Tag Archives: mana

digiKam 5.6.0 is released

Post Syndicated from ris original https://lwn.net/Articles/726278/rss

The digiKam Team has released
version 5.6.0 of the digiKam Software Collection for photo management. “With this version the HTML gallery and the video slideshow tools are back, database shrinking (e.g. purging stale thumbnails) is also supported on MySQL, grouping items feature has been improved, the support for custom sidecars type-mime have been added, the geolocation bookmarks introduce fixes to be fully functional with bundles, the support for custom sidecars, and of course a lots of bug has been fixed.

How to Create an AMI Builder with AWS CodeBuild and HashiCorp Packer – Part 2

Post Syndicated from Heitor Lessa original https://aws.amazon.com/blogs/devops/how-to-create-an-ami-builder-with-aws-codebuild-and-hashicorp-packer-part-2/

Written by AWS Solutions Architects Jason Barto and Heitor Lessa

 
In Part 1 of this post, we described how AWS CodeBuild, AWS CodeCommit, and HashiCorp Packer can be used to build an Amazon Machine Image (AMI) from the latest version of Amazon Linux. In this post, we show how to use AWS CodePipeline, AWS CloudFormation, and Amazon CloudWatch Events to continuously ship new AMIs. We use Ansible by Red Hat to harden the OS on the AMIs through a well-known set of security controls outlined by the Center for Internet Security in its CIS Amazon Linux Benchmark.

You’ll find the source code for this post in our GitHub repo.

At the end of this post, we will have the following architecture:

Requirements

 
To follow along, you will need Git and a text editor. Make sure Git is configured to work with AWS CodeCommit, as described in Part 1.

Technologies

 
In addition to the services and products used in Part 1 of this post, we also use these AWS services and third-party software:

AWS CloudFormation gives developers and systems administrators an easy way to create and manage a collection of related AWS resources, provisioning and updating them in an orderly and predictable fashion.

Amazon CloudWatch Events enables you to react selectively to events in the cloud and in your applications. Specifically, you can create CloudWatch Events rules that match event patterns, and take actions in response to those patterns.

AWS CodePipeline is a continuous integration and continuous delivery service for fast and reliable application and infrastructure updates. AWS CodePipeline builds, tests, and deploys your code every time there is a code change, based on release process models you define.

Amazon SNS is a fast, flexible, fully managed push notification service that lets you send individual messages or to fan out messages to large numbers of recipients. Amazon SNS makes it simple and cost-effective to send push notifications to mobile device users or email recipients. The service can even send messages to other distributed services.

Ansible is a simple IT automation system that handles configuration management, application deployment, cloud provisioning, ad-hoc task-execution, and multinode orchestration.

Getting Started

 
We use CloudFormation to bootstrap the following infrastructure:

Component Purpose
AWS CodeCommit repository Git repository where the AMI builder code is stored.
S3 bucket Build artifact repository used by AWS CodePipeline and AWS CodeBuild.
AWS CodeBuild project Executes the AWS CodeBuild instructions contained in the build specification file.
AWS CodePipeline pipeline Orchestrates the AMI build process, triggered by new changes in the AWS CodeCommit repository.
SNS topic Notifies subscribed email addresses when an AMI build is complete.
CloudWatch Events rule Defines how the AMI builder should send a custom event to notify an SNS topic.
Region AMI Builder Launch Template
N. Virginia (us-east-1)
Ireland (eu-west-1)

After launching the CloudFormation template linked here, we will have a pipeline in the AWS CodePipeline console. (Failed at this stage simply means we don’t have any data in our newly created AWS CodeCommit Git repository.)

Next, we will clone the newly created AWS CodeCommit repository.

If this is your first time connecting to a AWS CodeCommit repository, please see instructions in our documentation on Setup steps for HTTPS Connections to AWS CodeCommit Repositories.

To clone the AWS CodeCommit repository (console)

  1. From the AWS Management Console, open the AWS CloudFormation console.
  2. Choose the AMI-Builder-Blogpost stack, and then choose Output.
  3. Make a note of the Git repository URL.
  4. Use git to clone the repository.

For example: git clone https://git-codecommit.eu-west-1.amazonaws.com/v1/repos/AMI-Builder_repo

To clone the AWS CodeCommit repository (CLI)

# Retrieve CodeCommit repo URL
git_repo=$(aws cloudformation describe-stacks --query 'Stacks[0].Outputs[?OutputKey==`GitRepository`].OutputValue' --output text --stack-name "AMI-Builder-Blogpost")

# Clone repository locally
git clone ${git_repo}

Bootstrap the Repo with the AMI Builder Structure

 
Now that our infrastructure is ready, download all the files and templates required to build the AMI.

Your local Git repo should have the following structure:

.
├── ami_builder_event.json
├── ansible
├── buildspec.yml
├── cloudformation
├── packer_cis.json

Next, push these changes to AWS CodeCommit, and then let AWS CodePipeline orchestrate the creation of the AMI:

git add .
git commit -m "My first AMI"
git push origin master

AWS CodeBuild Implementation Details

 
While we wait for the AMI to be created, let’s see what’s changed in our AWS CodeBuild buildspec.yml file:

...
phases:
  ...
  build:
    commands:
      ...
      - ./packer build -color=false packer_cis.json | tee build.log
  post_build:
    commands:
      - egrep "${AWS_REGION}\:\sami\-" build.log | cut -d' ' -f2 > ami_id.txt
      # Packer doesn't return non-zero status; we must do that if Packer build failed
      - test -s ami_id.txt || exit 1
      - sed -i.bak "s/<<AMI-ID>>/$(cat ami_id.txt)/g" ami_builder_event.json
      - aws events put-events --entries file://ami_builder_event.json
      ...
artifacts:
  files:
    - ami_builder_event.json
    - build.log
  discard-paths: yes

In the build phase, we capture Packer output into a file named build.log. In the post_build phase, we take the following actions:

  1. Look up the AMI ID created by Packer and save its findings to a temporary file (ami_id.txt).
  2. Forcefully make AWS CodeBuild to fail if the AMI ID (ami_id.txt) is not found. This is required because Packer doesn’t fail if something goes wrong during the AMI creation process. We have to tell AWS CodeBuild to stop by informing it that an error occurred.
  3. If an AMI ID is found, we update the ami_builder_event.json file and then notify CloudWatch Events that the AMI creation process is complete.
  4. CloudWatch Events publishes a message to an SNS topic. Anyone subscribed to the topic will be notified in email that an AMI has been created.

Lastly, the new artifacts phase instructs AWS CodeBuild to upload files built during the build process (ami_builder_event.json and build.log) to the S3 bucket specified in the Outputs section of the CloudFormation template. These artifacts can then be used as an input artifact in any later stage in AWS CodePipeline.

For information about customizing the artifacts sequence of the buildspec.yml, see the Build Specification Reference for AWS CodeBuild.

CloudWatch Events Implementation Details

 
CloudWatch Events allow you to extend the AMI builder to not only send email after the AMI has been created, but to hook up any of the supported targets to react to the AMI builder event. This event publication means you can decouple from Packer actions you might take after AMI completion and plug in other actions, as you see fit.

For more information about targets in CloudWatch Events, see the CloudWatch Events API Reference.

In this case, CloudWatch Events should receive the following event, match it with a rule we created through CloudFormation, and publish a message to SNS so that you can receive an email.

Example CloudWatch custom event

[
        {
            "Source": "com.ami.builder",
            "DetailType": "AmiBuilder",
            "Detail": "{ \"AmiStatus\": \"Created\"}",
            "Resources": [ "ami-12cd5guf" ]
        }
]

Cloudwatch Events rule

{
  "detail-type": [
    "AmiBuilder"
  ],
  "source": [
    "com.ami.builder"
  ],
  "detail": {
    "AmiStatus": [
      "Created"
    ]
  }
}

Example SNS message sent in email

{
    "version": "0",
    "id": "f8bdede0-b9d7...",
    "detail-type": "AmiBuilder",
    "source": "com.ami.builder",
    "account": "<<aws_account_number>>",
    "time": "2017-04-28T17:56:40Z",
    "region": "eu-west-1",
    "resources": ["ami-112cd5guf "],
    "detail": {
        "AmiStatus": "Created"
    }
}

Packer Implementation Details

 
In addition to the build specification file, there are differences between the current version of the HashiCorp Packer template (packer_cis.json) and the one used in Part 1.

Variables

  "variables": {
    "vpc": "{{env `BUILD_VPC_ID`}}",
    "subnet": "{{env `BUILD_SUBNET_ID`}}",
         “ami_name”: “Prod-CIS-Latest-AMZN-{{isotime \”02-Jan-06 03_04_05\”}}”
  },
  • ami_name: Prefixes a name used by Packer to tag resources during the Builders sequence.
  • vpc and subnet: Environment variables defined by the CloudFormation stack parameters.

We no longer assume a default VPC is present and instead use the VPC and subnet specified in the CloudFormation parameters. CloudFormation configures the AWS CodeBuild project to use these values as environment variables. They are made available throughout the build process.

That allows for more flexibility should you need to change which VPC and subnet will be used by Packer to launch temporary resources.

Builders

  "builders": [{
    ...
    "ami_name": “{{user `ami_name`| clean_ami_name}}”,
    "tags": {
      "Name": “{{user `ami_name`}}”,
    },
    "run_tags": {
      "Name": “{{user `ami_name`}}",
    },
    "run_volume_tags": {
      "Name": “{{user `ami_name`}}",
    },
    "snapshot_tags": {
      "Name": “{{user `ami_name`}}",
    },
    ...
    "vpc_id": "{{user `vpc` }}",
    "subnet_id": "{{user `subnet` }}"
  }],

We now have new properties (*_tag) and a new function (clean_ami_name) and launch temporary resources in a VPC and subnet specified in the environment variables. AMI names can only contain a certain set of ASCII characters. If the input in project deviates from the expected characters (for example, includes whitespace or slashes), Packer’s clean_ami_name function will fix it.

For more information, see functions on the HashiCorp Packer website.

Provisioners

  "provisioners": [
    {
        "type": "shell",
        "inline": [
            "sudo pip install ansible"
        ]
    }, 
    {
        "type": "ansible-local",
        "playbook_file": "ansible/playbook.yaml",
        "role_paths": [
            "ansible/roles/common"
        ],
        "playbook_dir": "ansible",
        "galaxy_file": "ansible/requirements.yaml"
    },
    {
      "type": "shell",
      "inline": [
        "rm .ssh/authorized_keys ; sudo rm /root/.ssh/authorized_keys"
      ]
    }

We used shell provisioner to apply OS patches in Part 1. Now, we use shell to install Ansible on the target machine and ansible-local to import, install, and execute Ansible roles to make our target machine conform to our standards.

Packer uses shell to remove temporary keys before it creates an AMI from the target and temporary EC2 instance.

Ansible Implementation Details

 
Ansible provides OS patching through a custom Common role that can be easily customized for other tasks.

CIS Benchmark and Cloudwatch Logs are implemented through two Ansible third-party roles that are defined in ansible/requirements.yaml as seen in the Packer template.

The Ansible provisioner uses Ansible Galaxy to download these roles onto the target machine and execute them as instructed by ansible/playbook.yaml.

For information about how these components are organized, see the Playbook Roles and Include Statements in the Ansible documentation.

The following Ansible playbook (ansible</playbook.yaml) controls the execution order and custom properties:

---
- hosts: localhost
  connection: local
  gather_facts: true    # gather OS info that is made available for tasks/roles
  become: yes           # majority of CIS tasks require root
  vars:
    # CIS Controls whitepaper:  http://bit.ly/2mGAmUc
    # AWS CIS Whitepaper:       http://bit.ly/2m2Ovrh
    cis_level_1_exclusions:
    # 3.4.2 and 3.4.3 effectively blocks access to all ports to the machine
    ## This can break automation; ignoring it as there are stronger mechanisms than that
      - 3.4.2 
      - 3.4.3
    # CloudWatch Logs will be used instead of Rsyslog/Syslog-ng
    ## Same would be true if any other software doesn't support Rsyslog/Syslog-ng mechanisms
      - 4.2.1.4
      - 4.2.2.4
      - 4.2.2.5
    # Autofs is not installed in newer versions, let's ignore
      - 1.1.19
    # Cloudwatch Logs role configuration
    logs:
      - file: /var/log/messages
        group_name: "system_logs"
  roles:
    - common
    - anthcourtney.cis-amazon-linux
    - dharrisio.aws-cloudwatch-logs-agent

Both third-party Ansible roles can be easily configured through variables (vars). We use Ansible playbook variables to exclude CIS controls that don’t apply to our case and to instruct the CloudWatch Logs agent to stream the /var/log/messages log file to CloudWatch Logs.

If you need to add more OS or application logs, you can easily duplicate the playbook and make changes. The CloudWatch Logs agent will ship configured log messages to CloudWatch Logs.

For more information about parameters you can use to further customize third-party roles, download Ansible roles for the Cloudwatch Logs Agent and CIS Amazon Linux from the Galaxy website.

Committing Changes

 
Now that Ansible and CloudWatch Events are configured as a part of the build process, commiting any changes to the AWS CodeComit Git Repository will triger a new AMI build process that can be followed through the AWS CodePipeline console.

When the build is complete, an email will be sent to the email address you provided as a part of the CloudFormation stack deployment. The email serves as notification that an AMI has been built and is ready for use.

Summary

 
We used AWS CodeCommit, AWS CodePipeline, AWS CodeBuild, Packer, and Ansible to build a pipeline that continuously builds new, hardened CIS AMIs. We used Amazon SNS so that email addresses subscribed to a SNS topic are notified upon completion of the AMI build.

By treating our AMI creation process as code, we can iterate and track changes over time. In this way, it’s no different from a software development workflow. With that in mind, software patches, OS configuration, and logs that need to be shipped to a central location are only a git commit away.

Next Steps

 
Here are some ideas to extend this AMI builder:

  • Hook up a Lambda function in Cloudwatch Events to update EC2 Auto Scaling configuration upon completion of the AMI build.
  • Use AWS CodePipeline parallel steps to build multiple Packer images.
  • Add a commit ID as a tag for the AMI you created.
  • Create a scheduled Lambda function through Cloudwatch Events to clean up old AMIs based on timestamp (name or additional tag).
  • Implement Windows support for the AMI builder.
  • Create a cross-account or cross-region AMI build.

Cloudwatch Events allow the AMI builder to decouple AMI configuration and creation so that you can easily add your own logic using targets (AWS Lambda, Amazon SQS, Amazon SNS) to add events or recycle EC2 instances with the new AMI.

If you have questions or other feedback, feel free to leave it in the comments or contribute to the AMI Builder repo on GitHub.

DynamoDB Accelerator (DAX) Now Generally Available

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/dynamodb-accelerator-dax-now-generally-available/

Earlier this year I told you about Amazon DynamoDB Accelerator (DAX), a fully-managed caching service that sits in front of (logically speaking) your Amazon DynamoDB tables. DAX returns cached responses in microseconds, making it a great fit for eventually-consistent read-intensive workloads. DAX supports the DynamoDB API, and is seamless and easy to use. As a managed service, you simply create your DAX cluster and use it as the target for your existing reads and writes. You don’t have to worry about patching, cluster maintenance, replication, or fault management.

Now Generally Available
Today I am pleased to announce that DAX is now generally available. We have expanded DAX into additional AWS Regions and used the preview time to fine-tune performance and availability:

Now in Five Regions – DAX is now available in the US East (Northern Virginia), EU (Ireland), US West (Oregon), Asia Pacific (Tokyo), and US West (Northern California) Regions.

In Production – Our preview customers are reporting that they are using DAX in production, that they loved how easy it was to add DAX to their application, and have told us that their apps are now running 10x faster.

Getting Started with DAX
As I outlined in my earlier post, it is easy to use DAX to accelerate your existing DynamoDB applications. You simply create a DAX cluster in the desired region, update your application to reference the DAX SDK for Java (the calls are the same; this is a drop-in replacement), and configure the SDK to use the endpoint to your cluster. As a read-through/write-through cache, DAX seamlessly handles all of the DynamoDB read/write APIs.

We are working on SDK support for other languages, and I will share additional information as it becomes available.

DAX Pricing
You pay for each node in the cluster (see the DynamoDB Pricing page for more information) on a per-hour basis, with prices starting at $0.269 per hour in the US East (Northern Virginia) and US West (Oregon) regions. With DAX, each of the nodes in your cluster serves as a read target and as a failover target for high availability. The DAX SDK is cluster aware and will issue round-robin requests to all nodes in the cluster so that you get to make full use of the cluster’s cache resources.

Because DAX can easily handle sudden spikes in read traffic, you may be able to reduce the amount of provisioned throughput for your tables, resulting in an overall cost savings while still returning results in microseconds.

Jeff;

 

Raffeiner: My Ubuntu for mobile devices post mortem analysis

Post Syndicated from corbet original https://lwn.net/Articles/726034/rss

Simon Raffeiner describes
in detail
the reasons he sees for the failure of the Ubuntu phone
project.
I understand there weren’t enough developers to fix everything at
once, but instead of deciding to either make a good phone OR a good tablet
with Convergence, we had devices which couldn’t really do anything
right. The whole project also always always had this ‘these are developer
devices, it’s not important to do it fast, we will win in the long run’ air
around it – until the management quite obviously realised that this was all
way too expensive and too much time had already been lost.

Building Loosely Coupled, Scalable, C# Applications with Amazon SQS and Amazon SNS

Post Syndicated from Tara Van Unen original https://aws.amazon.com/blogs/compute/building-loosely-coupled-scalable-c-applications-with-amazon-sqs-and-amazon-sns/

 
Stephen Liedig, Solutions Architect

 

One of the many challenges professional software architects and developers face is how to make cloud-native applications scalable, fault-tolerant, and highly available.

Fundamental to your project success is understanding the importance of making systems highly cohesive and loosely coupled. That means considering the multi-dimensional facets of system coupling to support the distributed nature of the applications that you are building for the cloud.

By that, I mean addressing not only the application-level coupling (managing incoming and outgoing dependencies), but also considering the impacts of of platform, spatial, and temporal coupling of your systems. Platform coupling relates to the interoperability, or lack thereof, of heterogeneous systems components. Spatial coupling deals with managing components at a network topology level or protocol level. Temporal, or runtime coupling, refers to the ability of a component within your system to do any kind of meaningful work while it is performing a synchronous, blocking operation.

The AWS messaging services, Amazon SQS and Amazon SNS, help you deal with these forms of coupling by providing mechanisms for:

  • Reliable, durable, and fault-tolerant delivery of messages between application components
  • Logical decomposition of systems and increased autonomy of components
  • Creating unidirectional, non-blocking operations, temporarily decoupling system components at runtime
  • Decreasing the dependencies that components have on each other through standard communication and network channels

Following on the recent topic, Building Scalable Applications and Microservices: Adding Messaging to Your Toolbox, in this post, I look at some of the ways you can introduce SQS and SNS into your architectures to decouple your components, and show how you can implement them using C#.

Walkthrough

To illustrate some of these concepts, consider a web application that processes customer orders. As good architects and developers, you have followed best practices and made your application scalable and highly available. Your solution included implementing load balancing, dynamic scaling across multiple Availability Zones, and persisting orders in a Multi-AZ Amazon RDS database instance, as in the following diagram.


In this example, the application is responsible for handling and persisting the order data, as well as dealing with increases in traffic for popular items.

One potential point of vulnerability in the order processing workflow is in saving the order in the database. The business expects that every order has been persisted into the database. However, any potential deadlock, race condition, or network issue could cause the persistence of the order to fail. Then, the order is lost with no recourse to restore the order.

With good logging capability, you may be able to identify when an error occurred and which customer’s order failed. This wouldn’t allow you to “restore” the transaction, and by that stage, your customer is no longer your customer.

As illustrated in the following diagram, introducing an SQS queue helps improve your ordering application. Using the queue isolates the processing logic into its own component and runs it in a separate process from the web application. This, in turn, allows the system to be more resilient to spikes in traffic, while allowing work to be performed only as fast as necessary in order to manage costs.


In addition, you now have a mechanism for persisting orders as messages (with the queue acting as a temporary database), and have moved the scope of your transaction with your database further down the stack. In the event of an application exception or transaction failure, this ensures that the order processing can be retired or redirected to the Amazon SQS Dead Letter Queue (DLQ), for re-processing at a later stage. (See the recent post, Using Amazon SQS Dead-Letter Queues to Control Message Failure, for more information on dead-letter queues.)

Scaling the order processing nodes

This change allows you now to scale the web application frontend independently from the processing nodes. The frontend application can continue to scale based on metrics such as CPU usage, or the number of requests hitting the load balancer. Processing nodes can scale based on the number of orders in the queue. Here is an example of scale-in and scale-out alarms that you would associate with the scaling policy.

Scale-out Alarm

aws cloudwatch put-metric-alarm --alarm-name AddCapacityToCustomerOrderQueue --metric-name ApproximateNumberOfMessagesVisible --namespace "AWS/SQS" 
--statistic Average --period 300 --threshold 3 --comparison-operator GreaterThanOrEqualToThreshold --dimensions Name=QueueName,Value=customer-orders
--evaluation-periods 2 --alarm-actions <arn of the scale-out autoscaling policy>

Scale-in Alarm

aws cloudwatch put-metric-alarm --alarm-name RemoveCapacityFromCustomerOrderQueue --metric-name ApproximateNumberOfMessagesVisible --namespace "AWS/SQS" 
 --statistic Average --period 300 --threshold 1 --comparison-operator LessThanOrEqualToThreshold --dimensions Name=QueueName,Value=customer-orders
 --evaluation-periods 2 --alarm-actions <arn of the scale-in autoscaling policy>

In the above example, use the ApproximateNumberOfMessagesVisible metric to discover the queue length and drive the scaling policy of the Auto Scaling group. Another useful metric is ApproximateAgeOfOldestMessage, when applications have time-sensitive messages and developers need to ensure that messages are processed within a specific time period.

Scaling the order processing implementation

On top of scaling at an infrastructure level using Auto Scaling, make sure to take advantage of the processing power of your Amazon EC2 instances by using as many of the available threads as possible. There are several ways to implement this. In this post, we build a Windows service that uses the BackgroundWorker class to process the messages from the queue.

Here’s a closer look at the implementation. In the first section of the consuming application, use a loop to continually poll the queue for new messages, and construct a ReceiveMessageRequest variable.

public static void PollQueue()
{
    while (_running)
    {
        Task<ReceiveMessageResponse> receiveMessageResponse;

        // Pull messages off the queue
        using (var sqs = new AmazonSQSClient())
        {
            const int maxMessages = 10;  // 1-10

            //Receiving a message
            var receiveMessageRequest = new ReceiveMessageRequest
            {
                // Get URL from Configuration
                QueueUrl = _queueUrl, 
                // The maximum number of messages to return. 
                // Fewer messages might be returned. 
                MaxNumberOfMessages = maxMessages, 
                // A list of attributes that need to be returned with message.
                AttributeNames = new List<string> { "All" },
                // Enable long polling. 
                // Time to wait for message to arrive on queue.
                WaitTimeSeconds = 5 
            };

            receiveMessageResponse = sqs.ReceiveMessageAsync(receiveMessageRequest);
        }

The WaitTimeSeconds property of the ReceiveMessageRequest specifies the duration (in seconds) that the call waits for a message to arrive in the queue before returning a response to the calling application. There are a few benefits to using long polling:

  • It reduces the number of empty responses by allowing SQS to wait until a message is available in the queue before sending a response.
  • It eliminates false empty responses by querying all (rather than a limited number) of the servers.
  • It returns messages as soon any message becomes available.

For more information, see Amazon SQS Long Polling.

After you have returned messages from the queue, you can start to process them by looping through each message in the response and invoking a new BackgroundWorker thread.

// Process messages
if (receiveMessageResponse.Result.Messages != null)
{
    foreach (var message in receiveMessageResponse.Result.Messages)
    {
        Console.WriteLine("Received SQS message, starting worker thread");

        // Create background worker to process message
        BackgroundWorker worker = new BackgroundWorker();
        worker.DoWork += (obj, e) => ProcessMessage(message);
        worker.RunWorkerAsync();
    }
}
else
{
    Console.WriteLine("No messages on queue");
}

The event handler, ProcessMessage, is where you implement business logic for processing orders. It is important to have a good understanding of how long a typical transaction takes so you can set a message VisibilityTimeout that is long enough to complete your operation. If order processing takes longer than the specified timeout period, the message becomes visible on the queue. Other nodes may pick it and process the same order twice, leading to unintended consequences.

Handling Duplicate Messages

In order to manage duplicate messages, seek to make your processing application idempotent. In mathematics, idempotent describes a function that produces the same result if it is applied to itself:

f(x) = f(f(x))

No matter how many times you process the same message, the end result is the same (definition from Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions, Hohpe and Wolf, 2004).

There are several strategies you could apply to achieve this:

  • Create messages that have inherent idempotent characteristics. That is, they are non-transactional in nature and are unique at a specified point in time. Rather than saying “place new order for Customer A,” which adds a duplicate order to the customer, use “place order <orderid> on <timestamp> for Customer A,” which creates a single order no matter how often it is persisted.
  • Deliver your messages via an Amazon SQS FIFO queue, which provides the benefits of message sequencing, but also mechanisms for content-based deduplication. You can deduplicate using the MessageDeduplicationId property on the SendMessage request or by enabling content-based deduplication on the queue, which generates a hash for MessageDeduplicationId, based on the content of the message, not the attributes.
var sendMessageRequest = new SendMessageRequest
{
    QueueUrl = _queueUrl,
    MessageBody = JsonConvert.SerializeObject(order),
    MessageGroupId = Guid.NewGuid().ToString("N"),
    MessageDeduplicationId = Guid.NewGuid().ToString("N")
};
  • If using SQS FIFO queues is not an option, keep a message log of all messages attributes processed for a specified period of time, as an alternative to message deduplication on the receiving end. Verifying the existence of the message in the log before processing the message adds additional computational overhead to your processing. This can be minimized through low latency persistence solutions such as Amazon DynamoDB. Bear in mind that this solution is dependent on the successful, distributed transaction of the message and the message log.

Handling exceptions

Because of the distributed nature of SQS queues, it does not automatically delete the message. Therefore, you must explicitly delete the message from the queue after processing it, using the message ReceiptHandle property (see the following code example).

However, if at any stage you have an exception, avoid handling it as you normally would. The intention is to make sure that the message ends back on the queue, so that you can gracefully deal with intermittent failures. Instead, log the exception to capture diagnostic information, and swallow it.

By not explicitly deleting the message from the queue, you can take advantage of the VisibilityTimeout behavior described earlier. Gracefully handle the message processing failure and make the unprocessed message available to other nodes to process.

In the event that subsequent retries fail, SQS automatically moves the message to the configured DLQ after the configured number of receives has been reached. You can further investigate why the order process failed. Most importantly, the order has not been lost, and your customer is still your customer.

private static void ProcessMessage(Message message)
{
    using (var sqs = new AmazonSQSClient())
    {
        try
        {
            Console.WriteLine("Processing message id: {0}", message.MessageId);

            // Implement messaging processing here
            // Ensure no downstream resource contention (parallel processing)
            // <your order processing logic in here…>
            Console.WriteLine("{0} Thread {1}: {2}", DateTime.Now.ToString("s"), Thread.CurrentThread.ManagedThreadId, message.MessageId);
            
            // Delete the message off the queue. 
            // Receipt handle is the identifier you must provide 
            // when deleting the message.
            var deleteRequest = new DeleteMessageRequest(_queueName, message.ReceiptHandle);
            sqs.DeleteMessageAsync(deleteRequest);
            Console.WriteLine("Processed message id: {0}", message.MessageId);

        }
        catch (Exception ex)
        {
            // Do nothing.
            // Swallow exception, message will return to the queue when 
            // visibility timeout has been exceeded.
            Console.WriteLine("Could not process message due to error. Exception: {0}", ex.Message);
        }
    }
}

Using SQS to adapt to changing business requirements

One of the benefits of introducing a message queue is that you can accommodate new business requirements without dramatically affecting your application.

If, for example, the business decided that all orders placed over $5000 are to be handled as a priority, you could introduce a new “priority order” queue. The way the orders are processed does not change. The only significant change to the processing application is to ensure that messages from the “priority order” queue are processed before the “standard order” queue.

The following diagram shows how this logic could be isolated in an “order dispatcher,” whose only purpose is to route order messages to the appropriate queue based on whether the order exceeds $5000. Nothing on the web application or the processing nodes changes other than the target queue to which the order is sent. The rates at which orders are processed can be achieved by modifying the poll rates and scalability settings that I have already discussed.

Extending the design pattern with Amazon SNS

Amazon SNS supports reliable publish-subscribe (pub-sub) scenarios and push notifications to known endpoints across a wide variety of protocols. It eliminates the need to periodically check or poll for new information and updates. SNS supports:

  • Reliable storage of messages for immediate or delayed processing
  • Publish / subscribe – direct, broadcast, targeted “push” messaging
  • Multiple subscriber protocols
  • Amazon SQS, HTTP, HTTPS, email, SMS, mobile push, AWS Lambda

With these capabilities, you can provide parallel asynchronous processing of orders in the system and extend it to support any number of different business use cases without affecting the production environment. This is commonly referred to as a “fanout” scenario.

Rather than your web application pushing orders to a queue for processing, send a notification via SNS. The SNS messages are sent to a topic and then replicated and pushed to multiple SQS queues and Lambda functions for processing.

As the diagram above shows, you have the development team consuming “live” data as they work on the next version of the processing application, or potentially using the messages to troubleshoot issues in production.

Marketing is consuming all order information, via a Lambda function that has subscribed to the SNS topic, inserting the records into an Amazon Redshift warehouse for analysis.

All of this, of course, is happening without affecting your order processing application.

Summary

While I haven’t dived deep into the specifics of each service, I have discussed how these services can be applied at an architectural level to build loosely coupled systems that facilitate multiple business use cases. I’ve also shown you how to use infrastructure and application-level scaling techniques, so you can get the most out of your EC2 instances.

One of the many benefits of using these managed services is how quickly and easily you can implement powerful messaging capabilities in your systems, and lower the capital and operational costs of managing your own messaging middleware.

Using Amazon SQS and Amazon SNS together can provide you with a powerful mechanism for decoupling application components. This should be part of design considerations as you architect for the cloud.

For more information, see the Amazon SQS Developer Guide and Amazon SNS Developer Guide. You’ll find tutorials on all the concepts covered in this post, and more. To can get started using the AWS console or SDK of your choice visit:

Happy messaging!

Schaller: Fedora Workstation 26 and beyond

Post Syndicated from corbet original https://lwn.net/Articles/725992/rss

Christian Schaller has posted an
extensive look forward
at the changes coming to the Fedora desktop.
Another major project we been working on for a long time in Fleet
Commander. Fleet Commander is a tool to allow you to manage Fedora and RHEL
desktops centrally. This is a tool targeted at for instance Universities or
companies with tens, hundreds or thousands of workstation installation. It
gives you a graphical browser based UI (accessible through Cockpit) to
create configuration profiles and deploy across your organization.

Shelfchecker Smart Shelf: build a home library system

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/smart-shelf-home-library/

Are you tired of friends borrowing your books and never returning them? Maybe you’re sure you own 1984 but can’t seem to locate it? Do you find a strange satisfaction in using the supermarket self-checkout simply because of the barcode beep? With the ShelfChecker smart shelf from maker Annelynn described on Instructables, you can be your own librarian and never misplace your books again! Beep!

Shelfchecker smart shelf annelynn Raspberry Pi

Harry Potter and the Aesthetically Pleasing Smart Shelf

The ShelfChecker smart shelf

Annelynn built her smart shelf utilising a barcode scanner, LDR light sensors, a Raspberry Pi, plus a few other peripherals and some Python scripts. She has created a fully integrated library checkout system with accompanying NeoPixel location notification for your favourite books.

This build allows you to issue your book-borrowing friends their own IDs and catalogue their usage of your treasured library. On top of that, you’ll be able to use LED NeoPixels to highlight your favourite books, registering their removal and return via light sensor tracking.

Using light sensors for book cataloguing

Once Annelynn had built the shelf, she drilled holes to fit the eight LDRs that would guard her favourite books, and separated them with corner brackets to prevent confusion.

Shelfchecker smart shelf annelynn Raspberry Pi

Corner brackets keep the books in place without confusion between their respective light sensors

Due to the limitations of the MCP3008 Adafruit microchip, the smart shelf can only keep track of eight of your favourite books. But this limitation won’t stop you from cataloguing your entire home library; it simply means you get to pick your ultimate favourites that will occupy the prime real estate on your wall.

Obviously, the light sensors sense light. So when you remove or insert a book, light floods or is blocked from that book’s sensor. The sensor sends this information to the Raspberry Pi. In response, an Arduino controls the NeoPixel strip along the ‘favourites’ shelf to indicate the book’s status.

Shelfchecker smart shelf annelynn Raspberry Pi

The book you are looking for is temporarily unavailable

Code your own library

While keeping a close eye on your favourite books, the system also allows creation of a complete library catalogue system with the help of a MySQL database. Users of the library can log into the system with a barcode scanner, and take out or return books recorded in the database guided by an LCD screen attached to the Pi.

Shelfchecker smart shelf annelynn Raspberry Pi

Beep!

I won’t go into an extensive how-to on creating MySQL databases here on the blog, because my glamourous assistant Janina has pulled up these MySQL tutorials to help you get started. Annelynn’s Github scripts are also packed with useful comments to keep you on track.

Raspberry Pi and books

We love books and libraries. And considering the growing number of Code Clubs and makespaces into libraries across the world, and the host of book-based Pi builds we’ve come across, the love seems to be mutual.

We’ve seen the Raspberry Pi introduced into the Wordery bookseller warehouse, a Pi-powered page-by-page book scanner by Jonathon Duerig, and these brilliant text-to-speech and page turner projects that use our Pis!

Did I say we love books? In fact we love them so much that members of our team have even written a few.*

If you’ve set up any sort of digital making event in a library, have in some way incorporated Raspberry Pi into your own personal book collection, or even managed to recreate the events of your favourite story using digital making, make sure to let us know in the comments below.

* Shameless plug**

Fancy adding some Pi to your home library? Check out these publications from the Raspberry Pi staff:

A Beginner’s Guide to Coding by Marc Scott

Adventures in Raspberry Pi by Carrie Anne Philbin

Getting Started with Raspberry Pi by Matt Richardson

Raspberry Pi User Guide by Eben Upton

The MagPi Magazine, Essentials Guides and Project Books

Make Your Own Game and Build Your Own Website by CoderDojo

** Shameless Pug

 

The post Shelfchecker Smart Shelf: build a home library system appeared first on Raspberry Pi.

Internet Provider Refutes RIAA’s Piracy Allegations

Post Syndicated from Ernesto original https://torrentfreak.com/internet-provider-refutes-riaas-piracy-allegations-170620/

For more than a decade copyright holders have been sending ISPs takedown notices to alert them that their subscribers are sharing copyrighted material.

Under US law, providers have to terminate the accounts of repeat infringers “in appropriate circumstances” and increasingly they are being held to this standard.

Earlier this year several major record labels, represented by the RIAA, filed a lawsuit in a Texas District Court, accusing ISP Grande Communications of failing to take action against its pirating subscribers.

“Despite their knowledge of repeat infringements, Defendants have permitted repeat infringers to use the Grande service to continue to infringe Plaintiffs’ copyrights without consequence,” the RIAA’s complaint read.

Grande and its management consulting firm Patriot, which was also sued, both disagree and have filed a motion to dismiss at the court this week. Grande argues that it doesn’t encourage any of its customers to download copyrighted works, and that it has no control over the content subscribers access.

The Internet provider doesn’t deny that it has received millions of takedown notices through the piracy tracking company Rightscorp. However, it believes that these notices are flawed as Rightscorp is incapable of monitoring actual copyright infringements.

“These notices are so numerous and so lacking in specificity, that it is infeasible for Grande to devote the time and resources required to meaningfully investigate them. Moreover, the system that Rightscorp employs to generate its notices is incapable of detecting actual infringement and, therefore, is incapable of generating notices that reflect real infringement,” Grande writes.

Grande says that if they acted on these notices without additional proof, its subscribers could lose their Internet access even though they are using it for legal purposes.

“To merely treat these allegations as true without investigation would be a disservice to Grande’s subscribers, who would run the risk of having their Internet service permanently terminated despite using Grande’s services for completely legitimate purposes.”

Even if the notices were able to prove actual infringement, they would still fail to identify the infringer, according to the ISP. The notices identify IP-addresses which may have been used by complete strangers, who connected to the network without permission.

The Internet provider admits that online copyright infringement is a real problem. But, they see themselves as a victim of this problem, not a perpetrator, as the record labels suggest.

“Grande does not profit or receive any benefit from subscribers that may engage in such infringing activity using its network. To the contrary, Grande suffers demonstrable losses as a direct result of purported copyright infringement conducted on its network.

“To hold Grande liable for copyright infringement simply because ‘something must be done’ to address this growing problem is to hold the wrong party accountable,” Grande adds.

In common with the previous case against Cox Communications, Rightscorp’s copyright infringement notices are once again at the center of a prominent lawsuit. According to Grande, Rightscorp’s system can’t prove that infringing content was actually downloaded by third parties, only that it was made available.

The Internet provider sees the lacking infringement notices as a linchpin that, if pulled, will take the entire case down.

It’s expected that, if the case moves forward, both parties will do all they can to show that the evidence is sufficient, or not. In the Cox lawsuit, this was the case, but that verdict is currently being appealed.

Grande Communication’s full motion to dismiss is avalaible here (pdf).

Source: TF, for the latest info on copyright, file-sharing, torrent sites and ANONYMOUS VPN services.

All Systems Go! 2017 CfP Open

Post Syndicated from Lennart Poettering original http://0pointer.net/blog/all-systems-go-2017-cfp-open.html

The All Systems Go! 2017 Call for Participation is Now Open!

We’d like to invite presentation proposals for All Systems Go! 2017!

All Systems Go! is an Open Source community conference focused on the projects and technologies at the foundation of modern Linux systems — specifically low-level user-space technologies. Its goal is to provide a friendly and collaborative gathering place for individuals and communities working to push these technologies forward.

All Systems Go! 2017 takes place in Berlin, Germany on October 21st+22nd.

All Systems Go! is a 2-day event with 2-3 talks happening in parallel. Full presentation slots are 30-45 minutes in length and lightning talk slots are 5-10 minutes.

We are now accepting submissions for presentation proposals. In particular, we are looking for sessions including, but not limited to, the following topics:

  • Low-level container executors and infrastructure
  • IoT and embedded OS infrastructure
  • OS, container, IoT image delivery and updating
  • Building Linux devices and applications
  • Low-level desktop technologies
  • Networking
  • System and service management
  • Tracing and performance measuring
  • IPC and RPC systems
  • Security and Sandboxing

While our focus is definitely more on the user-space side of things, talks about kernel projects are welcome too, as long as they have a clear and direct relevance for user-space.

Please submit your proposals by September 3rd. Notification of acceptance will be sent out 1-2 weeks later.

To submit your proposal now please visit our CFP submission web site.

For further information about All Systems Go! visit our conference web site.

systemd.conf will not take place this year in lieu of All Systems Go!. All Systems Go! welcomes all projects that contribute to Linux user space, which, of course, includes systemd. Thus, anything you think was appropriate for submission to systemd.conf is also fitting for All Systems Go!

New – Managed Device Authentication for Amazon WorkSpaces

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/new-managed-device-authentication-for-amazon-workspaces/

Amazon WorkSpaces allows you to access a virtual desktop in the cloud from the web and from a wide variety of desktop and mobile devices. This flexibility makes WorkSpaces ideal for environments where users have the ability to use their existing devices (often known as BYOD, or Bring Your Own Device). In these environments, organizations sometimes need the ability to manage the devices which can access WorkSpaces. For example, they may have to regulate access based on the client device operating system, version, or patch level in order to help meet compliance or security policy requirements.

Managed Device Authentication
Today we are launching device authentication for WorkSpaces. You can now use digital certificates to manage client access from Apple OSX and Microsoft Windows. You can also choose to allow or block access from iOS, Android, Chrome OS, web, and zero client devices. You can implement policies to control which device types you want to allow and which ones you want to block, with control all the way down to the patch level. Access policies are set for each WorkSpaces directory. After you have set the policies, requests to connect to WorkSpaces from a client device are assessed and either blocked or allowed. In order to make use of this feature, you will need to distribute certificates to your client devices using Microsoft System Center Configuration Manager or a mobile device management (MDM) tool.

Here’s how you set your access control options from the WorkSpaces Console:

Here’s what happens if a client is not authorized to connect:

 

Available Today
This feature is now available in all Regions where WorkSpaces is available.

Jeff;

 

[$] Preventing stack guard-page hopping

Post Syndicated from corbet original https://lwn.net/Articles/725832/rss

Normally, the -rc6 kernel testing release is not the place where one would
expect to find a 900-line memory-management change. As it happens, though,
such a change was quietly merged immediately prior to the 4.12-rc6 release; indeed, it may have been the
real reason behind 4.12-rc6 coming out some hours later than would have
been expected. This change is important, though, in that it addresses a
newly publicized security threat
that, it seems, is being actively
exploited.

[$] User-space access to WMI functions

Post Syndicated from corbet original https://lwn.net/Articles/725725/rss

Windows Management Instrumentation (WMI) is a vaguely defined mechanism for
the control of platform-specific devices; laptop functions like special
buttons, LEDs, and the backlight are often controlled through WMI
interfaces. On Linux, access to WMI functions is restricted to the kernel,
while Windows allows user space to use them as well. A recent proposal to
make WMI functions available to user space in Linux as well spawned a
slow-moving conversation that turned on a couple of interesting questions —
only one of which was anticipated in the proposal itself.

Debian Edu / Skolelinux Stretch released

Post Syndicated from ris original https://lwn.net/Articles/725828/rss

Debian Edu, also known as Skolelinux, is a Debian derivative aimed at
making it easy to administrate a computer lab or a whole school network.
Version 9 “Stretch” has been released. “Would you like to install
servers, workstations and laptops which will then work together? Do you want the
stability of Debian with network services already preconfigured? Do you
wish to have a web-based tool to manage systems and several hundred or even
more user accounts? Have you asked yourself if and how older computers
could be used? Then Debian Edu is for you.

The Pirate Bay Isn’t Affected By Adverse Court Rulings – Everyone Else Is

Post Syndicated from Andy original https://torrentfreak.com/the-pirate-bay-isnt-affected-by-adverse-court-rulings-everyone-else-is-170618/

For more than a decade The Pirate Bay has been the world’s most controversial site. Delivering huge quantities of copyrighted content to the masses, the platform is revered and reviled across the copyright spectrum.

Its reputation is one of a defiant Internet swashbuckler, but due to changes in how the site has been run in more recent times, its current philosophy is more difficult to gauge. What has never been in doubt, however, is the site’s original intent to be as provocative as possible.

Through endless publicity stunts, some real, some just for the ‘lulz’, The Pirate Bay managed to attract a massive audience, all while incurring the wrath of every major copyright holder in the world.

Make no mistake, they all queued up to strike back, but every subsequent rightsholder action was met by a Pirate Bay middle finger, two fingers, or chin flick, depending on the mood of the day. This only served to further delight the masses, who happily spread the word while keeping their torrents flowing.

This vicious circle of being targeted by the entertainment industries, mocking them, and then reaping the traffic benefits, developed into the cheapest long-term marketing campaign the Internet had ever seen. But nothing is ever truly for free and there have been consequences.

After taunting Hollywood and the music industry with its refusals to capitulate, endless legal action that the site would have ordinarily been forced to participate in largely took place without The Pirate Bay being present. It doesn’t take a law degree to work out what happened in each and every one of those cases, whatever complex route they took through the legal system. No defense, no win.

For example, the web-blocking phenomenon across the UK, Europe, Asia and Australia was driven by the site’s absolute resilience and although there would clearly have been other scapegoats had The Pirate Bay disappeared, the site was the ideal bogeyman the copyright lobby required to move forward.

Filing blocking lawsuits while bringing hosts, advertisers, and ISPs on board for anti-piracy initiatives were also made easier with the ‘evil’ Pirate Bay still online. Immune from every anti-piracy technique under the sun, the existence of the platform in the face of all onslaughts only strengthened the cases of those arguing for even more drastic measures.

Over a decade, this has meant a significant tightening of the sharing and streaming climate. Without any big legislative changes but plenty of case law against The Pirate Bay, web-blocking is now a walk in the park, ad hoc domain seizures are a fairly regular occurrence, and few companies want to host sharing sites. Advertisers and brands are also hesitant over where they place their ads. It’s a very different world to the one of 10 years ago.

While it would be wrong to attribute every tightening of the noose to the actions of The Pirate Bay, there’s little doubt that the site and its chaotic image played a huge role in where copyright enforcement is today. The platform set out to provoke and succeeded in every way possible, gaining supporters in their millions. It could also be argued it kicked a hole in a hornets’ nest, releasing the hell inside.

But perhaps the site’s most amazing achievement is the way it has managed to stay online, despite all the turmoil.

This week yet another ruling, this time from the powerful European Court of Justice, found that by offering links in the manner it does, The Pirate Bay and other sites are liable for communicating copyright works to the public. Of course, this prompted the usual swathe of articles claiming that this could be the final nail in the site’s coffin.

Wrong.

In common with every ruling, legal defeat, and legislative restriction put in place due to the site’s activities, this week’s decision from the ECJ will have zero effect on the Pirate Bay’s availability. For right or wrong, the site was breaking the law long before this ruling and will continue to do so until it decides otherwise.

What we have instead is a further tightened legal landscape that will have a lasting effect on everything BUT the site, including weaker torrent sites, Internet users, and user-uploaded content sites such as YouTube.

With The Pirate Bay carrying on regardless, that is nothing short of remarkable.

Source: TF, for the latest info on copyright, file-sharing, torrent sites and ANONYMOUS VPN services.

Digital painter rundown

Post Syndicated from Eevee original https://eev.ee/blog/2017/06/17/digital-painter-rundown/

Another patron post! IndustrialRobot asks:

You should totally write about drawing/image manipulation programs! (Inspired by https://eev.ee/blog/2015/05/31/text-editor-rundown/)

This is a little trickier than a text editor comparison — while most text editors are cross-platform, quite a few digital art programs are not. So I’m effectively unable to even try a decent chunk of the offerings. I’m also still a relatively new artist, and image editors are much harder to briefly compare than text editors…

Right, now that your expectations have been suitably lowered:

Krita

I do all of my digital art in Krita. It’s pretty alright.

Okay so Krita grew out of Calligra, which used to be KOffice, which was an office suite designed for KDE (a Linux desktop environment). I bring this up because KDE has a certain… reputation. With KDE, there are at least three completely different ways to do anything, each of those ways has ludicrous amounts of customization and settings, and somehow it still can’t do what you want.

Krita inherits this aesthetic by attempting to do literally everything. It has 17 different brush engines, more than 70 layer blending modes, seven color picker dockers, and an ungodly number of colorspaces. It’s clearly intended primarily for drawing, but it also supports animation and vector layers and a pretty decent spread of raster editing tools. I just right now discovered that it has Photoshop-like “layer styles” (e.g. drop shadow), after a year and a half of using it.

In fairness, Krita manages all of this stuff well enough, and (apparently!) it manages to stay out of your way if you’re not using it. In less fairness, they managed to break erasing with a Wacom tablet pen for three months?

I don’t want to rag on it too hard; it’s an impressive piece of work, and I enjoy using it! The emotion it evokes isn’t so much frustration as… mystified bewilderment.

I once filed a ticket suggesting the addition of a brush size palette — a panel showing a grid of fixed brush sizes that makes it easy to switch between known sizes with a tablet pen (and increases the chances that you’ll be able to get a brush back to the right size again). It’s a prominent feature of Paint Tool SAI and Clip Studio Paint, and while I’ve never used either of those myself, I’ve seen a good few artists swear by it.

The developer response was that I could emulate the behavior by creating brush presets. But that’s flat-out wrong: getting the same effect would require creating a ton of brush presets for every brush I have, plus giving them all distinct icons so the size is obvious at a glance. Even then, it would be much more tedious to use and fill my presets with junk.

And that sort of response is what’s so mysterious to me. I’ve never even been able to use this feature myself, but a year of amateur painting with Krita has convinced me that it would be pretty useful. But a developer didn’t see the use and suggested an incredibly tedious alternative that only half-solves the problem and creates new ones. Meanwhile, of the 28 existing dockable panels, a quarter of them are different ways to choose colors.

What is Krita trying to be, then? What does Krita think it is? Who precisely is the target audience? I have no idea.


Anyway, I enjoy drawing in Krita well enough. It ships with a respectable set of brushes, and there are plenty more floating around. It has canvas rotation, canvas mirroring, perspective guide tools, and other art goodies. It doesn’t colordrop on right click by default, which is arguably a grave sin (it shows a customizable radial menu instead), but that’s easy to rebind. It understands having a background color beneath a bottom transparent layer, which is very nice. You can also toggle any brush between painting and erasing with the press of a button, and that turns out to be very useful.

It doesn’t support infinite canvases, though it does offer a one-click button to extend the canvas in a given direction. I’ve never used it (and didn’t even know what it did until just now), but would totally use an infinite canvas.

I haven’t used the animation support too much, but it’s pretty nice to have. Granted, the only other animation software I’ve used is Aseprite, so I don’t have many points of reference here. It’s a relatively new addition, too, so I assume it’ll improve over time.

The one annoyance I remember with animation was really an interaction with a larger annoyance, which is: working with selections kind of sucks. You can’t drag a selection around with the selection tool; you have to switch to the move tool. That would be fine if you could at least drag the selection ring around with the selection tool, but you can’t do that either; dragging just creates a new selection.

If you want to copy a selection, you have to explicitly copy it to the clipboard and paste it, which creates a new layer. Ctrl-drag with the move tool doesn’t work. So then you have to merge that layer down, which I think is where the problem with animation comes in: a new layer is non-animated by default, meaning it effectively appears in any frame, so simply merging it down with merge it onto every single frame of the layer below. And you won’t even notice until you switch frames or play back the animation. Not ideal.

This is another thing that makes me wonder about Krita’s sense of identity. It has a lot of fancy general-purpose raster editing features that even GIMP is still struggling to implement, like high color depth support and non-destructive filters, yet something as basic as working with selections is clumsy. (In fairness, GIMP is a bit clumsy here too, but it has a consistent notion of “floating selection” that’s easy enough to work with.)

I don’t know how well Krita would work as a general-purpose raster editor; I’ve never tried to use it that way. I can’t think of anything obvious that’s missing. The only real gotcha is that some things you might expect to be tools, like smudge or clone, are just types of brush in Krita.

GIMP

Ah, GIMP — open source’s answer to Photoshop.

It’s very obviously intended for raster editing, and I’m pretty familiar with it after half a lifetime of only using Linux. I even wrote a little Scheme script for it ages ago to automate some simple edits to a couple hundred files, back before I was aware of ImageMagick. I don’t know what to say about it, specifically; it’s fairly powerful and does a wide variety of things.

In fact I’d say it’s almost frustratingly intended for raster editing. I used GIMP in my first attempts at digital painting, before I’d heard of Krita. It was okay, but so much of it felt clunky and awkward. Painting is split between a pencil tool, a paintbrush tool, and an airbrush tool; I don’t really know why. The default brushes are largely uninteresting. Instead of brush presets, there are tool presets that can be saved for any tool; it’s a neat idea, but doesn’t feel like a real substitute for brush presets.

Much of the same functionality as Krita is there, but it’s all somehow more clunky. I’m sure it’s possible to fiddle with the interface to get something friendlier for painting, but I never really figured out how.

And then there’s the surprising stuff that’s missing. There’s no canvas rotation, for example. There’s only one type of brush, and it just stamps the same pattern along a path. I don’t think it’s possible to smear or blend or pick up color while painting. The only way to change the brush size is via the very sensitive slider on the tool options panel, which I remember being a little annoying with a tablet pen. Also, you have to specifically enable tablet support? It’s not difficult or anything, but I have no idea why the default is to ignore tablet pressure and treat it like a regular mouse cursor.

As I mentioned above, there’s also no support for high color depth or non-destructive editing, which is honestly a little embarrassing. Those are the major things Serious Professionals™ have been asking for for ages, and GIMP has been trying to provide them, but it’s taking a very long time. The first signs of GEGL, a new library intended to provide these features, appeared in GIMP 2.6… in 2008. The last major release was in 2012. GIMP has been working on this new plumbing for almost as long as Krita’s entire development history. (To be fair, Krita has also raised almost €90,000 from three Kickstarters to fund its development; I don’t know that GIMP is funded at all.)

I don’t know what’s up with GIMP nowadays. It’s still under active development, but the exact status and roadmap are a little unclear. I still use it for some general-purpose editing, but I don’t see any reason to use it to draw.

I do know that canvas rotation will be in the next release, and there was some experimentation with embedding MyPaint’s brush engine (though when I tried it it was basically unusable), so maybe GIMP is interested in wooing artists? I guess we’ll see.

MyPaint

Ah, MyPaint. I gave it a try once. Once.

It’s a shame, really. It sounds pretty great: specifically built for drawing, has very powerful brushes, supports an infinite canvas, supports canvas rotation, has a simple UI that gets out of your way. Perfect.

Or so it seems. But in MyPaint’s eagerness to shed unnecessary raster editing tools, it forgot a few of the more useful ones. Like selections.

MyPaint has no notion of a selection, nor of copy/paste. If you want to move a head to align better to a body, for example, the sanctioned approach is to duplicate the layer, erase the head from the old layer, erase everything but the head from the new layer, then move the new layer.

I can’t find anything that resembles HSL adjustment, either. I guess the workaround for that is to create H/S/L layers and floodfill them with different colors until you get what you want.

I can’t work seriously without these basic editing tools. I could see myself doodling in MyPaint, but Krita works just as well for doodling as for serious painting, so I’ve never gone back to it.

Drawpile

Drawpile is the modern equivalent to OpenCanvas, I suppose? It lets multiple people draw on the same canvas simultaneously. (I would not recommend it as a general-purpose raster editor.)

It’s a little clunky in places — I sometimes have bugs where keyboard focus gets stuck in the chat, or my tablet cursor becomes invisible — but the collaborative part works surprisingly well. It’s not a brush powerhouse or anything, and I don’t think it allows textured brushes, but it supports tablet pressure and canvas rotation and locked alpha and selections and whatnot.

I’ve used it a couple times, and it’s worked well enough that… well, other people made pretty decent drawings with it? I’m not sure I’ve managed yet. And I wouldn’t use it single-player. Still, it’s fun.

Aseprite

Aseprite is for pixel art so it doesn’t really belong here at all. But it’s very good at that and I like it a lot.

That’s all

I can’t name any other serious contender that exists for Linux.

I’m dimly aware of a thing called “Photo Shop” that’s more intended for photos but functions as a passable painter. More artists seem to swear by Paint Tool SAI and Clip Studio Paint. Also there’s Paint.NET, but I have no idea how well it’s actually suited for painting.

And that’s it! That’s all I’ve got. Krita for drawing, GIMP for editing, Drawpile for collaborative doodling.

Visualize and Monitor Amazon EC2 Events with Amazon CloudWatch Events and Amazon Kinesis Firehose

Post Syndicated from Karan Desai original https://aws.amazon.com/blogs/big-data/visualize-and-monitor-amazon-ec2-events-with-amazon-cloudwatch-events-and-amazon-kinesis-firehose/

Monitoring your AWS environment is important for security, performance, and cost control purposes. For example, by monitoring and analyzing API calls made to your Amazon EC2 instances, you can trace security incidents and gain insights into administrative behaviors and access patterns. The kinds of events you might monitor include console logins, Amazon EBS snapshot creation/deletion/modification, VPC creation/deletion/modification, and instance reboots, etc.

In this post, I show you how to build a near real-time API monitoring solution for EC2 events using Amazon CloudWatch Events and Amazon Kinesis Firehose. Please be sure to have Amazon CloudTrail enabled in your account.

  • CloudWatch Events offers a near real-time stream of system events that describe changes in AWS resources. CloudWatch Events now supports Kinesis Firehose as a target.
  • Kinesis Firehose is a fully managed service for continuously capturing, transforming, and delivering data in minutes to storage and analytics destinations such as Amazon S3, Amazon Kinesis Analytics, Amazon Redshift, and Amazon Elasticsearch Service.

Walkthrough

For this walkthrough, you create a CloudWatch event rule that matches specific EC2 events such as:

  • Starting, stopping, and terminating an instance
  • Creating and deleting VPC route tables
  • Creating and deleting a security group
  • Creating, deleting, and modifying instance volumes and snapshots

Your CloudWatch event target is a Kinesis Firehose delivery stream that delivers this data to an Elasticsearch cluster, where you set up Kibana for visualization. Using this solution, you can easily load and visualize EC2 events in minutes without setting up complicated data pipelines.

Set up the Elasticsearch cluster

Create the Amazon ES domain in the Amazon ES console, or by using the create-elasticsearch-domain command in the AWS CLI.

This example uses the following configuration:

  • Domain Name: esLogSearch
  • Elasticsearch Version: 1
  • Instance Count: 2
  • Instance type:elasticsearch
  • Enable dedicated master: true
  • Enable zone awareness: true
  • Restrict Amazon ES to an IP-based access policy

Other settings are left as the defaults.

Create a Kinesis Firehose delivery stream

In the Kinesis Firehose console, create a new delivery stream with Amazon ES as the destination. For detailed steps, see Create a Kinesis Firehose Delivery Stream to Amazon Elasticsearch Service.

Set up CloudWatch Events

Create a rule, and configure the event source and target. You can choose to configure multiple event sources with several AWS resources, along with options to specify specific or multiple event types.

In the CloudWatch console, choose Events.

For Service Name, choose EC2.

In Event Pattern Preview, choose Edit and copy the pattern below. For this walkthrough, I selected events that are specific to the EC2 API, but you can modify it to include events for any of your AWS resources.

 

{
	"source": [
		"aws.ec2"
	],
	"detail-type": [
		"AWS API Call via CloudTrail"
	],
	"detail": {
		"eventSource": [
			"ec2.amazonaws.com"
		],
		"eventName": [
			"RunInstances",
			"StopInstances",
			"StartInstances",
			"CreateFlowLogs",
			"CreateImage",
			"CreateNatGateway",
			"CreateVpc",
			"DeleteKeyPair",
			"DeleteNatGateway",
			"DeleteRoute",
			"DeleteRouteTable",
"CreateSnapshot",
"DeleteSnapshot",
			"DeleteVpc",
			"DeleteVpcEndpoints",
			"DeleteSecurityGroup",
			"ModifyVolume",
			"ModifyVpcEndpoint",
			"TerminateInstances"
		]
	}
}

The following screenshot shows what your event looks like in the console.

Next, choose Add target and select the delivery stream that you just created.

Set up Kibana on the Elasticsearch cluster

Amazon ES provides a default installation of Kibana with every Amazon ES domain. You can find the Kibana endpoint on your domain dashboard in the Amazon ES console. You can restrict Amazon ES access to an IP-based access policy.

In the Kibana console, for Index name or pattern, type log. This is the name of the Elasticsearch index.

For Time-field name, choose @time.

To view the events, choose Discover.

The following chart demonstrates the API operations and the number of times that they have been triggered in the past 12 hours.

Summary

In this post, you created a continuous, near real-time solution to monitor various EC2 events such as starting and shutting down instances, creating VPCs, etc. Likewise, you can build a continuous monitoring solution for all the API operations that are relevant to your daily AWS operations and resources.

With Kinesis Firehose as a new target for CloudWatch Events, you can retrieve, transform, and load system events to the storage and analytics destination of your choice in minutes, without setting up complicated data pipelines.

If you have any questions or suggestions, please comment below.


Additional Reading

Learn how to build a serverless architecture to analyze Amazon CloudFront access logs using AWS Lambda, Amazon Athena, and Amazon Kinesis Analytics

 

 

 

Pirate Bay Ruling is Bad News For Google & YouTube, Experts Says

Post Syndicated from Andy original https://torrentfreak.com/pirate-bay-ruling-is-bad-news-for-google-youtube-experts-says-170615/

After years of legal wrangling, yesterday the European Court of Justice handed down a decision in the case between Dutch anti-piracy outfit BREIN and ISPs Ziggo and XS4ALL.

BREIN had demanded that the ISPs block The Pirate Bay, but both providers dug in their heels, forcing the case through the Supreme Court and eventually the ECJ.

For BREIN, yesterday’s decision will have been worth the wait. Although The Pirate Bay does not provide the content that’s ultimately downloaded and shared by its users, the ECJ said that it plays an important role in how that content is presented.

“Whilst it accepts that the works in question are placed online by the users, the Court highlights the fact that the operators of the platform play an essential role in making those works available,” the Court said.

With that established the all-important matter is whether by providing such a platform, the operators of The Pirate Bay are effectively engaging in a “communication to the public” of copyrighted works. According to the ECJ, that’s indeed the case.

“The Court holds that the making available and management of an online sharing platform must be considered to be an act of communication for the purposes of the directive,” the ECJ said.

Add into the mix that The Pirate Bay generates profit from its activities and there’s a potent case for copyright liability.

While the case was about The Pirate Bay, ECJ rulings tend to have an effect far beyond individual cases. That’s certainly the opinion of Enzo Mazza, chief at Italian anti-piracy group FIMI.

“The ruling will have a major impact on the way that entities like Google operate, because it will expose them to a greater and more direct responsibility,” Mazza told La Repubblica.

“So far, Google has worked against piracy by eliminating illegal content after it gets reported. But that is not enough. It is a fairly ineffective intervention.”

Mazza says that platforms like Google, YouTube, and thousands of similar sites that help to organize and curate user-uploaded content are somewhat similar to The Pirate Bay. In any event, they are not neutral intermediaries, he insists.

The conclusion that the decision is bad for platforms like YouTube is shared by Fulvio Sarzana, a lawyer with Sarzana and Partners, a law firm specializing in Internet and copyright disputes.

“In the ruling, the Court has in fact attributed, for the first time, secondary liability to sharing platforms due to the violation of copyrights carried out by the users of a platform,” Sarzana informs TF.

“This will have consequences for video-sharing platforms and user-generated content sites like YouTube, but it excludes responsibility for platforms that play a purely passive role, without affecting users’ content. This the case with cyberlockers, for example.”

Sarzana says that “unfortunate judgments” like this should be expected, until the approval of a new European copyright law. Enzo Mazza, on the other hand, feels that the copyright reform debate should take account of this ruling when formulating legislation to stop platforms like YouTube exploiting copyright works without an appropriate license.

Source: TF, for the latest info on copyright, file-sharing, torrent sites and ANONYMOUS VPN services.

New – Auto Scaling for Amazon DynamoDB

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/new-auto-scaling-for-amazon-dynamodb/

Amazon DynamoDB has more than one hundred thousand customers, spanning a wide range of industries and use cases. These customers depend on DynamoDB’s consistent performance at any scale and presence in 16 geographic regions around the world. A recent trend we’ve been observing is customers using DynamoDB to power their serverless applications. This is a good match: with DynamoDB, you don’t have to think about things like provisioning servers, performing OS and database software patching, or configuring replication across availability zones to ensure high availability – you can simply create tables and start adding data, and let DynamoDB handle the rest.

DynamoDB provides a provisioned capacity model that lets you set the amount of read and write capacity required by your applications. While this frees you from thinking about servers and enables you to change provisioning for your table with a simple API call or button click in the AWS Management Console, customers have asked us how we can make managing capacity for DynamoDB even easier.

Today we are introducing Auto Scaling for DynamoDB to help automate capacity management for your tables and global secondary indexes. You simply specify the desired target utilization and provide upper and lower bounds for read and write capacity. DynamoDB will then monitor throughput consumption using Amazon CloudWatch alarms and then will adjust provisioned capacity up or down as needed. Auto Scaling will be on by default for all new tables and indexes, and you can also configure it for existing ones.

Even if you’re not around, DynamoDB Auto Scaling will be monitoring your tables and indexes to automatically adjust throughput in response to changes in application traffic. This can make it easier to administer your DynamoDB data, help you maximize availability for your applications, and help you reduce your DynamoDB costs.

Let’s see how it works…

Using Auto Scaling
The DynamoDB Console now proposes a comfortable set of default parameters when you create a new table. You can accept them as-is or you can uncheck Use default settings and enter your own parameters:

Here’s how you enter your own parameters:

Target utilization is expressed in terms of the ratio of consumed capacity to provisioned capacity. The parameters above would allow for sufficient headroom to allow consumed capacity to double due to a burst in read or write requests (read Capacity Unit Calculations to learn more about the relationship between DynamoDB read and write operations and provisioned capacity). Changes in provisioned capacity take place in the background.

Auto Scaling in Action
In order to see this important new feature in action, I followed the directions in the Getting Started Guide. I launched a fresh EC2 instance, installed (sudo pip install boto3) and configured (aws configure) the AWS SDK for Python. Then I used the code in the Python and DynamoDB section to create and populate a table with some data, and manually configured the table for 5 units each of read and write capacity.

I took a quick break in order to have clean, straight lines for the CloudWatch metrics so that I could show the effect of Auto Scaling. Here’s what the metrics look like before I started to apply a load:

I modified the code in Step 3 to continually issue queries for random years in the range of 1920 to 2007, ran a single copy of the code, and checked the read metrics a minute or two later:

The consumed capacity is higher than the provisioned capacity, resulting in a large number of throttled reads. Time for Auto Scaling!

I returned to the console and clicked on the Capacity tab for my table. Then I clicked on Read capacity, accepted the default values, and clicked on Save:

DynamoDB created a new IAM role (DynamoDBAutoscaleRole) and a pair of CloudWatch alarms to manage the Auto Scaling of read capacity:

DynamoDB Auto Scaling will manage the thresholds for the alarms, moving them up and down as part of the scaling process. The first alarm was triggered and the table state changed to Updating while additional read capacity was provisioned:

The change was visible in the read metrics within minutes:

I started a couple of additional copies of my modified query script and watched as additional capacity was provisioned, as indicated by the red line:

I killed all of the scripts and turned my attention to other things while waiting for the scale-down alarm to trigger. Here’s what I saw when I came back:

The next morning I checked my Scaling activities and saw that the alarm had triggered several more times overnight:

This was also visible in the metrics:

Until now, you would prepare for this situation by setting your read capacity well about your expected usage, and pay for the excess capacity (the space between the blue line and the red line). Or, you might set it too low, forget to monitor it, and run out of capacity when traffic picked up. With Auto Scaling you can get the best of both worlds: an automatic response when an increase in demand suggests that more capacity is needed, and another automated response when the capacity is no longer needed.

Things to Know
DynamoDB Auto Scaling is designed to accommodate request rates that vary in a somewhat predictable, generally periodic fashion. If you need to accommodate unpredictable bursts of read activity, you should use Auto Scaling in combination with DAX (read Amazon DynamoDB Accelerator (DAX) – In-Memory Caching for Read-Intensive Workloads to learn more). Also, the AWS SDKs will detect throttled read and write requests and retry them after a suitable delay.

I mentioned the DynamoDBAutoscaleRole earlier. This role provides Auto Scaling with the privileges that it needs to have in order for it to be able to scale your tables and indexes up and down. To learn more about this role and the permissions that it uses, read Grant User Permissions for DynamoDB Auto Scaling.

Auto Scaling has complete CLI and API support, including the ability to enable and disable the Auto Scaling policies. If you have some predictable, time-bound spikes in traffic, you can programmatically disable an Auto Scaling policy, provision higher throughput for a set period of time, and then enable Auto Scaling again later.

As noted on the Limits in DynamoDB page, you can increase provisioned capacity as often as you would like and as high as you need (subject to per-account limits that we can increase on request). You can decrease capacity up to nine times per day for each table or global secondary index.

You pay for the capacity that you provision, at the regular DynamoDB prices. You can also purchase DynamoDB Reserved Capacity to further savings.

Available Now
This feature is available now in all regions and you can start using it today!

Jeff;