will see the Basic Information page, where you can create incoming webhooks and enable interactive components.

To add incoming webhooks:

  1. Under Add features and functionality, choose Incoming Webhooks. Turn the feature on by selecting Off, as shown in the following screenshot.
  2. Now that the feature is turned on, choose Add New Webhook to Workspace. In the process of creating the webhook, Slack lets you choose the channel where messages will be posted.
  3. After the webhook has been created, you’ll see its URL. You will use this URL when you create the Lambda function.

If you followed the steps in the post, the pipeline should look like the following.

Write the Lambda function for approval requests

This Lambda function is invoked by the SNS notification. It sends a request that consists of an interactive message button to the incoming webhook you created earlier.  The following sample code sends the request to the incoming webhook. WEBHOOK_URL and SLACK_CHANNEL are the environment variables that hold values of the webhook URL that you created and the Slack channel where you want the interactive message button to appear.

# This function is invoked via SNS when the CodePipeline manual approval action starts.
# It will take the details from this approval notification and sent an interactive message to Slack that allows users to approve or cancel the deployment.

import os
import json
import logging
import urllib.parse

from base64 import b64decode
from urllib.request import Request, urlopen
from urllib.error import URLError, HTTPError

# This is passed as a plain-text environment variable for ease of demonstration.
# Consider encrypting the value with KMS or use an encrypted parameter in Parameter Store for production deployments.
SLACK_WEBHOOK_URL = os.environ['SLACK_WEBHOOK_URL']
SLACK_CHANNEL = os.environ['SLACK_CHANNEL']

logger = logging.getLogger()
logger.setLevel(logging.INFO)

def lambda_handler(event, context):
    print("Received event: " + json.dumps(event, indent=2))
    message = event["Records"][0]["Sns"]["Message"]
    
    data = json.loads(message) 
    token = data["approval"]["token"]
    codepipeline_name = data["approval"]["pipelineName"]
    
    slack_message = {
        "channel": SLACK_CHANNEL,
        "text": "Would you like to promote the build to production?",
        "attachments": [
            {
                "text": "Yes to deploy your build to production",
                "fallback": "You are unable to promote a build",
                "callback_id": "wopr_game",
                "color": "#3AA3E3",
                "attachment_type": "default",
                "actions": [
                    {
                        "name": "deployment",
                        "text": "Yes",
                        "style": "danger",
                        "type": "button",
                        "value": json.dumps({"approve": True, "codePipelineToken": token, "codePipelineName": codepipeline_name}),
                        "confirm": {
                            "title": "Are you sure?",
                            "text": "This will deploy the build to production",
                            "ok_text": "Yes",
                            "dismiss_text": "No"
                        }
                    },
                    {
                        "name": "deployment",
                        "text": "No",
                        "type": "button",
                        "value": json.dumps({"approve": False, "codePipelineToken": token, "codePipelineName": codepipeline_name})
                    }  
                ]
            }
        ]
    }

    req = Request(SLACK_WEBHOOK_URL, json.dumps(slack_message).encode('utf-8'))

    response = urlopen(req)
    response.read()
    
    return None

 

Create a SNS topic

Create a topic and then create a subscription that invokes the ApprovalRequester Lambda function. You can configure the manual approval action in the pipeline to send a message to this SNS topic when an approval action is required. When the pipeline reaches the approval stage, it sends a notification to this SNS topic. SNS publishes a notification to all of the subscribed endpoints. In this case, the Lambda function is the endpoint. Therefore, it invokes and executes the Lambda function. For information about how to create a SNS topic, see Create a Topic in the Amazon SNS Developer Guide.

Write the Lambda function for handling the interactive message button

This Lambda function is invoked by API Gateway. It receives the result of the interactive message button whether or not the build promotion was approved. If approved, an API call is made to CodePipeline to promote the build to the next environment. If not approved, the pipeline stops and does not move to the next stage.

The Lambda function code might look like the following. SLACK_VERIFICATION_TOKEN is the environment variable that contains your Slack verification token. You can find your verification token under Basic Information on Slack manage app page. When you scroll down, you will see App Credential. Verification token is found under the section.

# This function is triggered via API Gateway when a user acts on the Slack interactive message sent by approval_requester.py.

from urllib.parse import parse_qs
import json
import os
import boto3

SLACK_VERIFICATION_TOKEN = os.environ['SLACK_VERIFICATION_TOKEN']

#Triggered by API Gateway
#It kicks off a particular CodePipeline project
def lambda_handler(event, context):
	#print("Received event: " + json.dumps(event, indent=2))
	body = parse_qs(event['body'])
	payload = json.loads(body['payload'][0])

	# Validate Slack token
	if SLACK_VERIFICATION_TOKEN == payload['token']:
		send_slack_message(json.loads(payload['actions'][0]['value']))
		
		# This will replace the interactive message with a simple text response.
		# You can implement a more complex message update if you would like.
		return  {
			"isBase64Encoded": "false",
			"statusCode": 200,
			"body": "{\"text\": \"The approval has been processed\"}"
		}
	else:
		return  {
			"isBase64Encoded": "false",
			"statusCode": 403,
			"body": "{\"error\": \"This request does not include a vailid verification token.\"}"
		}


def send_slack_message(action_details):
	codepipeline_status = "Approved" if action_details["approve"] else "Rejected"
	codepipeline_name = action_details["codePipelineName"]
	token = action_details["codePipelineToken"] 

	client = boto3.client('codepipeline')
	response_approval = client.put_approval_result(
							pipelineName=codepipeline_name,
							stageName='Approval',
							actionName='ApprovalOrDeny',
							result={'summary':'','status':codepipeline_status},
							token=token)
	print(response_approval)

 

Create the API Gateway API

  1. In the Amazon API Gateway console, create a resource called InteractiveMessageHandler.
  2. Create a POST method.
    • For Integration type, choose Lambda Function.
    • Select Use Lambda Proxy integration.
    • From Lambda Region, choose a region.
    • In Lambda Function, type a name for your function.
  3.  Deploy to a stage.

For more information, see Getting Started with Amazon API Gateway in the Amazon API Developer Guide.

Now go back to your Slack application and enable interactive components.

To enable interactive components for the interactive message (Yes) button:

  1. Under Features, choose Interactive Components.
  2. Choose Enable Interactive Components.
  3. Type a request URL in the text box. Use the invoke URL in Amazon API Gateway that will be called when the approval button is clicked.

Now that all the pieces have been created, run the solution by checking in a code change to your CodeCommit repo. That will release the change through CodePipeline. When the CodePipeline comes to the approval stage, it will prompt to your Slack channel to see if you want to promote the build to your staging or production environment. Choose Yes and then see if your change was deployed to the environment.

Conclusion

That is it! You have now created a Slack ChatOps solution using AWS CodeCommit, AWS CodePipeline, AWS Lambda, Amazon API Gateway, and Amazon Simple Notification Service.

Now that you know how to do this Slack and CodePipeline integration, you can use the same method to interact with other AWS services using API Gateway and Lambda. You can also use Slack’s slash command to initiate an action from a Slack channel, rather than responding in the way demonstrated in this post.

Security updates for Wednesday

Post Syndicated from ris original https://lwn.net/Articles/754653/rss

Security updates have been issued by CentOS (dhcp), Debian (xen), Fedora (dhcp, flac, kubernetes, leptonica, libgxps, LibRaw, matrix-synapse, mingw-LibRaw, mysql-mmm, patch, seamonkey, webkitgtk4, and xen), Mageia (389-ds-base, exempi, golang, graphite2, libpam4j, libraw, libsndfile, libtiff, perl, quassel, spring-ldap, util-linux, and wget), Oracle (dhcp and kernel), Red Hat (389-ds-base, chromium-browser, dhcp, docker-latest, firefox, kernel-alt, libvirt, qemu-kvm, redhat-vertualization-host, rh-haproxy18-haproxy, and rhvm-appliance), Scientific Linux (389-ds-base, dhcp, firefox, libvirt, and qemu-kvm), and Ubuntu (poppler).

[$] Who controls glibc?

Post Syndicated from corbet original https://lwn.net/Articles/753646/rss

The removal of an old joke from the GNU C Library manual might not seem
like the sort of topic that would inspire a heated debate. At times,
though, a small action can serve as an inadvertent proxy for a more
significant question, one which is relevant to both the developers and the
users of the project. In this case, that question would be:
how is the project governed and who
makes decisions about which patches are applied?

Backblaze Announces B2 Compute Partnerships

Post Syndicated from Gleb Budman original https://www.backblaze.com/blog/introducing-cloud-compute-services/

Backblaze Announces B2 Compute Partnerships

In 2015, we announced Backblaze B2 Cloud Storage — the most affordable, high performance storage cloud on the planet. The decision to release B2 as a service was in direct response to customers asking us if they could use the same cloud storage infrastructure we use for our Computer Backup service. With B2, we entered a market in direct competition with Amazon S3, Google Cloud Services, and Microsoft Azure Storage. Today, we have over 500 petabytes of data from customers in over 150 countries. At $0.005 / GB / month for storage (1/4th of S3) and $0.01 / GB for downloads (1/5th of S3), it turns out there’s a healthy market for cloud storage that’s easy and affordable.

As B2 has grown, customers wanted to use our cloud storage for a variety of use cases that required not only storage but compute. We’re happy to say that through partnerships with Packet & ServerCentral, today we’re announcing that compute is now available for B2 customers.

Cloud Compute and Storage

Backblaze has directly connected B2 with the compute servers of Packet and ServerCentral, thereby allowing near-instant (< 10 ms) data transfers between services. Also, transferring data between B2 and both our compute partners is free.

  • Storing data in B2 and want to run an AI analysis on it? — There are no fees to move the data to our compute partners.
  • Generating data in an application? — Run the application with one of our partners and store it in B2.
  • Transfers are free and you’ll save more than 50% off of the equivalent set of services from AWS.

These partnerships enable B2 customers to use compute, give our compute partners’ customers access to cloud storage, and introduce new customers to industry-leading storage and compute — all with high-performance, low-latency, and low-cost.

Is This a Big Deal? We Think So

Compute is one of the most requested services from our customers Why? Because it unlocks a number of use cases for them. Let’s look at three popular examples:

Transcoding Media Files

B2 has earned wide adoption in the Media & Entertainment (“M&E”) industry. Our affordable storage and download pricing make B2 great for a wide variety of M&E use cases. But many M&E workflows require compute. Content syndicators, like American Public Television, need the ability to transcode files to meet localization and distribution management requirements.

There are a multitude of reasons that transcode is needed — thumbnail and proxy generation enable M&E professionals to work efficiently. Without compute, the act of transcoding files remains cumbersome. Either the files need to be brought down from the cloud, transcoded, and then pushed back up or they must be kept locally until the project is complete. Both scenarios are inefficient.

Starting today, any content producer can spin up compute with one of our partners, pay by the hour for their transcode processing, and return the new media files to B2 for storage and distribution. The company saves money, moves faster, and ensures their files are safe and secure.

Disaster Recovery

Backblaze’s heritage is based on providing outstanding backup services. When you have incredibly affordable cloud storage, it ends up being a great destination for your backup data.

Most enterprises have virtual machines (“VMs”) running in their infrastructure and those VMs need to be backed up. In a disaster scenario, a business wants to know they can get back up and running quickly.

With all data stored in B2, a business can get up and running quickly. Simply restore your backed up VM to one of our compute providers, and your business will be able to get back online.

Since B2 does not place restrictions, delays, or penalties on getting data out, customers can get back up and running quickly and affordably.

Saving $74 Million (aka “The Dropbox Effect”)

Ten years ago, Backblaze decided that S3 was too costly a platform to build its cloud storage business. Instead, we created the Backblaze Storage Pod and our own cloud storage infrastructure. That decision enabled us to offer our customers storage at a previously unavailable price point and maintain those prices for over a decade. It also laid the foundation for Netflix Open Connect and Facebook Open Compute.

Dropbox recently migrated the majority of their cloud services off of AWS and onto Dropbox’s own infrastructure. By leaving AWS, Dropbox was able to build out their own data centers and still save over $74 Million. They achieved those savings by avoiding the fees AWS charges for storing and downloading data, which, incidentally, are five times higher than Backblaze B2.

For Dropbox, being able to realize savings was possible because they have access to enough capital and expertise that they can build out their own infrastructure. For companies that have such resources and scale, that’s a great answer.

“Before this offering, the economics of the cloud would have made our business simply unviable.” — Gabriel Menegatti, SlicingDice

The questions Backblaze and our compute partners pondered was “how can we democratize the Dropbox effect for our storage and compute customers? How can we help customers do more and pay less?” The answer we came up with was to connect Backblaze’s B2 storage with strategic compute partners and remove any transfer fees between them. You may not save $74 million as Dropbox did, but you can choose the optimal providers for your use case and realize significant savings in the process.

This Sounds Good — Tell Me More About Your Partners

We’re very fortunate to be launching our compute program with two fantastic partners in Packet and ServerCentral. These partners allow us to offer a range of computing services.

Packet

We recommend Packet for customers that need on-demand, high performance, bare metal servers available by the hour. They also have robust offerings for private / customized deployments. Their offerings end up costing 50-75% of the equivalent offerings from EC2.

To get started with Packet and B2, visit our partner page on Packet.net.

ServerCentral

ServerCentral is the right partner for customers that have business and IT challenges that require more than “just” hardware. They specialize in fully managed, custom cloud solutions that solve complex business and IT challenges. ServerCentral also has expertise in managed network solutions to address global connectivity and content delivery.

To get started with ServerCentral and B2, visit our partner page on ServerCentral.com.

What’s Next?

We’re excited to find out. The combination of B2 and compute unlocks use cases that were previously impossible or at least unaffordable.

“The combination of performance and price offered by this partnership enables me to create an entirely new business line. Before this offering, the economics of the cloud would have made our business simply unviable,” noted Gabriel Menegatti, co-founder at SlicingDice, a serverless data warehousing service. “Knowing that transfers between compute and B2 are free means I don’t have to worry about my business being successful. And, with download pricing from B2 at just $0.01 GB, I know I’m avoiding a 400% tax from AWS on data I retrieve.”

What can you do with B2 & compute? Please share your ideas with us in the comments. And, for those attending NAB 2018 in Las Vegas next week, please come by and say hello!

The post Backblaze Announces B2 Compute Partnerships appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Secure Images

Post Syndicated from marcelatoath original https://yahooeng.tumblr.com/post/172068649246

oath-postmaster:

By Marcel Becker

The mail team at OATH is busy  integrating  Yahoo and AOL technology to deliver an even better experience across all our consumer mail products. While privacy and security are top priority for us, we also want to improve the experience and remove unnecessary clutter across all of our products.

Starting this week we will be serving images in mails via our own secure proxy servers. This will not only increase speed and security in our own mail products and reduce the risk of phishing and other scams,  but it will also mean that our users don’t have to fiddle around with those “enable images” settings. Messages and inline images will now just show up as originally intended.

We are aware that commercial mail senders are relying on images (so-called pixels) to track delivery and open rates. Our proxy solution will continue to support most of these cases and ensure that true mail opens are recorded.

For senders serving dynamic content based on the recipient’s location (leveraging standard IP-based browser and app capabilities) we recommend falling back on other tools and technologies which do not rely on IP-based targeting.

All of our consumer mail applications (Yahoo and AOL) will benefit from this change. This includes our desktop products as well as our mobile applications across iOS and Android.

If you have any feedback or want to discuss those changes with us personally, just send us a note to [email protected].

Secure Images

Post Syndicated from marcelatoath original https://yahooeng.tumblr.com/post/172037447286

By Marcel Becker

The mail team at OATH is busy  integrating  Yahoo and AOL technology to deliver an even better experience across all our consumer mail products. While privacy and security are top priority for us, we also want to improve the experience and remove unnecessary clutter across all of our products.

Starting this week we will be serving images in mails via our own secure proxy servers. This will not only increase speed and security in our own mail products and reduce the risk of phishing and other scams,  but it will also mean that our users don’t have to fiddle around with those “enable images” settings. Messages and inline images will now just show up as originally intended.

We are aware that commercial mail senders are relying on images (so-called pixels) to track delivery and open rates. Our proxy solution will continue to support most of these cases and ensure that true mail opens are recorded.

For senders serving dynamic content based on the recipient’s location (leveraging standard IP-based browser and app capabilities) we recommend falling back on other tools and technologies which do not rely on IP-based targeting.

All of our consumer mail applications (Yahoo and AOL) will benefit from this change. This includes our desktop products as well as our mobile applications across iOS and Android.

If you have any feedback or want to discuss those changes with us personally, just send us a note to [email protected].

Serverless Dynamic Web Pages in AWS: Provisioned with CloudFormation

Post Syndicated from AWS Admin original https://aws.amazon.com/blogs/architecture/serverless-dynamic-web-pages-in-aws-provisioned-with-cloudformation/

***This blog is authored by Mike Okner of Monsanto, an AWS customer. It originally appeared on the Monsanto company blog. Minor edits were made to the original post.***

Recently, I was looking to create a status page app to monitor a few important internal services. I wanted this app to be as lightweight, reliable, and hassle-free as possible, so using a “serverless” architecture that doesn’t require any patching or other maintenance was quite appealing.

I also don’t deploy anything in a production AWS environment outside of some sort of template (usually CloudFormation) as a rule. I don’t want to have to come back to something I created ad hoc in the console after 6 months and try to recall exactly how I architected all of the resources. I’ll inevitably forget something and create more problems before solving the original one. So building the status page in a template was a requirement.

The Design
I settled on a design using two Lambda functions, both written in Python 3.6.

The first Lambda function makes requests out to a list of important services and writes their current status to a DynamoDB table. This function is executed once per minute via CloudWatch Event Rule.

The second Lambda function reads each service’s status & uptime information from DynamoDB and renders a Jinja template. This function is behind an API Gateway that has been configured to return text/html instead of its default application/json Content-Type.

The CloudFormation Template
AWS provides a Serverless Application Model template transformer to streamline the templating of Lambda + API Gateway designs, but it assumes (like everything else about the API Gateway) that you’re actually serving an API that returns JSON content. So, unfortunately, it won’t work for this use-case because we want to return HTML content. Instead, we’ll have to enumerate every resource like usual.

The Skeleton
We’ll be using YAML for the template in this example. I find it easier to read than JSON, but you can easily convert between the two with a converter if you disagree.

---
AWSTemplateFormatVersion: '2010-09-09'
Description: Serverless status page app
Resources:
  # [...Resources]

The Status-Checker Lambda Resource
This one is triggered on a schedule by CloudWatch, and looks like:

# Status Checker Lambda
CheckerLambda:
  Type: AWS::Lambda::Function
  Properties:
    Code: ./lambda.zip
    Environment:
      Variables:
        TABLE_NAME: !Ref DynamoTable
    Handler: checker.handler
    Role:
      Fn::GetAtt:
      - CheckerLambdaRole
      - Arn
    Runtime: python3.6
    Timeout: 45
CheckerLambdaRole:
  Type: AWS::IAM::Role
  Properties:
    ManagedPolicyArns:
    - arn:aws:iam::aws:policy/AmazonDynamoDBFullAccess
    - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
    AssumeRolePolicyDocument:
      Version: '2012-10-17'
      Statement:
      - Action:
        - sts:AssumeRole
        Effect: Allow
        Principal:
          Service:
          - lambda.amazonaws.com
CheckerLambdaTimer:
  Type: AWS::Events::Rule
  Properties:
    ScheduleExpression: rate(1 minute)
    Targets:
    - Id: CheckerLambdaTimerLambdaTarget
      Arn:
        Fn::GetAtt:
        - CheckerLambda
        - Arn
CheckerLambdaTimerPermission:
  Type: AWS::Lambda::Permission
  Properties:
    Action: lambda:invokeFunction
    FunctionName: !Ref CheckerLambda
    SourceArn:
      Fn::GetAtt:
      - CheckerLambdaTimer
      - Arn
    Principal: events.amazonaws.com

Let’s break that down a bit.

The CheckerLambda is the actual Lambda function. The Code section is a local path to a ZIP file containing the code and its dependencies. I’m using CloudFormation’s packaging feature to automatically push the deployable to S3.

The CheckerLambdaRole is the IAM role the Lambda will assume which grants it access to DynamoDB in addition to the usual Lambda logging permissions.

The CheckerLambdaTimer is the CloudWatch Events Rule that triggers the checker to run once per minute.

The CheckerLambdaTimerPermission grants CloudWatch the ability to invoke the checker Lambda function on its interval.

The Web Page Gateway
The API Gateway handles incoming requests for the web page, invokes the Lambda, and then returns the Lambda’s results as HTML content. Its template looks like:

# API Gateway for Web Page Lambda
PageGateway:
  Type: AWS::ApiGateway::RestApi
  Properties:
    Name: Service Checker Gateway
PageResource:
  Type: AWS::ApiGateway::Resource
  Properties:
    RestApiId: !Ref PageGateway
    ParentId:
      Fn::GetAtt:
      - PageGateway
      - RootResourceId
    PathPart: page
PageGatewayMethod:
  Type: AWS::ApiGateway::Method
  Properties:
    AuthorizationType: NONE
    HttpMethod: GET
    Integration:
      Type: AWS
      IntegrationHttpMethod: POST
      Uri:
        Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${WebRenderLambda.Arn}/invocations
      RequestTemplates:
        application/json: |
          {
              "method": "$context.httpMethod",
              "body" : $input.json('$'),
              "headers": {
                  #foreach($param in $input.params().header.keySet())
                  "$param": "$util.escapeJavaScript($input.params().header.get($param))"
                  #if($foreach.hasNext),#end
                  #end
              }
          }
      IntegrationResponses:
      - StatusCode: 200
        ResponseParameters:
          method.response.header.Content-Type: "'text/html'"
        ResponseTemplates:
          text/html: "$input.path('$')"
    ResourceId: !Ref PageResource
    RestApiId: !Ref PageGateway
    MethodResponses:
    - StatusCode: 200
      ResponseParameters:
        method.response.header.Content-Type: true
PageGatewayProdStage:
  Type: AWS::ApiGateway::Stage
  Properties:
    DeploymentId: !Ref PageGatewayDeployment
    RestApiId: !Ref PageGateway
    StageName: Prod
PageGatewayDeployment:
  Type: AWS::ApiGateway::Deployment
  DependsOn: PageGatewayMethod
  Properties:
    RestApiId: !Ref PageGateway
    Description: PageGateway deployment
    StageName: Stage

There’s a lot going on here, but the real meat is in the PageGatewayMethod section. There are a couple properties that deviate from the default which is why we couldn’t use the SAM transformer.

First, we’re passing request headers through to the Lambda in theRequestTemplates section. I’m doing this so I can validate incoming auth headers. The API Gateway can do some types of auth, but I found it easier to check auth myself in the Lambda function since the Gateway is designed to handle API calls and not browser requests.

Next, note that in the IntegrationResponses section we’re defining the Content-Type header to be ‘text/html’ (with single-quotes) and defining the ResponseTemplate to be $input.path(‘$’). This is what makes the request render as a HTML page in your browser instead of just raw text.

Due to the StageName and PathPart values in the other sections, your actual page will be accessible at https://someId.execute-api.region.amazonaws.com/Prod/page. I have the page behind an existing reverse-proxy and give it a saner URL for end-users. The reverse proxy also attaches the auth header I mentioned above. If that header isn’t present, the Lambda will render an error page instead so the proxy can’t be bypassed.

The Web Page Rendering Lambda
This Lambda is invoked by calls to the API Gateway and looks like:

# Web Page Lambda
WebRenderLambda:
  Type: AWS::Lambda::Function
  Properties:
    Code: ./lambda.zip
    Environment:
      Variables:
        TABLE_NAME: !Ref DynamoTable
    Handler: web.handler
    Role:
      Fn::GetAtt:
      - WebRenderLambdaRole
      - Arn
    Runtime: python3.6
    Timeout: 30
WebRenderLambdaRole:
  Type: AWS::IAM::Role
  Properties:
    ManagedPolicyArns:
    - arn:aws:iam::aws:policy/AmazonDynamoDBReadOnlyAccess
    - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
    AssumeRolePolicyDocument:
      Version: '2012-10-17'
      Statement:
      - Action:
        - sts:AssumeRole
        Effect: Allow
        Principal:
          Service:
          - lambda.amazonaws.com
WebRenderLambdaGatewayPermission:
  Type: AWS::Lambda::Permission
  Properties:
    FunctionName: !Ref WebRenderLambda
    Action: lambda:invokeFunction
    Principal: apigateway.amazonaws.com
    SourceArn:
      Fn::Sub:
      - arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${__ApiId__}/*/*/*
      - __ApiId__: !Ref PageGateway

The WebRenderLambda and WebRenderLambdaRole should look familiar.

The WebRenderLambdaGatewayPermission is similar to the Status Checker’s CloudWatch permission, only this time it allows the API Gateway to invoke this Lambda.

The DynamoDB Table
This one is straightforward.

# DynamoDB table
DynamoTable:
  Type: AWS::DynamoDB::Table
  Properties:
    AttributeDefinitions:
    - AttributeName: name
      AttributeType: S
    ProvisionedThroughput:
      WriteCapacityUnits: 1
      ReadCapacityUnits: 1
    TableName: status-page-checker-results
    KeySchema:
    - KeyType: HASH
      AttributeName: name

The Deployment
We’ve made it this far defining every resource in a template that we can check in to version control, so we might as well script the deployment as well rather than manually manage the CloudFormation Stack via the AWS web console.

Since I’m using the packaging feature, I first run:

$ aws cloudformation package \
    --template-file template.yaml \
    --s3-bucket <some-bucket-name> \
    --output-template-file template-packaged.yaml
Uploading to 34cd6e82c5e8205f9b35e71afd9e1548 1922559 / 1922559.0 (100.00%) Successfully packaged artifacts and wrote output template to file template-packaged.yaml.

Then to deploy the template (whether new or modified), I run:

$ aws cloudformation deploy \
    --region '<aws-region>' \
    --template-file template-packaged.yaml \
    --stack-name '<some-name>' \
    --capabilities CAPABILITY_IAM
Waiting for changeset to be created.. Waiting for stack create/update to complete Successfully created/updated stack - <some-name>

And that’s it! You’ve just created a dynamic web page that will never require you to SSH anywhere, patch a server, recover from a disaster after Amazon terminates your unhealthy EC2, or any other number of pitfalls that are now the problem of some ops person at AWS. And you can reproduce deployments and make changes with confidence because everything is defined in the template and can be tracked in version control.

timeShift(GrafanaBuzz, 1w) Issue 28

Post Syndicated from Blogs on Grafana Labs Blog original https://grafana.com/blog/2018/01/05/timeshiftgrafanabuzz-1w-issue-28/

Happy new year! Grafana Labs is getting back in the swing of things after taking some time off to celebrate 2017, and spending time with family and friends. We’re diligently working on the new Grafana v5.0 release (planning v5.0 beta release by end of January), which includes a ton of new features, a new layout engine, and a polished UI. We’d love to hear your feedback!


Latest Stable Release

Grafana 4.6.3 is now available. Latest bugfixes include:

  • Gzip: Fixes bug Gravatar images when gzip was enabled #5952
  • Alert list: Now shows alert state changes even after adding manual annotations on dashboard #99513
  • Alerting: Fixes bug where rules evaluated as firing when all conditions was false and using OR operator. #93183
  • Cloudwatch: CloudWatch no longer display metrics’ default alias #101514, thx @mtanda

Download Grafana 4.6.3 Now


From the Blogosphere

Why Observability Matters – Now and in the Future: Our own Carl Bergquist teamed up with Neil Gehani, Director of Product at Weaveworks to discuss best practices on how to get started with monitoring your application and infrastructure. This video focuses on modern containerized applications instrumented to use Prometheus to generate metrics and Grafana to visualize them.

How to Install and Secure Grafana on Ubuntu 16.04: In this tutorial, you’ll learn how to install and secure Grafana with a SSL certificate and a Nginx reverse proxy, then you’ll modify Grafana’s default settings for even tighter security.

Monitoring Informix with Grafana: Ben walks us through how to use Grafana to visualize data from IBM Informix and offers a practical demonstration using Docker containers. He also talks about his philosophy of sharing dashboards across teams, important metrics to collect, and how he would like to improve his monitoring stack.

Monitor your hosts with Glances + InfluxDB + Grafana: Glances is a cross-platform system monitoring tool written in Python. This article takes you step by step through the pieces of the stack, installation, confirguration and provides a sample dashboard to get you up and running.


GrafanaCon Tickets are Going Fast!

Lock in your seat for GrafanaCon EU while there are still tickets avaialable! Join us March 1-2, 2018 in Amsterdam for 2 days of talks centered around Grafana and the surrounding monitoring ecosystem including Graphite, Prometheus, InfluxData, Elasticsearch, Kubernetes, and more.

We have some exciting talks lined up from Google, CERN, Bloomberg, eBay, Red Hat, Tinder, Fastly, Automattic, Prometheus, InfluxData, Percona and more! You can see the full list of speakers below, but be sure to get your ticket now.

Get Your Ticket Now

GrafanaCon EU will feature talks from:

“Google Bigtable”
Misha Brukman
PROJECT MANAGER,
GOOGLE CLOUD
GOOGLE

“Monitoring at Bloomberg”
Stig Sorensen
HEAD OF TELEMETRY
BLOOMBERG

“Monitoring at Bloomberg”
Sean Hanson
SOFTWARE DEVELOPER
BLOOMBERG

“Monitoring Tinder’s Billions of Swipes with Grafana”
Utkarsh Bhatnagar
SR. SOFTWARE ENGINEER
TINDER

“Grafana at CERN”
Borja Garrido
PROJECT ASSOCIATE
CERN

“Monitoring the Huge Scale at Automattic”
Abhishek Gahlot
SOFTWARE ENGINEER
Automattic

“Real-time Engagement During the 2016 US Presidential Election”
Anna MacLachlan
CONTENT MARKETING MANAGER
Fastly

“Real-time Engagement During the 2016 US Presidential Election”
Gerlando Piro
FRONT END DEVELOPER
Fastly

“Grafana v5 and the Future”
Torkel Odegaard
CREATOR | PROJECT LEAD
GRAFANA

“Prometheus for Monitoring Metrics”
Brian Brazil
FOUNDER
ROBUST PERCEPTION

“What We Learned Integrating Grafana with Prometheus”
Peter Zaitsev
CO-FOUNDER | CEO
PERCONA

“The Biz of Grafana”
Raj Dutt
CO-FOUNDER | CEO
GRAFANA LABS

“What’s New In Graphite”
Dan Cech
DIR, PLATFORM SERVICES
GRAFANA LABS

“The Design of IFQL, the New Influx Functional Query Language”
Paul Dix
CO-FOUNTER | CTO
INFLUXDATA

“Writing Grafana Dashboards with Jsonnet”
Julien Pivotto
OPEN SOURCE CONSULTANT
INUITS

“Monitoring AI Platform at eBay”
Deepak Vasthimal
MTS-2 SOFTWARE ENGINEER
EBAY

“Running a Power Plant with Grafana”
Ryan McKinley
DEVELOPER
NATEL ENERGY

“Performance Metrics and User Experience: A “Tinder” Experience”
Susanne Greiner
DATA SCIENTIST
WÜRTH PHOENIX S.R.L.

“Analyzing Performance of OpenStack with Grafana Dashboards”
Alex Krzos
SENIOR SOFTWARE ENGINEER
RED HAT INC.

“Storage Monitoring at Shell Upstream”
Arie Jan Kraai
STORAGE ENGINEER
SHELL TECHNICAL LANDSCAPE SERVICE

“The RED Method: How To Instrument Your Services”
Tom Wilkie
FOUNDER
KAUSAL

“Grafana Usage in the Quality Assurance Process”
Andrejs Kalnacs
LEAD SOFTWARE DEVELOPER IN TEST
EVOLUTION GAMING

“Using Prometheus and Grafana for Monitoring my Power Usage”
Erwin de Keijzer
LINUX ENGINEER
SNOW BV

“Weather, Power & Market Forecasts with Grafana”
Max von Roden
DATA SCIENTIST
ENERGY WEATHER

“Weather, Power & Market Forecasts with Grafana”
Steffen Knott
HEAD OF IT
ENERGY WEATHER

“Inherited Technical Debt – A Tale of Overcoming Enterprise Inertia”
Jordan J. Hamel
HEAD OF MONITORING PLATFORMS
AMGEN

“Grafanalib: Dashboards as Code”
Jonathan Lange
VP OF ENGINEERING
WEAVEWORKS

“The Journey of Shifting the MQTT Broker HiveMQ to Kubernetes”
Arnold Bechtoldt
SENIOR SYSTEMS ENGINEER
INOVEX

“Graphs Tell Stories”
Blerim Sheqa
SENIOR DEVELOPER
NETWAYS

[email protected] or How to Store Millions of Metrics per Second”
Vladimir Smirnov
SYSTEM ADMINISTRATOR
Booking.com


Upcoming Events:

In between code pushes we like to speak at, sponsor and attend all kinds of conferences and meetups. We also like to make sure we mention other Grafana-related events happening all over the world. If you’re putting on just such an event, let us know and we’ll list it here.

FOSDEM | Brussels, Belgium – Feb 3-4, 2018: FOSDEM is a free developer conference where thousands of developers of free and open source software gather to share ideas and technology. There is no need to register; all are welcome.

Jfokus | Stockholm, Sweden – Feb 5-7, 2018:
Carl Bergquist – Quickie: Monitoring? Not OPS Problem

Why should we monitor our system? Why can’t we just rely on the operations team anymore? They use to be able to do that. What’s currently changing? Presentation content: – Why do we monitor our system – How did it use to work? – Whats changing – Why do we need to shift focus – Everyone should be on call. – Resilience is the goal (Best way of having someone care about quality is to make them responsible).

Register Now

Jfokus | Stockholm, Sweden – Feb 5-7, 2018:
Leonard Gram – Presentation: DevOps Deconstructed

What’s a Site Reliability Engineer and how’s that role different from the DevOps engineer my boss wants to hire? I really don’t want to be on call, should I? Is Docker the right place for my code or am I better of just going straight to Serverless? And why should I care about any of it? I’ll try to answer some of these questions while looking at what DevOps really is about and how commodisation of servers through “the cloud” ties into it all. This session will be an opinionated piece from a developer who’s been on-call for the past 6 years and would like to convince you to do the same, at least once.

Register Now

Tweet of the Week

We scour Twitter each week to find an interesting/beautiful dashboard and show it off! #monitoringLove

Awesome! Let us know if you have any questions – we’re happy to help out. We also have a bunch of screencasts to help you get going.


Grafana Labs is Hiring!

We are passionate about open source software and thrive on tackling complex challenges to build the future. We ship code from every corner of the globe and love working with the community. If this sounds exciting, you’re in luck – WE’RE HIRING!

Check out our Open Positions


How are we doing?

That’s a wrap! Let us know what you think about timeShift. Submit a comment on this article below, or post something at our community forum. See you next year!

Follow us on Twitter, like us on Facebook, and join the Grafana Labs community.

The Raspberry Pi PiServer tool

Post Syndicated from Gordon Hollingworth original https://www.raspberrypi.org/blog/piserver/

As Simon mentioned in his recent blog post about Raspbian Stretch, we have developed a new piece of software called PiServer. Use this tool to easily set up a network of client Raspberry Pis connected to a single x86-based server via Ethernet. With PiServer, you don’t need SD cards, you can control all clients via the server, and you can add and configure user accounts — it’s ideal for the classroom, your home, or an industrial setting.

PiServer diagram

Client? Server?

Before I go into more detail, let me quickly explain some terms.

  • Server — the server is the computer that provides the file system, boot files, and password authentication to the client(s)
  • Client — a client is a computer that retrieves boot files from the server over the network, and then uses a file system the server has shared. More than one client can connect to a server, but all clients use the same file system.
  • User – a user is a user name/password combination that allows someone to log into a client to access the file system on the server. Any user can log into any client with their credentials, and will always see the same server and share the same file system. Users do not have sudo capability on a client, meaning they cannot make significant changes to the file system and software.

I see no SD cards

Last year we described how the Raspberry Pi 3 Model B can be booted without an SD card over an Ethernet network from another computer (the server). This is called network booting or PXE (pronounced ‘pixie’) booting.

Why would you want to do this?

  • A client computer (the Raspberry Pi) doesn’t need any permanent storage (an SD card) to boot.
  • You can network a large number of clients to one server, and all clients are exactly the same. If you log into one of the clients, you will see the same file system as if you logged into any other client.
  • The server can be run on an x86 system, which means you get to take advantage of the performance, network, and disk speed on the server.

Sounds great, right? Of course, for the less technical, creating such a network is very difficult. For example, there’s setting up all the required DHCP and TFTP servers, and making sure they behave nicely with the rest of the network. If you get this wrong, you can break your entire network.

PiServer to the rescue

To make network booting easy, I thought it would be nice to develop an application which did everything for you. Let me introduce: PiServer!

PiServer has the following functionalities:

  • It automatically detects Raspberry Pis trying to network boot, so you don’t have to work out their Ethernet addresses.
  • It sets up a DHCP server — the thing inside the router that gives all network devices an IP address — either in proxy mode or in full IP mode. No matter the mode, the DHCP server will only reply to the Raspberry Pis you have specified, which is important for network safety.
  • It creates user names and passwords for the server. This is great for a classroom full of Pis: just set up all the users beforehand, and everyone gets to log in with their passwords and keep all their work in a central place. Moreover, users cannot change the software, so educators have control over which programs their learners can use.
  • It uses a slightly altered Raspbian build which allows separation of temporary spaces, doesn’t have the default ‘pi’ user, and has LDAP enabled for log-in.

What can I do with PiServer?

Serve a whole classroom of Pis

In a classroom, PiServer allows all files for lessons or projects to be stored on a central x86-based computer. Each user can have their own account, and any files they create are also stored on the server. Moreover, the networked Pis doesn’t need to be connected to the internet. The teacher has centralised control over all Pis, and all Pis are user-agnostic, meaning there’s no need to match a person with a computer or an SD card.

Build a home server

PiServer could be used in the home to serve file systems for all Raspberry Pis around the house — either a single common Raspbian file system for all Pis or a different operating system for each. Hopefully, our extensive OS suppliers will provide suitable build files in future.

Use it as a controller for networked Pis

In an industrial scenario, it is possible to use PiServer to develop a network of Raspberry Pis (maybe even using Power over Ethernet (PoE)) such that the control software for each Pi is stored remotely on a server. This enables easy remote control and provisioning of the Pis from a central repository.

How to use PiServer

The client machines

So that you can use a Pi as a client, you need to enable network booting on it. Power it up using an SD card with a Raspbian Lite image, and open a terminal window. Type in

echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt

and press Return. This adds the line program_usb_boot_mode=1 to the end of the config.txt file in /boot. Now power the Pi down and remove the SD card. The next time you connect the Pi to a power source, you will be able to network boot it.

The server machine

As a server, you will need an x86 computer on which you can install x86 Debian Stretch. Refer to Simon’s blog post for additional information on this. It is possible to use a Raspberry Pi to serve to the client Pis, but the file system will be slower, especially at boot time.

Make sure your server has a good amount of disk space available for the file system — in general, we recommend at least 16Gb SD cards for Raspberry Pis. The whole client file system is stored locally on the server, so the disk space requirement is fairly significant.

Next, start PiServer by clicking on the start icon and then clicking Preferences > PiServer. This will open a graphical user interface — the wizard — that will walk you through setting up your network. Skip the introduction screen, and you should see a screen looking like this:

PiServer GUI screenshot

If you’ve enabled network booting on the client Pis and they are connected to a power source, their MAC addresses will automatically appear in the table shown above. When you have added all your Pis, click Next.

PiServer GUI screenshot

On the Add users screen, you can set up users on your server. These are pairs of user names and passwords that will be valid for logging into the client Raspberry Pis. Don’t worry, you can add more users at any point. Click Next again when you’re done.

PiServer GUI screenshot

The Add software screen allows you to select the operating system you want to run on the attached Pis. (You’ll have the option to assign an operating system to each client individually in the setting after the wizard has finished its job.) There are some automatically populated operating systems, such as Raspbian and Raspbian Lite. Hopefully, we’ll add more in due course. You can also provide your own operating system from a local file, or install it from a URL. For further information about how these operating system images are created, have a look at the scripts in /var/lib/piserver/scripts.

Once you’re done, click Next again. The wizard will then install the necessary components and the operating systems you’ve chosen. This will take a little time, so grab a coffee (or decaffeinated drink of your choice).

When the installation process is finished, PiServer is up and running — all you need to do is reboot the Pis to get them to run from the server.

Shooting troubles

If you have trouble getting clients connected to your network, there are a fewthings you can do to debug:

  1. If some clients are connecting but others are not, check whether you’ve enabled the network booting mode on the Pis that give you issues. To do that, plug an Ethernet cable into the Pi (with the SD card removed) — the LEDs on the Pi and connector should turn on. If that doesn’t happen, you’ll need to follow the instructions above to boot the Pi and edit its /boot/config.txt file.
  2. If you can’t connect to any clients, check whether your network is suitable: format an SD card, and copy bootcode.bin from /boot on a standard Raspbian image onto it. Plug the card into a client Pi, and check whether it appears as a new MAC address in the PiServer GUI. If it does, then the problem is a known issue, and you can head to our forums to ask for advice about it (the network booting code has a couple of problems which we’re already aware of). For a temporary fix, you can clone the SD card on which bootcode.bin is stored for all your clients.

If neither of these things fix your problem, our forums are the place to find help — there’s a host of people there who’ve got PiServer working. If you’re sure you have identified a problem that hasn’t been addressed on the forums, or if you have a request for a functionality, then please add it to the GitHub issues.

The post The Raspberry Pi PiServer tool appeared first on Raspberry Pi.

New – Amazon CloudWatch Agent with AWS Systems Manager Integration – Unified Metrics & Log Collection for Linux & Windows

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/new-amazon-cloudwatch-agent-with-aws-systems-manager-integration-unified-metrics-log-collection-for-linux-windows/

In the past I’ve talked about several agents, deaemons, and scripts that you could use to collect system metrics and log files for your Windows and Linux instances and on-premise services and publish them to Amazon CloudWatch. The data collected by this somewhat disparate collection of tools gave you visibility into the status and behavior of your compute resources, along with the power to take action when a value goes out of range and indicates a potential issue. You can graph any desired metrics on CloudWatch Dashboards, initiate actions via CloudWatch Alarms, and search CloudWatch Logs to find error messages, while taking advantage of our support for custom high-resolution metrics.

New Unified Agent
Today we are taking a nice step forward and launching a new, unified CloudWatch Agent. It runs in the cloud and on-premises, on Linux and Windows instances and servers, and handles metrics and log files. You can deploy it using AWS Systems Manager (SSM) Run Command, SSM State Manager, or from the CLI. Here are some of the most important features:

Single Agent – A single agent now collects both metrics and logs. This simplifies the setup process and reduces complexity.

Cross-Platform / Cross-Environment – The new agent runs in the cloud and on-premises, on 64-bit Linux and 64-bit Windows, and includes HTTP proxy server support.

Configurable – The new agent captures the most useful system metrics automatically. It can be configured to collect hundreds of others, including fine-grained metrics on sub-resources such as CPU threads, mounted filesystems, and network interfaces.

CloudWatch-Friendly – The new agent supports standard 1-minute metrics and the newer 1-second high-resolution metrics. It automatically includes EC2 dimensions such as Instance Id, Image Id, and Auto Scaling Group Name, and also supports the use of custom dimensions. All of the dimensions can be used for custom aggregation across Auto Scaling Groups, applications, and so forth.

Migration – You can easily migrate existing AWS SSM and EC2Config configurations for use with the new agent.

Installing the Agent
The CloudWatch Agent uses an IAM role when running on an EC2 instance, and an IAM user when running on an on-premises server. The role or the user must include the AmazonSSMFullAccess and AmazonEC2ReadOnlyAccess policies. Here’s my role:

I can easily add it to a running instance (this is a relatively new and very handy EC2 feature):

The SSM Agent is already running on my instance. If it wasn’t, I would follow the steps in Installing and Configuring SSM Agent to set it up.

Next, I install the CloudWatch Agent using the AWS Systems Manager:

This takes just a few seconds. Now I can use a simple wizard to set up the configuration file for the agent:

The wizard also lets me set up the log files to be monitored:

The wizard generates a JSON-format config file and stores it on the instance. It also offers me the option to upload the file to my Parameter Store so that I can deploy it to my other instances (I can also do fine-grained customization of the metrics and log collection configuration by editing the file):

Now I can start the CloudWatch Agent using Run Command, supplying the name of my configuration in the Parameter Store:

This runs in a few seconds and the agent begins to publish metrics right away. As I mentioned earlier, the agent can publish fine-grained metrics on the resources inside of or attached to an instance. For example, here are the metrics for each filesystem:

There’s a separate log stream for each monitored log file on each instance:

I can view and search it, just like I can do for any other log stream:

Now Available
The new CloudWatch Agent is available now and you can start using it today in all public AWS Regions, with AWS GovCloud (US) and the Regions in China to follow.

There’s no charge for the agent; you pay the usual CloudWatch prices for logs and custom metrics.

Jeff;

timeShift(GrafanaBuzz, 1w) Issue 25

Post Syndicated from Blogs on Grafana Labs Blog original https://grafana.com/blog/2017/12/08/timeshiftgrafanabuzz-1w-issue-25/

Welcome to TimeShift

This week, a few of us from Grafana Labs, along with 4,000 of our closest friends, headed down to chilly Austin, TX for KubeCon + CloudNativeCon North America 2017. We got to see a number of great talks and were thrilled to see Grafana make appearances in some of the presentations. We were also a sponsor of the conference and handed out a ton of swag (we overnighted some of our custom Grafana scarves, which came in handy for Thursday’s snow).

We also announced Grafana Labs has joined the Cloud Native Computing Foundation as a Silver member! We’re excited to share our expertise in time series data visualization and open source software with the CNCF community.


Latest Release

Grafana 4.6.2 is available and includes some bug fixes:

  • Prometheus: Fixes bug with new Prometheus alerts in Grafana. Make sure to download this version if you’re using Prometheus for alerting. More details in the issue. #9777
  • Color picker: Bug after using textbox input field to change/paste color string #9769
  • Cloudwatch: build using golang 1.9.2 #9667, thanks @mtanda
  • Heatmap: Fixed tooltip for “time series buckets” mode #9332
  • InfluxDB: Fixed query editor issue when using > or < operators in WHERE clause #9871

Download Grafana 4.6.2 Now


From the Blogosphere

Grafana Labs Joins the CNCF: Grafana Labs has officially joined the Cloud Native Computing Foundation (CNCF). We look forward to working with the CNCF community to democratize metrics and help unify traditionally disparate information.

Automating Web Performance Regression Alerts: Peter and his team needed a faster and easier way to find web performance regressions at the Wikimedia Foundation. Grafana 4’s alerting features were exactly what they needed. This post covers their journey on setting up alerts for both RUM and synthetic testing and shares the alerts they’ve set up on their dashboards.

How To Install Grafana on Ubuntu 17.10: As you probably guessed from the title, this article walks you through installing and configuring Grafana in the latest version of Ubuntu (or earlier releases). It also covers installing plugins using the Grafana CLI tool.

Prometheus: Starting the Server with Alertmanager, cAdvisor and Grafana: Learn how to monitor Docker from scratch using cAdvisor, Prometheus and Grafana in this detailed, step-by-step walkthrough.

Monitoring Java EE Servers with Prometheus and Payara: In this screencast, Adam uses firehose; a Java EE 7+ metrics gateway for Prometheus, to convert the JSON output into Prometheus statistics and visualizes the data in Grafana.

Monitoring Spark Streaming with InfluxDB and Grafana: This article focuses on how to monitor Apache Spark Streaming applications with InfluxDB and Grafana at scale.


GrafanaCon EU, March 1-2, 2018

We are currently reaching out to everyone who submitted a talk to GrafanaCon and will soon publish the final schedule at grafanacon.org.

Join us March 1-2, 2018 in Amsterdam for 2 days of talks centered around Grafana and the surrounding monitoring ecosystem including Graphite, Prometheus, InfluxData, Elasticsearch, Kubernetes, and more.

Get Your Ticket Now


Grafana Plugins

Lots of plugin updates and a new OpenNMS Helm App plugin to announce! To install or update any plugin in an on-prem Grafana instance, use the Grafana-cli tool, or install and update with 1 click on Hosted Grafana.

NEW PLUGIN

OpenNMS Helm App – The new OpenNMS Helm App plugin replaces the old OpenNMS data source. Helm allows users to create flexible dashboards using both fault management (FM) and performance management (PM) data from OpenNMS® Horizon™ and/or OpenNMS® Meridian™. The old data source is now deprecated.


Install Now

UPDATED PLUGIN

PNP Data Source – This data source plugin (that uses PNP4Nagios to access RRD files) received a small, but important update that fixes template query parsing.


Update

UPDATED PLUGIN

Vonage Status Panel – The latest version of the Status Panel comes with a number of small fixes and changes. Below are a few of the enhancements:

  • Threshold settings – removed Show Always option, and replaced it with 2 options:
    • Display Alias – Select when to show the metric alias.
    • Display Value – Select when to show the metric value.
  • Text format configuration (bold / italic) for warning / critical / disabled states.
  • Option to change the corner radius of the panel. Now you can change the panel’s shape to have rounded corners.

Update

UPDATED PLUGIN

Google Calendar Plugin – This plugin received a small update, so be sure to install version 1.0.4.


Update

UPDATED PLUGIN

Carpet Plot Panel – The Carpet Plot Panel received a fix for IE 11, and also added the ability to choose custom colors.


Update


Upcoming Events:

In between code pushes we like to speak at, sponsor and attend all kinds of conferences and meetups. We also like to make sure we mention other Grafana-related events happening all over the world. If you’re putting on just such an event, let us know and we’ll list it here.

Docker Meetup @ Tuenti | Madrid, Spain – Dec 12, 2017: Javier Provecho: Intro to Metrics with Swarm, Prometheus and Grafana

Learn how to gain visibility in real time for your micro services. We’ll cover how to deploy a Prometheus server with persistence and Grafana, how to enable metrics endpoints for various service types (docker daemon, traefik proxy and postgres) and how to scrape, visualize and set up alarms based on those metrics.

RSVP

Grafana Lyon Meetup n ° 2 | Lyon, France – Dec 14, 2017: This meetup will cover some of the latest innovations in Grafana and discussion about automation. Also, free beer and chips, so – of course you’re going!

RSVP

FOSDEM | Brussels, Belgium – Feb 3-4, 2018: FOSDEM is a free developer conference where thousands of developers of free and open source software gather to share ideas and technology. Carl Bergquist is managing the Cloud and Monitoring Devroom, and we’ve heard there were some great talks submitted. There is no need to register; all are welcome.


Tweet of the Week

We scour Twitter each week to find an interesting/beautiful dashboard and show it off! #monitoringLove

We were thrilled to see our dashboards bigger than life at KubeCon + CloudNativeCon this week. Thanks for snapping a photo and sharing!


Grafana Labs is Hiring!

We are passionate about open source software and thrive on tackling complex challenges to build the future. We ship code from every corner of the globe and love working with the community. If this sounds exciting, you’re in luck – WE’RE HIRING!

Check out our Open Positions


How are we doing?

Hard to believe this is the 25th issue of Timeshift! I have a blast writing these roundups, but Let me know what you think. Submit a comment on this article below, or post something at our community forum. Find an article I haven’t included? Send it my way. Help us make timeShift better!

Follow us on Twitter, like us on Facebook, and join the Grafana Labs community.

timeShift(GrafanaBuzz, 1w) Issue 24

Post Syndicated from Blogs on Grafana Labs Blog original https://grafana.com/blog/2017/12/01/timeshiftgrafanabuzz-1w-issue-24/

Welcome to TimeShift

It’s hard to believe it’s already December. Here at Grafana Labs we’ve been spending a lot of time working on new features and enhancements for Grafana v5, and finalizing our selections for GrafanaCon EU. This week we have some interesting articles to share and a number of plugin updates. Enjoy!


Latest Release

Grafana 4.6.2 is now available and includes some bug fixes:

  • Prometheus: Fixes bug with new Prometheus alerts in Grafana. Make sure to download this version if you’re using Prometheus for alerting. More details in the issue. #9777
  • Color picker: Bug after using textbox input field to change/paste color string #9769
  • Cloudwatch: build using golang 1.9.2 #9667, thanks @mtanda
  • Heatmap: Fixed tooltip for “time series buckets” mode #9332
  • InfluxDB: Fixed query editor issue when using > or < operators in WHERE clause #9871

Download Grafana 4.6.2 Now


From the Blogosphere

Monitoring Camel with Prometheus in Red Hat OpenShift: This in-depth walk-through will show you how to build an Apache Camel application from scratch, deploy it in a Kubernetes environment, gather metrics using Prometheus and display them in Grafana.

How to run Grafana with DeviceHive: We see more and more examples of people using Grafana in IoT. This article discusses how to gather data from the IoT platform, DeviceHive, and build useful dashboards.

How to Install Grafana on Linux Servers: Pretty self-explanatory, but this tutorial walks you installing Grafana on Ubuntu 16.04 and CentOS 7. After installation, it covers configuration and plugin installation. This is the first article in an upcoming series about Grafana.

Monitoring your AKS cluster with Grafana: It’s important to know how your application is performing regardless of where it lives; the same applies to Kubernetes. This article focuses on aggregating data from Kubernetes with Heapster and feeding it to a backend for Grafana to visualize.

CoinStatistics: With the price of Bitcoin skyrocketing, more and more people are interested in cryptocurrencies. This is a cool dashboard that has a lot of stats about popular cryptocurrencies, and has a calculator to let you know when you can buy that lambo.

Using OpenNTI As A Collector For Streaming Telemetry From Juniper Devices: Part 1: This series will serve as a quick start guide for getting up and running with streaming real-time telemetry data from Juniper devices. This first article covers some high-level concepts and installation, while part 2 covers configuration options.

How to Get Metrics for Advance Alerting to Prevent Trouble: What good is performance monitoring if you’re never told when something has gone wrong? This article suggests ways to be more proactive to prevent issues and avoid the scramble to troubleshoot issues.

Thoughtworks: Technology Radar: We got a shout-out in the latest Technology Radar in the Tools section, as the dashboard visualization tool of choice for Prometheus!


GrafanaCon Tickets are Going Fast

Tickets are going fast for GrafanaCon EU, but we still have a seat reserved for you. Join us March 1-2, 2018 in Amsterdam for 2 days of talks centered around Grafana and the surrounding monitoring ecosystem including Graphite, Prometheus, InfluxData, Elasticsearch, Kubernetes, and more.

Get Your Ticket Now


Grafana Plugins

We have a number of plugin updates to highlight this week. Authors improve plugins regularly to fix bugs and improve performance, so it’s important to keep your plugins up to date. We’ve made updating easy; for on-prem Grafana, use the Grafana-cli tool, or update with 1 click if you’re using Hosted Grafana.

UPDATED PLUGIN

Clickhouse Data Source – The Clickhouse Data Source received a substantial update this week. It now has support for Ace Editor, which has a reformatting function for the query editor that automatically formats your sql. If you’re using Clickhouse then you should also have a look at CHProxy – see the plugin readme for more details.


Update

UPDATED PLUGIN

Influx Admin Panel – This panel received a number of small fixes. A new version will be coming soon with some new features.

Some of the changes (see the release notes) for more details):

  • Fix issue always showing query results
  • When there is only one row, swap rows/cols (ie: SHOW DIAGNOSTICS)
  • Improve auto-refresh behavior
  • Show ‘message’ response. (ie: please use POST)
  • Fix query time sorting
  • Show ‘status’ field (killed, etc)

Update

UPDATED PLUGIN

Gnocchi Data Source – The latest version of the Gnocchi Data Source adds support for dynamic aggregations.


Update

UPDATED PLUGINS

BT Plugins – All of the BT panel plugins received updates this week.


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Object models

Post Syndicated from Eevee original https://eev.ee/blog/2017/11/28/object-models/

Anonymous asks, with dollars:

More about programming languages!

Well then!

I’ve written before about what I think objects are: state and behavior, which in practice mostly means method calls.

I suspect that the popular impression of what objects are, and also how they should work, comes from whatever C++ and Java happen to do. From that point of view, the whole post above is probably nonsense. If the baseline notion of “object” is a rigid definition woven tightly into the design of two massively popular languages, then it doesn’t even make sense to talk about what “object” should mean — it does mean the features of those languages, and cannot possibly mean anything else.

I think that’s a shame! It piles a lot of baggage onto a fairly simple idea. Polymorphism, for example, has nothing to do with objects — it’s an escape hatch for static type systems. Inheritance isn’t the only way to reuse code between objects, but it’s the easiest and fastest one, so it’s what we get. Frankly, it’s much closer to a speed tradeoff than a fundamental part of the concept.

We could do with more experimentation around how objects work, but that’s impossible in the languages most commonly thought of as object-oriented.

Here, then, is a (very) brief run through the inner workings of objects in four very dynamic languages. I don’t think I really appreciated objects until I’d spent some time with Python, and I hope this can help someone else whet their own appetite.

Python 3

Of the four languages I’m going to touch on, Python will look the most familiar to the Java and C++ crowd. For starters, it actually has a class construct.

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class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __neg__(self):
        return Vector(-self.x, -self.y)

    def __div__(self, denom):
        return Vector(self.x / denom, self.y / denom)

    @property
    def magnitude(self):
        return (self.x ** 2 + self.y ** 2) ** 0.5

    def normalized(self):
        return self / self.magnitude

The __init__ method is an initializer, which is like a constructor but named differently (because the object already exists in a usable form by the time the initializer is called). Operator overloading is done by implementing methods with other special __dunder__ names. Properties can be created with @property, where the @ is syntax for applying a wrapper function to a function as it’s defined. You can do inheritance, even multiply:

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class Foo(A, B, C):
    def bar(self, x, y, z):
        # do some stuff
        super().bar(x, y, z)

Cool, a very traditional object model.

Except… for some details.

Some details

For one, Python objects don’t have a fixed layout. Code both inside and outside the class can add or remove whatever attributes they want from whatever object they want. The underlying storage is just a dict, Python’s mapping type. (Or, rather, something like one. Also, it’s possible to change, which will probably be the case for everything I say here.)

If you create some attributes at the class level, you’ll start to get a peek behind the curtains:

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class Foo:
    values = []

    def add_value(self, value):
        self.values.append(value)

a = Foo()
b = Foo()
a.add_value('a')
print(a.values)  # ['a']
b.add_value('b')
print(b.values)  # ['a', 'b']

The [] assigned to values isn’t a default assigned to each object. In fact, the individual objects don’t know about it at all! You can use vars(a) to get at the underlying storage dict, and you won’t see a values entry in there anywhere.

Instead, values lives on the class, which is a value (and thus an object) in its own right. When Python is asked for self.values, it checks to see if self has a values attribute; in this case, it doesn’t, so Python keeps going and asks the class for one.

Python’s object model is secretly prototypical — a class acts as a prototype, as a shared set of fallback values, for its objects.

In fact, this is also how method calls work! They aren’t syntactically special at all, which you can see by separating the attribute lookup from the call.

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print("abc".startswith("a"))  # True
meth = "abc".startswith
print(meth("a"))  # True

Reading obj.method looks for a method attribute; if there isn’t one on obj, Python checks the class. Here, it finds one: it’s a function from the class body.

Ah, but wait! In the code I just showed, meth seems to “know” the object it came from, so it can’t just be a plain function. If you inspect the resulting value, it claims to be a “bound method” or “built-in method” rather than a function, too. Something funny is going on here, and that funny something is the descriptor protocol.

Descriptors

Python allows attributes to implement their own custom behavior when read from or written to. Such an attribute is called a descriptor. I’ve written about them before, but here’s a quick overview.

If Python looks up an attribute, finds it in a class, and the value it gets has a __get__ method… then instead of using that value, Python will use the return value of its __get__ method.

The @property decorator works this way. The magnitude property in my original example was shorthand for doing this:

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class MagnitudeDescriptor:
    def __get__(self, instance, owner):
        if instance is None:
            return self
        return (instance.x ** 2 + instance.y ** 2) ** 0.5

class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    magnitude = MagnitudeDescriptor()

When you ask for somevec.magnitude, Python checks somevec but doesn’t find magnitude, so it consults the class instead. The class does have a magnitude, and it’s a value with a __get__ method, so Python calls that method and somevec.magnitude evaluates to its return value. (The instance is None check is because __get__ is called even if you get the descriptor directly from the class via Vector.magnitude. A descriptor intended to work on instances can’t do anything useful in that case, so the convention is to return the descriptor itself.)

You can also intercept attempts to write to or delete an attribute, and do absolutely whatever you want instead. But note that, similar to operating overloading in Python, the descriptor must be on a class; you can’t just slap one on an arbitrary object and have it work.

This brings me right around to how “bound methods” actually work. Functions are descriptors! The function type implements __get__, and when a function is retrieved from a class via an instance, that __get__ bundles the function and the instance together into a tiny bound method object. It’s essentially:

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class FunctionType:
    def __get__(self, instance, owner):
        if instance is None:
            return self
        return functools.partial(self, instance)

The self passed as the first argument to methods is not special or magical in any way. It’s built out of a few simple pieces that are also readily accessible to Python code.

Note also that because obj.method() is just an attribute lookup and a call, Python doesn’t actually care whether method is a method on the class or just some callable thing on the object. You won’t get the auto-self behavior if it’s on the object, but otherwise there’s no difference.

More attribute access, and the interesting part

Descriptors are one of several ways to customize attribute access. Classes can implement __getattr__ to intervene when an attribute isn’t found on an object; __setattr__ and __delattr__ to intervene when any attribute is set or deleted; and __getattribute__ to implement unconditional attribute access. (That last one is a fantastic way to create accidental recursion, since any attribute access you do within __getattribute__ will of course call __getattribute__ again.)

Here’s what I really love about Python. It might seem like a magical special case that descriptors only work on classes, but it really isn’t. You could implement exactly the same behavior yourself, in pure Python, using only the things I’ve just told you about. Classes are themselves objects, remember, and they are instances of type, so the reason descriptors only work on classes is that type effectively does this:

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class type:
    def __getattribute__(self, name):
        value = super().__getattribute__(name)
        # like all op overloads, __get__ must be on the type, not the instance
        ty = type(value)
        if hasattr(ty, '__get__'):
            # it's a descriptor!  this is a class access so there is no instance
            return ty.__get__(value, None, self)
        else:
            return value

You can even trivially prove to yourself that this is what’s going on by skipping over types behavior:

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class Descriptor:
    def __get__(self, instance, owner):
        print('called!')

class Foo:
    bar = Descriptor()

Foo.bar  # called!
type.__getattribute__(Foo, 'bar')  # called!
object.__getattribute__(Foo, 'bar')  # ...

And that’s not all! The mysterious super function, used to exhaustively traverse superclass method calls even in the face of diamond inheritance, can also be expressed in pure Python using these primitives. You could write your own superclass calling convention and use it exactly the same way as super.

This is one of the things I really like about Python. Very little of it is truly magical; virtually everything about the object model exists in the types rather than the language, which means virtually everything can be customized in pure Python.

Class creation and metaclasses

A very brief word on all of this stuff, since I could talk forever about Python and I have three other languages to get to.

The class block itself is fairly interesting. It looks like this:

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class Name(*bases, **kwargs):
    # code

I’ve said several times that classes are objects, and in fact the class block is one big pile of syntactic sugar for calling type(...) with some arguments to create a new type object.

The Python documentation has a remarkably detailed description of this process, but the gist is:

  • Python determines the type of the new class — the metaclass — by looking for a metaclass keyword argument. If there isn’t one, Python uses the “lowest” type among the provided base classes. (If you’re not doing anything special, that’ll just be type, since every class inherits from object and object is an instance of type.)

  • Python executes the class body. It gets its own local scope, and any assignments or method definitions go into that scope.

  • Python now calls type(name, bases, attrs, **kwargs). The name is whatever was right after class; the bases are position arguments; and attrs is the class body’s local scope. (This is how methods and other class attributes end up on the class.) The brand new type is then assigned to Name.

Of course, you can mess with most of this. You can implement __prepare__ on a metaclass, for example, to use a custom mapping as storage for the local scope — including any reads, which allows for some interesting shenanigans. The only part you can’t really implement in pure Python is the scoping bit, which has a couple extra rules that make sense for classes. (In particular, functions defined within a class block don’t close over the class body; that would be nonsense.)

Object creation

Finally, there’s what actually happens when you create an object — including a class, which remember is just an invocation of type(...).

Calling Foo(...) is implemented as, well, a call. Any type can implement calls with the __call__ special method, and you’ll find that type itself does so. It looks something like this:

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# oh, a fun wrinkle that's hard to express in pure python: type is a class, so
# it's an instance of itself
class type:
    def __call__(self, *args, **kwargs):
        # remember, here 'self' is a CLASS, an instance of type.
        # __new__ is a true constructor: object.__new__ allocates storage
        # for a new blank object
        instance = self.__new__(self, *args, **kwargs)
        # you can return whatever you want from __new__ (!), and __init__
        # is only called on it if it's of the right type
        if isinstance(instance, self):
            instance.__init__(*args, **kwargs)
        return instance

Again, you can trivially confirm this by asking any type for its __call__ method. Assuming that type doesn’t implement __call__ itself, you’ll get back a bound version of types implementation.

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>>> list.__call__
<method-wrapper '__call__' of type object at 0x7fafb831a400>

You can thus implement __call__ in your own metaclass to completely change how subclasses are created — including skipping the creation altogether, if you like.

And… there’s a bunch of stuff I haven’t even touched on.

The Python philosophy

Python offers something that, on the surface, looks like a “traditional” class/object model. Under the hood, it acts more like a prototypical system, where failed attribute lookups simply defer to a superclass or metaclass.

The language also goes to almost superhuman lengths to expose all of its moving parts. Even the prototypical behavior is an implementation of __getattribute__ somewhere, which you are free to completely replace in your own types. Proxying and delegation are easy.

Also very nice is that these features “bundle” well, by which I mean a library author can do all manner of convoluted hijinks, and a consumer of that library doesn’t have to see any of it or understand how it works. You only need to inherit from a particular class (which has a metaclass), or use some descriptor as a decorator, or even learn any new syntax.

This meshes well with Python culture, which is pretty big on the principle of least surprise. These super-advanced features tend to be tightly confined to single simple features (like “makes a weak attribute“) or cordoned with DSLs (e.g., defining a form/struct/database table with a class body). In particular, I’ve never seen a metaclass in the wild implement its own __call__.

I have mixed feelings about that. It’s probably a good thing overall that the Python world shows such restraint, but I wonder if there are some very interesting possibilities we’re missing out on. I implemented a metaclass __call__ myself, just once, in an entity/component system that strove to minimize fuss when communicating between components. It never saw the light of day, but I enjoyed seeing some new things Python could do with the same relatively simple syntax. I wouldn’t mind seeing, say, an object model based on composition (with no inheritance) built atop Python’s primitives.

Lua

Lua doesn’t have an object model. Instead, it gives you a handful of very small primitives for building your own object model. This is pretty typical of Lua — it’s a very powerful language, but has been carefully constructed to be very small at the same time. I’ve never encountered anything else quite like it, and “but it starts indexing at 1!” really doesn’t do it justice.

The best way to demonstrate how objects work in Lua is to build some from scratch. We need two key features. The first is metatables, which bear a passing resemblance to Python’s metaclasses.

Tables and metatables

The table is Lua’s mapping type and its primary data structure. Keys can be any value other than nil. Lists are implemented as tables whose keys are consecutive integers starting from 1. Nothing terribly surprising. The dot operator is sugar for indexing with a string key.

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local t = { a = 1, b = 2 }
print(t['a'])  -- 1
print(t.b)  -- 2
t.c = 3
print(t['c'])  -- 3

A metatable is a table that can be associated with another value (usually another table) to change its behavior. For example, operator overloading is implemented by assigning a function to a special key in a metatable.

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local t = { a = 1, b = 2 }
--print(t + 0)  -- error: attempt to perform arithmetic on a table value

local mt = {
    __add = function(left, right)
        return 12
    end,
}
setmetatable(t, mt)
print(t + 0)  -- 12

Now, the interesting part: one of the special keys is __index, which is consulted when the base table is indexed by a key it doesn’t contain. Here’s a table that claims every key maps to itself.

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local t = {}
local mt = {
    __index = function(table, key)
        return key
    end,
}
setmetatable(t, mt)
print(t.foo)  -- foo
print(t.bar)  -- bar
print(t[3])  -- 3

__index doesn’t have to be a function, either. It can be yet another table, in which case that table is simply indexed with the key. If the key still doesn’t exist and that table has a metatable with an __index, the process repeats.

With this, it’s easy to have several unrelated tables that act as a single table. Call the base table an object, fill the __index table with functions and call it a class, and you have half of an object system. You can even get prototypical inheritance by chaining __indexes together.

At this point things are a little confusing, since we have at least three tables going on, so here’s a diagram. Keep in mind that Lua doesn’t actually have anything called an “object”, “class”, or “method” — those are just convenient nicknames for a particular structure we might build with Lua’s primitives.

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                    ╔═══════════╗        ...
                    ║ metatable ║         ║
                    ╟───────────╢   ┌─────╨───────────────────────┐
                    ║ __index   ╫───┤ lookup table ("superclass") │
                    ╚═══╦═══════╝   ├─────────────────────────────┤
  ╔═══════════╗         ║           │ some other method           ┼─── function() ... end
  ║ metatable ║         ║           └─────────────────────────────┘
  ╟───────────╢   ┌─────╨──────────────────┐
  ║ __index   ╫───┤ lookup table ("class") │
  ╚═══╦═══════╝   ├────────────────────────┤
      ║           │ some method            ┼─── function() ... end
      ║           └────────────────────────┘
┌─────╨─────────────────┐
│ base table ("object") │
└───────────────────────┘

Note that a metatable is not the same as a class; it defines behavior, not methods. Conversely, if you try to use a class directly as a metatable, it will probably not do much. (This is pretty different from e.g. Python, where operator overloads are just methods with funny names. One nice thing about the Lua approach is that you can keep interface-like functionality separate from methods, and avoid clogging up arbitrary objects’ namespaces. You could even use a dummy table as a key and completely avoid name collisions.)

Anyway, code!

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local class = {
    foo = function(a)
        print("foo got", a)
    end,
}
local mt = { __index = class }
-- setmetatable returns its first argument, so this is nice shorthand
local obj1 = setmetatable({}, mt)
local obj2 = setmetatable({}, mt)
obj1.foo(7)  -- foo got 7
obj2.foo(9)  -- foo got 9

Wait, wait, hang on. Didn’t I call these methods? How do they get at the object? Maybe Lua has a magical this variable?

Methods, sort of

Not quite, but this is where the other key feature comes in: method-call syntax. It’s the lightest touch of sugar, just enough to have method invocation.

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-- note the colon!
a:b(c, d, ...)

-- exactly equivalent to this
-- (except that `a` is only evaluated once)
a.b(a, c, d, ...)

-- which of course is really this
a["b"](a, c, d, ...)

Now we can write methods that actually do something.

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local class = {
    bar = function(self)
        print("our score is", self.score)
    end,
}
local mt = { __index = class }
local obj1 = setmetatable({ score = 13 }, mt)
local obj2 = setmetatable({ score = 25 }, mt)
obj1:bar()  -- our score is 13
obj2:bar()  -- our score is 25

And that’s all you need. Much like Python, methods and data live in the same namespace, and Lua doesn’t care whether obj:method() finds a function on obj or gets one from the metatable’s __index. Unlike Python, the function will be passed self either way, because self comes from the use of : rather than from the lookup behavior.

(Aside: strictly speaking, any Lua value can have a metatable — and if you try to index a non-table, Lua will always consult the metatable’s __index. Strings all have the string library as a metatable, so you can call methods on them: try ("%s %s"):format(1, 2). I don’t think Lua lets user code set the metatable for non-tables, so this isn’t that interesting, but if you’re writing Lua bindings from C then you can wrap your pointers in metatables to give them methods implemented in C.)

Bringing it all together

Of course, writing all this stuff every time is a little tedious and error-prone, so instead you might want to wrap it all up inside a little function. No problem.

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local function make_object(body)
    -- create a metatable
    local mt = { __index = body }
    -- create a base table to serve as the object itself
    local obj = setmetatable({}, mt)
    -- and, done
    return obj
end

-- you can leave off parens if you're only passing in 
local Dog = {
    -- this acts as a "default" value; if obj.barks is missing, __index will
    -- kick in and find this value on the class.  but if obj.barks is assigned
    -- to, it'll go in the object and shadow the value here.
    barks = 0,

    bark = function(self)
        self.barks = self.barks + 1
        print("woof!")
    end,
}

local mydog = make_object(Dog)
mydog:bark()  -- woof!
mydog:bark()  -- woof!
mydog:bark()  -- woof!
print(mydog.barks)  -- 3
print(Dog.barks)  -- 0

It works, but it’s fairly barebones. The nice thing is that you can extend it pretty much however you want. I won’t reproduce an entire serious object system here — lord knows there are enough of them floating around — but the implementation I have for my LÖVE games lets me do this:

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local Animal = Object:extend{
    cries = 0,
}

-- called automatically by Object
function Animal:init()
    print("whoops i couldn't think of anything interesting to put here")
end

-- this is just nice syntax for adding a first argument called 'self', then
-- assigning this function to Animal.cry
function Animal:cry()
    self.cries = self.cries + 1
end

local Cat = Animal:extend{}

function Cat:cry()
    print("meow!")
    Cat.__super.cry(self)
end

local cat = Cat()
cat:cry()  -- meow!
cat:cry()  -- meow!
print(cat.cries)  -- 2

When I say you can extend it however you want, I mean that. I could’ve implemented Python (2)-style super(Cat, self):cry() syntax; I just never got around to it. I could even make it work with multiple inheritance if I really wanted to — or I could go the complete opposite direction and only implement composition. I could implement descriptors, customizing the behavior of individual table keys. I could add pretty decent syntax for composition/proxying. I am trying very hard to end this section now.

The Lua philosophy

Lua’s philosophy is to… not have a philosophy? It gives you the bare minimum to make objects work, and you can do absolutely whatever you want from there. Lua does have something resembling prototypical inheritance, but it’s not so much a first-class feature as an emergent property of some very simple tools. And since you can make __index be a function, you could avoid the prototypical behavior and do something different entirely.

The very severe downside, of course, is that you have to find or build your own object system — which can get pretty confusing very quickly, what with the multiple small moving parts. Third-party code may also have its own object system with subtly different behavior. (Though, in my experience, third-party code tries very hard to avoid needing an object system at all.)

It’s hard to say what the Lua “culture” is like, since Lua is an embedded language that’s often a little different in each environment. I imagine it has a thousand millicultures, instead. I can say that the tedium of building my own object model has led me into something very “traditional”, with prototypical inheritance and whatnot. It’s partly what I’m used to, but it’s also just really dang easy to get working.

Likewise, while I love properties in Python and use them all the dang time, I’ve yet to use a single one in Lua. They wouldn’t be particularly hard to add to my object model, but having to add them myself (or shop around for an object model with them and also port all my code to use it) adds a huge amount of friction. I’ve thought about designing an interesting ECS with custom object behavior, too, but… is it really worth the effort? For all the power and flexibility Lua offers, the cost is that by the time I have something working at all, I’m too exhausted to actually use any of it.

JavaScript

JavaScript is notable for being preposterously heavily used, yet not having a class block.

Well. Okay. Yes. It has one now. It didn’t for a very long time, and even the one it has now is sugar.

Here’s a vector class again:

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class Vector {
    constructor(x, y) {
        this.x = x;
        this.y = y;
    }

    get magnitude() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    }

    dot(other) {
        return this.x * other.x + this.y * other.y;
    }
}

In “classic” JavaScript, this would be written as:

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function Vector(x, y) {
    this.x = x;
    this.y = y;
}

Object.defineProperty(Vector.prototype, 'magnitude', {
    configurable: true,
    enumerable: true,
    get: function() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    },
});


Vector.prototype.dot = function(other) {
    return this.x * other.x + this.y * other.y;
};

Hm, yes. I can see why they added class.

The JavaScript model

In JavaScript, a new type is defined in terms of a function, which is its constructor.

Right away we get into trouble here. There is a very big difference between these two invocations, which I actually completely forgot about just now after spending four hours writing about Python and Lua:

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let vec = Vector(3, 4);
let vec = new Vector(3, 4);

The first calls the function Vector. It assigns some properties to this, which here is going to be window, so now you have a global x and y. It then returns nothing, so vec is undefined.

The second calls Vector with this set to a new empty object, then evaluates to that object. The result is what you’d actually expect.

(You can detect this situation with the strange new.target expression, but I have never once remembered to do so.)

From here, we have true, honest-to-god, first-class prototypical inheritance. The word “prototype” is even right there. When you write this:

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vec.dot(vec2)

JavaScript will look for dot on vec and (presumably) not find it. It then consults vecs prototype, an object you can see for yourself by using Object.getPrototypeOf(). Since vec is a Vector, its prototype is Vector.prototype.

I stress that Vector.prototype is not the prototype for Vector. It’s the prototype for instances of Vector.

(I say “instance”, but the true type of vec here is still just object. If you want to find Vector, it’s automatically assigned to the constructor property of its own prototype, so it’s available as vec.constructor.)

Of course, Vector.prototype can itself have a prototype, in which case the process would continue if dot were not found. A common (and, arguably, very bad) way to simulate single inheritance is to set Class.prototype to an instance of a superclass to get the prototype right, then tack on the methods for Class. Nowadays we can do Object.create(Superclass.prototype).

Now that I’ve been through Python and Lua, though, this isn’t particularly surprising. I kinda spoiled it.

I suppose one difference in JavaScript is that you can tack arbitrary attributes directly onto Vector all you like, and they will remain invisible to instances since they aren’t in the prototype chain. This is kind of backwards from Lua, where you can squirrel stuff away in the metatable.

Another difference is that every single object in JavaScript has a bunch of properties already tacked on — the ones in Object.prototype. Every object (and by “object” I mean any mapping) has a prototype, and that prototype defaults to Object.prototype, and it has a bunch of ancient junk like isPrototypeOf.

(Nit: it’s possible to explicitly create an object with no prototype via Object.create(null).)

Like Lua, and unlike Python, JavaScript doesn’t distinguish between keys found on an object and keys found via a prototype. Properties can be defined on prototypes with Object.defineProperty(), but that works just as well directly on an object, too. JavaScript doesn’t have a lot of operator overloading, but some things like Symbol.iterator also work on both objects and prototypes.

About this

You may, at this point, be wondering what this is. Unlike Lua and Python (and the last language below), this is a special built-in value — a context value, invisibly passed for every function call.

It’s determined by where the function came from. If the function was the result of an attribute lookup, then this is set to the object containing that attribute. Otherwise, this is set to the global object, window. (You can also set this to whatever you want via the call method on functions.)

This decision is made lexically, i.e. from the literal source code as written. There are no Python-style bound methods. In other words:

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// this = obj
obj.method()
// this = window
let meth = obj.method
meth()

Also, because this is reassigned on every function call, it cannot be meaningfully closed over, which makes using closures within methods incredibly annoying. The old approach was to assign this to some other regular name like self (which got syntax highlighting since it’s also a built-in name in browsers); then we got Function.bind, which produced a callable thing with a fixed context value, which was kind of nice; and now finally we have arrow functions, which explicitly close over the current this when they’re defined and don’t change it when called. Phew.

Class syntax

I already showed class syntax, and it’s really just one big macro for doing all the prototype stuff The Right Way. It even prevents you from calling the type without new. The underlying model is exactly the same, and you can inspect all the parts.

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class Vector { ... }

console.log(Vector.prototype);  // { dot: ..., magnitude: ..., ... }
let vec = new Vector(3, 4);
console.log(Object.getPrototypeOf(vec));  // same as Vector.prototype

// i don't know why you would subclass vector but let's roll with it
class Vectest extends Vector { ... }

console.log(Vectest.prototype);  // { ... }
console.log(Object.getPrototypeOf(Vectest.prototype))  // same as Vector.prototype

Alas, class syntax has a couple shortcomings. You can’t use the class block to assign arbitrary data to either the type object or the prototype — apparently it was deemed too confusing that mutations would be shared among instances. Which… is… how prototypes work. How Python works. How JavaScript itself, one of the most popular languages of all time, has worked for twenty-two years. Argh.

You can still do whatever assignment you want outside of the class block, of course. It’s just a little ugly, and not something I’d think to look for with a sugary class.

A more subtle result of this behavior is that a class block isn’t quite the same syntax as an object literal. The check for data isn’t a runtime thing; class Foo { x: 3 } fails to parse. So JavaScript now has two largely but not entirely identical styles of key/value block.

Attribute access

Here’s where things start to come apart at the seams, just a little bit.

JavaScript doesn’t really have an attribute protocol. Instead, it has two… extension points, I suppose.

One is Object.defineProperty, seen above. For common cases, there’s also the get syntax inside a property literal, which does the same thing. But unlike Python’s @property, these aren’t wrappers around some simple primitives; they are the primitives. JavaScript is the only language of these four to have “property that runs code on access” as a completely separate first-class concept.

If you want to intercept arbitrary attribute access (and some kinds of operators), there’s a completely different primitive: the Proxy type. It doesn’t let you intercept attribute access or operators; instead, it produces a wrapper object that supports interception and defers to the wrapped object by default.

It’s cool to see composition used in this way, but also, extremely weird. If you want to make your own type that overloads in or calling, you have to return a Proxy that wraps your own type, rather than actually returning your own type. And (unlike the other three languages in this post) you can’t return a different type from a constructor, so you have to throw that away and produce objects only from a factory. And instanceof would be broken, but you can at least fix that with Symbol.hasInstance — which is really operator overloading, implement yet another completely different way.

I know the design here is a result of legacy and speed — if any object could intercept all attribute access, then all attribute access would be slowed down everywhere. Fair enough. It still leaves the surface area of the language a bit… bumpy?

The JavaScript philosophy

It’s a little hard to tell. The original idea of prototypes was interesting, but it was hidden behind some very awkward syntax. Since then, we’ve gotten a bunch of extra features awkwardly bolted on to reflect the wildly varied things the built-in types and DOM API were already doing. We have class syntax, but it’s been explicitly designed to avoid exposing the prototype parts of the model.

I admit I don’t do a lot of heavy JavaScript, so I might just be overlooking it, but I’ve seen virtually no code that makes use of any of the recent advances in object capabilities. Forget about custom iterators or overloading call; I can’t remember seeing any JavaScript in the wild that even uses properties yet. I don’t know if everyone’s waiting for sufficient browser support, nobody knows about them, or nobody cares.

The model has advanced recently, but I suspect JavaScript is still shackled to its legacy of “something about prototypes, I don’t really get it, just copy the other code that’s there” as an object model. Alas! Prototypes are so good. Hopefully class syntax will make it a bit more accessible, as it has in Python.

Perl 5

Perl 5 also doesn’t have an object system and expects you to build your own. But where Lua gives you two simple, powerful tools for building one, Perl 5 feels more like a puzzle with half the pieces missing. Clearly they were going for something, but they only gave you half of it.

In brief, a Perl object is a reference that has been blessed with a package.

I need to explain a few things. Honestly, one of the biggest problems with the original Perl object setup was how many strange corners and unique jargon you had to understand just to get off the ground.

(If you want to try running any of this code, you should stick a use v5.26; as the first line. Perl is very big on backwards compatibility, so you need to opt into breaking changes, and even the mundane say builtin is behind a feature gate.)

References

A reference in Perl is sort of like a pointer, but its main use is very different. See, Perl has the strange property that its data structures try very hard to spill their contents all over the place. Despite having dedicated syntax for arrays — @foo is an array variable, distinct from the single scalar variable $foo — it’s actually impossible to nest arrays.

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my @foo = (1, 2, 3, 4);
my @bar = (@foo, @foo);
# @bar is now a flat list of eight items: 1, 2, 3, 4, 1, 2, 3, 4

The idea, I guess, is that an array is not one thing. It’s not a container, which happens to hold multiple things; it is multiple things. Anywhere that expects a single value, such as an array element, cannot contain an array, because an array fundamentally is not a single value.

And so we have “references”, which are a form of indirection, but also have the nice property that they’re single values. They add containment around arrays, and in general they make working with most of Perl’s primitive types much more sensible. A reference to a variable can be taken with the \ operator, or you can use [ ... ] and { ... } to directly create references to anonymous arrays or hashes.

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my @foo = (1, 2, 3, 4);
my @bar = (\@foo, \@foo);
# @bar is now a nested list of two items: [1, 2, 3, 4], [1, 2, 3, 4]

(Incidentally, this is the sole reason I initially abandoned Perl for Python. Non-trivial software kinda requires nesting a lot of data structures, so you end up with references everywhere, and the syntax for going back and forth between a reference and its contents is tedious and ugly.)

A Perl object must be a reference. Perl doesn’t care what kind of reference — it’s usually a hash reference, since hashes are a convenient place to store arbitrary properties, but it could just as well be a reference to an array, a scalar, or even a sub (i.e. function) or filehandle.

I’m getting a little ahead of myself. First, the other half: blessing and packages.

Packages and blessing

Perl packages are just namespaces. A package looks like this:

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package Foo::Bar;

sub quux {
    say "hi from quux!";
}

# now Foo::Bar::quux() can be called from anywhere

Nothing shocking, right? It’s just a named container. A lot of the details are kind of weird, like how a package exists in some liminal quasi-value space, but the basic idea is a Bag Of Stuff.

The final piece is “blessing,” which is Perl’s funny name for binding a package to a reference. A very basic class might look like this:

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package Vector;

# the name 'new' is convention, not special
sub new {
    # perl argument passing is weird, don't ask
    my ($class, $x, $y) = @_;

    # create the object itself -- here, unusually, an array reference makes sense
    my $self = [ $x, $y ];

    # associate the package with that reference
    # note that $class here is just the regular string, 'Vector'
    bless $self, $class;

    return $self;
}

sub x {
    my ($self) = @_;
    return $self->[0];
}

sub y {
    my ($self) = @_;
    return $self->[1];
}

sub magnitude {
    my ($self) = @_;
    return sqrt($self->x ** 2 + $self->y ** 2);
}

# switch back to the "default" package
package main;

# -> is method call syntax, which passes the invocant as the first argument;
# for a package, that's just the package name
my $vec = Vector->new(3, 4);
say $vec->magnitude;  # 5

A few things of note here. First, $self->[0] has nothing to do with objects; it’s normal syntax for getting the value of a index 0 out of an array reference called $self. (Most classes are based on hashrefs and would use $self->{value} instead.) A blessed reference is still a reference and can be treated like one.

In general, -> is Perl’s dereferencey operator, but its exact behavior depends on what follows. If it’s followed by brackets, then it’ll apply the brackets to the thing in the reference: ->{} to index a hash reference, ->[] to index an array reference, and ->() to call a function reference.

But if -> is followed by an identifier, then it’s a method call. For packages, that means calling a function in the package and passing the package name as the first argument. For objects — blessed references — that means calling a function in the associated package and passing the object as the first argument.

This is a little weird! A blessed reference is a superposition of two things: its normal reference behavior, and some completely orthogonal object behavior. Also, object behavior has no notion of methods vs data; it only knows about methods. Perl lets you omit parentheses in a lot of places, including when calling a method with no arguments, so $vec->magnitude is really $vec->magnitude().

Perl’s blessing bears some similarities to Lua’s metatables, but ultimately Perl is much closer to Ruby’s “message passing” approach than the above three languages’ approaches of “get me something and maybe it’ll be callable”. (But this is no surprise — Ruby is a spiritual successor to Perl 5.)

All of this leads to one little wrinkle: how do you actually expose data? Above, I had to write x and y methods. Am I supposed to do that for every single attribute on my type?

Yes! But don’t worry, there are third-party modules to help with this incredibly fundamental task. Take Class::Accessor::Fast, so named because it’s faster than Class::Accessor:

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package Foo;
use base qw(Class::Accessor::Fast);
__PACKAGE__->mk_accessors(qw(fred wilma barney));

(__PACKAGE__ is the lexical name of the current package; qw(...) is a list literal that splits its contents on whitespace.)

This assumes you’re using a hashref with keys of the same names as the attributes. $obj->fred will return the fred key from your hashref, and $obj->fred(4) will change it to 4.

You also, somewhat bizarrely, have to inherit from Class::Accessor::Fast. Speaking of which,

Inheritance

Inheritance is done by populating the package-global @ISA array with some number of (string) names of parent packages. Most code instead opts to write use base ...;, which does the same thing. Or, more commonly, use parent ...;, which… also… does the same thing.

Every package implicitly inherits from UNIVERSAL, which can be freely modified by Perl code.

A method can call its superclass method with the SUPER:: pseudo-package:

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sub foo {
    my ($self) = @_;
    $self->SUPER::foo;
}

However, this does a depth-first search, which means it almost certainly does the wrong thing when faced with multiple inheritance. For a while the accepted solution involved a third-party module, but Perl eventually grew an alternative you have to opt into: C3, which may be more familiar to you as the order Python uses.

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use mro 'c3';

sub foo {
    my ($self) = @_;
    $self->next::method;
}

Offhand, I’m not actually sure how next::method works, seeing as it was originally implemented in pure Perl code. I suspect it involves peeking at the caller’s stack frame. If so, then this is a very different style of customizability from e.g. Python — the MRO was never intended to be pluggable, and the use of a special pseudo-package means it isn’t really, but someone was determined enough to make it happen anyway.

Operator overloading and whatnot

Operator overloading looks a little weird, though really it’s pretty standard Perl.

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package MyClass;

use overload '+' => \&_add;

sub _add {
    my ($self, $other, $swap) = @_;
    ...
}

use overload here is a pragma, where “pragma” means “regular-ass module that does some wizardry when imported”.

\&_add is how you get a reference to the _add sub so you can pass it to the overload module. If you just said &_add or _add, that would call it.

And that’s it; you just pass a map of operators to functions to this built-in module. No worry about name clashes or pollution, which is pretty nice. You don’t even have to give references to functions that live in the package, if you don’t want them to clog your namespace; you could put them in another package, or even inline them anonymously.

One especially interesting thing is that Perl lets you overload every operator. Perl has a lot of operators. It considers some math builtins like sqrt and trig functions to be operators, or at least operator-y enough that you can overload them. You can also overload the “file text” operators, such as -e $path to test whether a file exists. You can overload conversions, including implicit conversion to a regex. And most fascinating to me, you can overload dereferencing — that is, the thing Perl does when you say $hashref->{key} to get at the underlying hash. So a single object could pretend to be references of multiple different types, including a subref to implement callability. Neat.

Somewhat related: you can overload basic operators (indexing, etc.) on basic types (not references!) with the tie function, which is designed completely differently and looks for methods with fixed names. Go figure.

You can intercept calls to nonexistent methods by implementing a function called AUTOLOAD, within which the $AUTOLOAD global will contain the name of the method being called. Originally this feature was, I think, intended for loading binary components or large libraries on-the-fly only when needed, hence the name. Offhand I’m not sure I ever saw it used the way __getattr__ is used in Python.

Is there a way to intercept all method calls? I don’t think so, but it is Perl, so I must be forgetting something.

Actually no one does this any more

Like a decade ago, a council of elder sages sat down and put together a whole whizbang system that covers all of it: Moose.

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package Vector;
use Moose;

has x => (is => 'rw', isa => 'Int');
has y => (is => 'rw', isa => 'Int');

sub magnitude {
    my ($self) = @_;
    return sqrt($self->x ** 2 + $self->y ** 2);
}

Moose has its own way to do pretty much everything, and it’s all built on the same primitives. Moose also adds metaclasses, somehow, despite that the underlying model doesn’t actually support them? I’m not entirely sure how they managed that, but I do remember doing some class introspection with Moose and it was much nicer than the built-in way.

(If you’re wondering, the built-in way begins with looking at the hash called %Vector::. No, that’s not a typo.)

I really cannot stress enough just how much stuff Moose does, but I don’t want to delve into it here since Moose itself is not actually the language model.

The Perl philosophy

I hope you can see what I meant with what I first said about Perl, now. It has multiple inheritance with an MRO, but uses the wrong one by default. It has extensive operator overloading, which looks nothing like how inheritance works, and also some of it uses a totally different mechanism with special method names instead. It only understands methods, not data, leaving you to figure out accessors by hand.

There’s 70% of an object system here with a clear general design it was gunning for, but none of the pieces really look anything like each other. It’s weird, in a distinctly Perl way.

The result is certainly flexible, at least! It’s especially cool that you can use whatever kind of reference you want for storage, though even as I say that, I acknowledge it’s no different from simply subclassing list or something in Python. It feels different in Perl, but maybe only because it looks so different.

I haven’t written much Perl in a long time, so I don’t know what the community is like any more. Moose was already ubiquitous when I left, which you’d think would let me say “the community mostly focuses on the stuff Moose can do” — but even a decade ago, Moose could already do far more than I had ever seen done by hand in Perl. It’s always made a big deal out of roles (read: interfaces), for instance, despite that I’d never seen anyone care about them in Perl before Moose came along. Maybe their presence in Moose has made them more popular? Who knows.

Also, I wrote Perl seriously, but in the intervening years I’ve only encountered people who only ever used Perl for one-offs. Maybe it’ll come as a surprise to a lot of readers that Perl has an object model at all.

End

Well, that was fun! I hope any of that made sense.

Special mention goes to Rust, which doesn’t have an object model you can fiddle with at runtime, but does do things a little differently.

It’s been really interesting thinking about how tiny differences make a huge impact on what people do in practice. Take the choice of storage in Perl versus Python. Perl’s massively common URI class uses a string as the storage, nothing else; I haven’t seen anything like that in Python aside from markupsafe, which is specifically designed as a string type. I would guess this is partly because Perl makes you choose — using a hashref is an obvious default, but you have to make that choice one way or the other. In Python (especially 3), inheriting from object and getting dict-based storage is the obvious thing to do; the ability to use another type isn’t quite so obvious, and doing it “right” involves a tiny bit of extra work.

Or, consider that Lua could have descriptors, but the extra bit of work (especially design work) has been enough of an impediment that I’ve never implemented them. I don’t think the object implementations I’ve looked at have included them, either. Super weird!

In that light, it’s only natural that objects would be so strongly associated with the features Java and C++ attach to them. I think that makes it all the more important to play around! Look at what Moose has done. No, really, you should bear in mind my description of how Perl does stuff and flip through the Moose documentation. It’s amazing what they’ve built.