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Kotlin and Groovy JVM Languages with AWS Lambda

Post Syndicated from Juan Villa original https://aws.amazon.com/blogs/compute/kotlin-and-groovy-jvm-languages-with-aws-lambda/

Juan Villa – Partner Solutions Architect


When most people hear “Java” they think of Java the programming language. Java is a lot more than a programming language, it also implies a larger ecosystem including the Java Virtual Machine (JVM). Java, the programming language, is just one of the many languages that can be compiled to run on the JVM. Some of the most popular JVM languages, other than Java, are Clojure, Groovy, Scala, Kotlin, JRuby, and Jython (see this link for a list of more JVM languages).

Did you know that you can compile and subsequently run all these languages on AWS Lambda?

AWS Lambda supports the Java 8 runtime, but this does not mean you are limited to the Java language. The Java 8 runtime is capable of running JVM languages such as Kotlin and Groovy once they have been compiled and packaged as a “fat” JAR (a JAR file containing all necessary dependencies and classes bundled in).

In this blog post we’ll work through building AWS Lambda functions in both Kotlin and Groovy programming languages. To compile and package our projects we will use Gradle build tool.

To follow along, please clone the Git repository available at GitHub here. Also, I recommend using an Integrated Development Environment (IDE) such as JetBrain’s IntelliJ IDEA, this is the IDE I used while working on these projects.


Kotlin is a statically-typed JVM language designed and developed by JetBrains (one of our Amazon Partner Network Technology partners) and the open source community. Compared to Java the programming language, Kotlin has additional powerful language features such as: Data Classes, Default Arguments, Extensions, Elvis Operator, and Destructuring Declarations. This is a just a short list of Kotlin’s powerful language features. For a more thorough list of features, and how to use them, refer to the full documentation of the Kotlin language.

Let’s jump right into the code and see what an AWS Lambda function looks like in Kotlin.

package com.aws.blog.jvmlangs.kotlin

import java.io.*
import com.fasterxml.jackson.module.kotlin.*

data class HandlerInput(val who: String)
data class HandlerOutput(val message: String)

class Main {
    val mapper = jacksonObjectMapper()

    fun handler(input: InputStream, output: OutputStream): Unit {
        val inputObj = mapper.readValue<HandlerInput>(input)
        mapper.writeValue(output, HandlerOutput("Hello ${inputObj.who}"))

The above example is a very simple Hello World application that accepts as an input a JSON object containing a key called “who” and returns a JSON object containing a key called “message” with a value of “Hello {who}”.

AWS Lambda does not support serializing JSON objects into Kotlin data classes, but don’t worry! AWS Lambda supports passing an input object as a Stream, and also supports an output Stream for returning a result (see this link for more information). Combined with the Input/Output Stream form of the handler function, we are using the Jackson library with a Kotlin extension function to support serialization and deserialization of Kotlin data class types.

To get started with this example, let’s first compile and package the Kotlin project.

git clone https://github.com/awslabs/lambda-kotlin-groovy-example
cd lambda-kotlin-groovy-example/kotlin
./gradlew shadowJar

Once packaged, a JAR file containing all necessary dependencies will be available at “build/libs/ jvmlangs-kotlin-1.0-SNAPSHOT-all.jar”. Now let’s deploy this package to AWS Lambda.

To deploy the lambda function, we will be using the AWS Command Line Interface (CLI). You can find information on how to set up the AWS CLI here. This tool allows you to set up and manage AWS services via the command line.

aws lambda create-function --region us-east-1 --function-name kotlin-hello \
--zip-file fileb://build/libs/jvmlangs-kotlin-1.0-SNAPSHOT-all.jar \
--role arn:aws:iam::<account_id>:role/lambda_basic_execution \
--handler com.aws.blog.jvmlangs.kotlin.Main::handler --runtime java8 \
--timeout 15 --memory-size 128

Once deployed, we can test the function by invoking the lambda function from the CLI.

aws lambda invoke --function-name kotlin-hello --payload '{"who": "AWS Fan"}' output.txt
cat output.txt

If successful, you’ll see an output of “{"message":"Hello AWS Fan"}”.


Groovy is an optionally typed JVM language with both dynamic and static typing capabilities. Groovy is currently being supported by the Apache Software Foundation. Like Kotlin, Groovy also packs a lot of powerful features such as: Closures, Dynamic Typing, Collection Literals, String Interpolation, and Elvis Operator. This is just a short list, see the full documentation for a list of features and how to use them.

Once again, let’s jump right into the code.

package com.aws.blog.jvmlangs.groovy

class HandlerInput {
    String who
class HandlerOutput {
    String message

class Main {
    def handler(HandlerInput input) {
        return new HandlerOutput(message: "Hello ${input.who}")

Just like the Kotlin example, we have defined a function that takes a simple JSON object containing a “who” key value and build a response containing a “message” key. Note that in this case we are not using the Input/Output Stream form of the handler function, but rather we are letting AWS Lambda serialize the input JSON object into the type HandlerInput. To accomplish this, AWS Lambda uses the Jackson library and handles the serialization for us.

Let’s go ahead and compile and package this Groovy example.

git clone https://github.com/awslabs/lambda-kotlin-groovy-example
cd lambda-kotlin-groovy-example/groovy
./gradlew shadowJar

Once packaged, a JAR file containing all necessary dependencies will be available at “build/libs/ jvmlangs-groovy-1.0-SNAPSHOT-all.jar”. Now let’s deploy this package to AWS Lambda.

aws lambda create-function --region us-east-1 --function-name groovy-hello \
--zip-file fileb://build/libs/jvmlangs-groovy-1.0-SNAPSHOT-all.jar \
--role arn:aws:iam::<account_id>:role/lambda_basic_execution \
--handler com.aws.blog.jvmlangs.groovy.Main::handler --runtime java8 \
--timeout 15 --memory-size 128

Once deployed, we can test the function by invoking the lambda function from the CLI.

aws lambda invoke --function-name groovy-hello --payload '{"who": "AWS Fan"}' output.txt
cat output.txt

If successful, you’ll see an output of “{"message":"Hello AWS Fan"}”.

Gradle Build Tool

Finally, let’s touch up on how we built the JAR package from the Kotlin and Groovy sources above. To build the JARs we used the Gradle build tool. Gradle builds a project by reading instructions from a file called “build.gradle”. This is a file written in Gradle’s Groovy Domain Specific Langauge (DSL). You can find more information on the gradle build file by looking at their documentation. Let’s take a look at the Gradle build files we used for this post.

For the Kotlin example, this is the build file we used.

buildscript {
    repositories {
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "com.github.jengelman.gradle.plugins:shadow:1.2.3"

group 'com.aws.blog.jvmlangs.kotlin'
version '1.0-SNAPSHOT'

apply plugin: 'kotlin'
apply plugin: 'com.github.johnrengelman.shadow'

repositories {

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    compile "com.fasterxml.jackson.module:jackson-module-kotlin:2.8.2"

For the Groovy example this is the build file we used.

buildscript {
    repositories {
    dependencies {
        classpath 'com.github.jengelman.gradle.plugins:shadow:1.2.3'

group 'com.aws.blog.jvmlangs.groovy'
version '1.0-SNAPSHOT'

apply plugin: 'groovy'
apply plugin: 'com.github.johnrengelman.shadow'

repositories {

dependencies {
    compile 'org.codehaus.groovy:groovy-all:2.3.11'
    testCompile group: 'junit', name: 'junit', version: '4.11'

As you can see, the build files for both Kotlin and Groovy files are very similar. For the Kotlin project we define a dependency on the Jackson Kotlin module. Also, for each respective language we include the language supporting libraries (kotlin-stdlib and groovy-all respectively).

In addition, you will notice that we are using a plugin called “shadow”. We use this plugin to package all the project dependencies into one JAR by using the Gradle task “shadowJar”. You can find more information on Shadow in their documentation.

Final Words

Don’t stop here though! Take a look at other JVM languages and get them running on AWS Lambda with the Java 8 runtime. Maybe start with Clojure? or Scala?

Also take a look AWS Lambda Java libraries provided by AWS. They provide interfaces and models to make handling events from event sources easier to handle.

A Raspbian desktop update with some new programming tools

Post Syndicated from Simon Long original https://www.raspberrypi.org/blog/a-raspbian-desktop-update-with-some-new-programming-tools/

Today we’ve released another update to the Raspbian desktop. In addition to the usual small tweaks and bug fixes, the big new changes are the inclusion of an offline version of Scratch 2.0, and of Thonny (a user-friendly IDE for Python which is excellent for beginners). We’ll look at all the changes in this post, but let’s start with the biggest…

Scratch 2.0 for Raspbian

Scratch is one of the most popular pieces of software on Raspberry Pi. This is largely due to the way it makes programming accessible – while it is simple to learn, it covers many of the concepts that are used in more advanced languages. Scratch really does provide a great introduction to programming for all ages.

Raspbian ships with the original version of Scratch, which is now at version 1.4. A few years ago, though, the Scratch team at the MIT Media Lab introduced the new and improved Scratch version 2.0, and ever since we’ve had numerous requests to offer it on the Pi.

There was, however, a problem with this. The original version of Scratch was written in a language called Squeak, which could run on the Pi in a Squeak interpreter. Scratch 2.0, however, was written in Flash, and was designed to run from a remote site in a web browser. While this made Scratch 2.0 a cross-platform application, which you could run without installing any Scratch software, it also meant that you had to be able to run Flash on your computer, and that you needed to be connected to the internet to program in Scratch.

We worked with Adobe to include the Pepper Flash plugin in Raspbian, which enables Flash sites to run in the Chromium browser. This addressed the first of these problems, so the Scratch 2.0 website has been available on Pi for a while. However, it still needed an internet connection to run, which wasn’t ideal in many circumstances. We’ve been working with the Scratch team to get an offline version of Scratch 2.0 running on Pi.

Screenshot of Scratch on Raspbian

The Scratch team had created a website to enable developers to create hardware and software extensions for Scratch 2.0; this provided a version of the Flash code for the Scratch editor which could be modified to run locally rather than over the internet. We combined this with a program called Electron, which effectively wraps up a local web page into a standalone application. We ended up with the Scratch 2.0 application that you can find in the Programming section of the main menu.

Physical computing with Scratch 2.0

We didn’t stop there though. We know that people want to use Scratch for physical computing, and it has always been a bit awkward to access GPIO pins from Scratch. In our Scratch 2.0 application, therefore, there is a custom extension which allows the user to control the Pi’s GPIO pins without difficulty. Simply click on ‘More Blocks’, choose ‘Add an Extension’, and select ‘Pi GPIO’. This loads two new blocks, one to read and one to write the state of a GPIO pin.

Screenshot of new Raspbian iteration of Scratch 2, featuring GPIO pin control blocks.

The Scratch team kindly allowed us to include all the sprites, backdrops, and sounds from the online version of Scratch 2.0. You can also use the Raspberry Pi Camera Module to create new sprites and backgrounds.

This first release works well, although it can be slow for some operations; this is largely unavoidable for Flash code running under Electron. Bear in mind that you will need to have the Pepper Flash plugin installed (which it is by default on standard Raspbian images). As Pepper Flash is only compatible with the processor in the Pi 2.0 and Pi 3, it is unfortunately not possible to run Scratch 2.0 on the Pi Zero or the original models of the Pi.

We hope that this makes Scratch 2.0 a more practical proposition for many users than it has been to date. Do let us know if you hit any problems, though!

Thonny: a more user-friendly IDE for Python

One of the paths from Scratch to ‘real’ programming is through Python. We know that the transition can be awkward, and this isn’t helped by the tools available for learning Python. It’s fair to say that IDLE, the Python IDE, isn’t the most popular piece of software ever written…

Earlier this year, we reviewed every Python IDE that we could find that would run on a Raspberry Pi, in an attempt to see if there was something better out there than IDLE. We wanted to find something that was easier for beginners to use but still useful for experienced Python programmers. We found one program, Thonny, which stood head and shoulders above all the rest. It’s a really user-friendly IDE, which still offers useful professional features like single-stepping of code and inspection of variables.

Screenshot of Thonny IDE in Raspbian

Thonny was created at the University of Tartu in Estonia; we’ve been working with Aivar Annamaa, the lead developer, on getting it into Raspbian. The original version of Thonny works well on the Pi, but because the GUI is written using Python’s default GUI toolkit, Tkinter, the appearance clashes with the rest of the Raspbian desktop, most of which is written using the GTK toolkit. We made some changes to bring things like fonts and graphics into line with the appearance of our other apps, and Aivar very kindly took that work and converted it into a theme package that could be applied to Thonny.

Due to the limitations of working within Tkinter, the result isn’t exactly like a native GTK application, but it’s pretty close. It’s probably good enough for anyone who isn’t a picky UI obsessive like me, anyway! Have a look at the Thonny webpage to see some more details of all the cool features it offers. We hope that having a more usable environment will help to ease the transition from graphical languages like Scratch into ‘proper’ languages like Python.

New icons

Other than these two new packages, this release is mostly bug fixes and small version bumps. One thing you might notice, though, is that we’ve made some tweaks to our custom icon set. We wondered if the icons might look better with slightly thinner outlines. We tried it, and they did: we hope you prefer them too.

Downloading the new image

You can either download a new image from the Downloads page, or you can use apt to update:

sudo apt-get update
sudo apt-get dist-upgrade

To install Scratch 2.0:

sudo apt-get install scratch2

To install Thonny:

sudo apt-get install python3-thonny

One more thing…

Before Christmas, we released an experimental version of the desktop running on Debian for x86-based computers. We were slightly taken aback by how popular it turned out to be! This made us realise that this was something we were going to need to support going forward. We’ve decided we’re going to try to make all new desktop releases for both Pi and x86 from now on.

The version of this we released last year was a live image that could run from a USB stick. Many people asked if we could make it permanently installable, so this version includes an installer. This uses the standard Debian install process, so it ought to work on most machines. I should stress, though, that we haven’t been able to test on every type of hardware, so there may be issues on some computers. Please be sure to back up your hard drive before installing it. Unlike the live image, this will erase and reformat your hard drive, and you will lose anything that is already on it!

You can still boot the image as a live image if you don’t want to install it, and it will create a persistence partition on the USB stick so you can save data. Just select ‘Run with persistence’ from the boot menu. To install, choose either ‘Install’ or ‘Graphical install’ from the same menu. The Debian installer will then walk you through the install process.

You can download the latest x86 image (which includes both Scratch 2.0 and Thonny) from here or here for a torrent file.

One final thing

This version of the desktop is based on Debian Jessie. Some of you will be aware that a new stable version of Debian (called Stretch) was released last week. Rest assured – we have been working on porting everything across to Stretch for some time now, and we will have a Stretch release ready some time over the summer.

The post A Raspbian desktop update with some new programming tools appeared first on Raspberry Pi.

From Idea to Launch: Getting Your First Customers

Post Syndicated from Gleb Budman original https://www.backblaze.com/blog/how-to-get-your-first-customers/

line outside of Apple

After deciding to build an unlimited backup service and developing our own storage platform, the next step was to get customers and feedback. Not all customers are created equal. Let’s talk about the types, and when and how to attract them.

How to Get Your First Customers

First Step – Don’t Launch Publicly
Launch when you’re ready for the judgments of people who don’t know you at all. Until then, don’t launch. Sign up users and customers either that you know, those you can trust to cut you some slack (while providing you feedback), or at minimum those for whom you can set expectations. For months the Backblaze website was a single page with no ability to get the product and minimal info on what it would be. This is not to counter the Lean Startup ‘iterate quickly with customer feedback’ advice. Rather, this is an acknowledgement that there are different types of feedback required based on your development stage.

Sign Up Your Friends
We knew all of our first customers; they were friends, family, and previous co-workers. Many knew what we were up to and were excited to help us. No magic marketing or tech savviness was required to reach them – we just asked that they try the service. We asked them to provide us feedback on their experience and collected it through email and conversations. While the feedback wasn’t unbiased, it was nonetheless wide-ranging, real, and often insightful. These people were willing to spend time carefully thinking about their feedback and delving deeper into the conversations.

Broaden to Beta
Unless you’re famous or your service costs $1 million per customer, you’ll probably need to expand quickly beyond your friends to build a business – and to get broader feedback. Our next step was to broaden the customer base to beta users.

Opening up the service in beta provides three benefits:

  1. Air cover for the early warts. There are going to be issues, bugs, unnecessarily complicated user flows, and poorly worded text. Beta tells people, “We don’t consider the product ‘done’ and you should expect some of these issues. Please be patient with us.”
  2. A request for feedback. Some people always provide feedback, but beta communicates that you want it.
  3. An awareness opportunity. Opening up in beta provides an early (but not only) opportunity to have an announcement and build awareness.

Pitching Beta to Press
Not all press cares about, or is even willing to cover, beta products. Much of the mainstream press wants to write about services that are fully live, have scale, and are important in the marketplace. However, there are a number of sites that like to cover the leading edge – and that means covering betas. Techcrunch, Ars Technica, and SimpleHelp covered our initial private beta launch. I’ll go into the details of how to work with the press to cover your announcements in a post next month.

Private vs. Public Beta
Both private and public beta provide all three of the benefits above. The difference between the two is that private betas are much more controlled, whereas public ones bring in more users. But this isn’t an either/or – I recommend doing both.

Private Beta
For our original beta in 2008, we decided that we were comfortable with about 1,000 users subscribing to our service. That would provide us with a healthy amount of feedback and get some early adoption, while not overwhelming us or our server capacity, and equally important not causing cash flow issues from having to buy more equipment. So we decided to limit the sign-up to only the first 1,000 people who signed up; then we would shut off sign-ups for a while.

But how do you even get 1,000 people to sign up for your service? In our case, get some major publications to write about our beta. (Note: In a future post I’ll explain exactly how to find and reach out to writers. Sign up to receive all of the entrepreneurial posts in this series.)

Public Beta
For our original service (computer backup), we did not have a public beta; but when we launched Backblaze B2, we had a private and then a public beta. The private beta allowed us to work out early kinks, while the public beta brought us a more varied set of use cases. In public beta, there is no cap on the number of users that may try the service.

While this is a first-class problem to have, if your service is flooded and stops working, it’s still a problem. Think through what you will do if that happens. In our early days, when our system could get overwhelmed by volume, we had a static web page hosted with a different registrar that wouldn’t let customers sign up but would tell them when our service would be open again. When we reached a critical volume level we would redirect to it in order to at least provide status for when we could accept more customers.

Collect Feedback
Since one of the goals of betas is to get feedback, we made sure that we had our email addresses clearly presented on the site so users could send us thoughts. We were most interested in broad qualitative feedback on users’ experience, so all emails went to an internal mailing list that would be read by everyone at Backblaze.

For our B2 public and private betas, we also added an optional short survey to the sign-up process. In order to be considered for the private beta you had to fill the survey out, though we found that 80% of users continued to fill out the survey even when it was not required. This survey had both closed-end questions (“how much data do you have”) and open-ended ones (“what do you want to use cloud storage for?”).

BTW, despite us getting a lot of feedback now via our support team, Twitter, and marketing surveys, we are always open to more – you can email me directly at gleb.budman {at} backblaze.com.

Don’t Throw Away Users
Initially our backup service was available only on Windows, but we had an email sign-up list for people who wanted it for their Mac. This provided us with a sense of market demand and a ready list of folks who could be beta users and early adopters when we had a Mac version. Have a service targeted at doctors but lawyers are expressing interest? Capture that.

Product Launch

The first question is “when” to launch. Presuming your service is in ‘public beta’, what is the advantage of moving out of beta and into a “version 1.0”, “gold”, or “public availability”? That depends on your service and customer base. Some services fly through public beta. Gmail, on the other hand, was (in)famous for being in beta for 5 years, despite having over 100 million users.

The term beta says to users, “give us some leeway, but feel free to use the service”. That’s fine for many consumer apps and will have near zero impact on them. However, services aimed at businesses and government will often not be adopted with a beta label as the enterprise customers want to know the company feels the service is ‘ready’. While Backblaze started out as a purely consumer service, because it was a data backup service, it was important for customers to trust that the service was ready.

No product is bug-free. But from a product readiness perspective, the nomenclature should also be a reflection of the quality of the product. You can launch a product with one feature that works well out of beta. But a product with fifty features on which half the users will bump into problems should likely stay in beta. The customer feedback, surveys, and your own internal testing should guide you in determining this quality during the beta. Be careful about “we’ve only seen that one time” or “I haven’t been able to reproduce that on my machine”; those issues are likely to scale with customers when you launch.

Launching out of beta can be as simple as removing the beta label from the website/product. However, this can be a great time to reach out to press, write a blog post, and send an email announcement to your customers.

Consider thanking your beta testers somehow; can they get some feature turned out for free, an extension of their trial, or premium support? If nothing else, remember to thank them for their feedback. Users that signed up during your beta are likely the ones who will propel your service. They had the need and interest to both be early adopters and deal with bugs. They are likely the key to getting 1,000 true fans.

The Beginning
The title of this post was “Getting your first customers”, because getting to launch may feel like the peak of your journey when you’re pre-launch, but it really is just the beginning. It’s a step along the journey of building your business. If your launch is wildly successful, enjoy it, work to build on the momentum, but don’t lose track of building your business. If your launch is a dud, go out for a coffee with your team, say “well that sucks”, and then get back to building your business. You can learn a tremendous amount from your early customers, and they can become your biggest fans, but the success of your business will depend on what you continue to do the months and years after your launch.

The post From Idea to Launch: Getting Your First Customers appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

HiveMQ 3.2.5 released

Post Syndicated from The HiveMQ Team original http://www.hivemq.com/blog/hivemq-3-2-5-released/

The HiveMQ team is pleased to announce the availability of HiveMQ 3.2.5. This is a maintenance release for the 3.2 series and brings the following improvements:

  • Fixed an issue that caused cluster nodes to not be operational for a long time after start up
  • Fixed an issue that could cause wildcard (+ operator) subscriptions to get lost
  • Fixed an issue that could cause QoS=1 messages to get lost when using cleanSession=false and shared subscription groups
  • Fixed an issue that could cause the current session count metric to be incorrect
  • Fixed an issue that could lead to QoS=0 message to be resent incorrectly when using shared subscriptions
  • Fixed various issues that could cause false Exceptions to be logged
  • Fixed an issue that could lead to an increase in memory usage when using retained messages
  • Improved documentation
  • Improved logging
  • Performance improvements

You can download the new HiveMQ version here.

We strongly recommend to upgrade if you are an HiveMQ 3.2.x user.

Have a great day,
The HiveMQ Team

CoderDojo Coolest Projects 2017

Post Syndicated from Ben Nuttall original https://www.raspberrypi.org/blog/coderdojo-coolest-projects-2017/

When I heard we were merging with CoderDojo, I was delighted. CoderDojo is a wonderful organisation with a spectacular community, and it’s going to be great to join forces with the team and work towards our common goal: making a difference to the lives of young people by making technology accessible to them.

You may remember that last year Philip and I went along to Coolest Projects, CoderDojo’s annual event at which their global community showcase their best makes. It was awesome! This year a whole bunch of us from the Raspberry Pi Foundation attended Coolest Projects with our new Irish colleagues, and as expected, the projects on show were as cool as can be.

Coolest Projects 2017 attendee

Crowd at Coolest Projects 2017

This year’s coolest projects!

Young maker Benjamin demoed his brilliant RGB LED table tennis ball display for us, and showed off his brilliant project tutorial website codemakerbuddy.com, which he built with Python and Flask. [Click on any of the images to enlarge them.]

Coolest Projects 2017 LED ping-pong ball display
Coolest Projects 2017 Benjamin and Oly

Next up, Aimee showed us a recipes app she’d made with the MIT App Inventor. It was a really impressive and well thought-out project.

Coolest Projects 2017 Aimee's cook book
Coolest Projects 2017 Aimee's setup

This very successful OpenCV face detection program with hardware installed in a teddy bear was great as well:

Coolest Projects 2017 face detection bear
Coolest Projects 2017 face detection interface
Coolest Projects 2017 face detection database

Helen’s and Oly’s favourite project involved…live bees!

Coolest Projects 2017 live bees


Its creator, 12-year-old Amy, said she wanted to do something to help the Earth. Her project uses various sensors to record data on the bee population in the hive. An adjacent monitor displays the data in a web interface:

Coolest Projects 2017 Aimee's bees

Coolest robots

I enjoyed seeing lots of GPIO Zero projects out in the wild, including this robotic lawnmower made by Kevin and Zach:

Raspberry Pi Lawnmower

Kevin and Zach’s Raspberry Pi lawnmower project with Python and GPIO Zero, showed at CoderDojo Coolest Projects 2017

Philip’s favourite make was a Pi-powered robot you can control with your mind! According to the maker, Laura, it worked really well with Philip because he has no hair.

Philip Colligan on Twitter

This is extraordinary. Laura from @CoderDojo Romania has programmed a mind controlled robot using @Raspberry_Pi @coolestprojects

And here are some pictures of even more cool robots we saw:

Coolest Projects 2017 coolest robot no.1
Coolest Projects 2017 coolest robot no.2
Coolest Projects 2017 coolest robot no.3

Games, toys, activities

Oly and I were massively impressed with the work of Mogamad, Daniel, and Basheerah, who programmed a (borrowed) Amazon Echo to make a voice-controlled text-adventure game using Java and the Alexa API. They’ve inspired me to try something similar using the AIY projects kit and adventurelib!

Coolest Projects 2017 Mogamad, Daniel, Basheerah, Oly
Coolest Projects 2017 Alexa text-based game

Christopher Hill did a brilliant job with his Home Alone LEGO house. He used sensors to trigger lights and sounds to make it look like someone’s at home, like in the film. I should have taken a video – seeing it in action was great!

Coolest Projects 2017 Lego home alone house
Coolest Projects 2017 Lego home alone innards
Coolest Projects 2017 Lego home alone innards closeup

Meanwhile, the Northern Ireland Raspberry Jam group ran a DOTS board activity, which turned their area into a conductive paint hazard zone.

Coolest Projects 2017 NI Jam DOTS activity 1
Coolest Projects 2017 NI Jam DOTS activity 2
Coolest Projects 2017 NI Jam DOTS activity 3
Coolest Projects 2017 NI Jam DOTS activity 4
Coolest Projects 2017 NI Jam DOTS activity 5
Coolest Projects 2017 NI Jam DOTS activity 6

Creativity and ingenuity

We really enjoyed seeing so many young people collaborating, experimenting, and taking full advantage of the opportunity to make real projects. And we loved how huge the range of technologies in use was: people employed all manner of hardware and software to bring their ideas to life.

Philip Colligan on Twitter

Wow! Look at that room full of awesome young people. @coolestprojects #coolestprojects @CoderDojo

Congratulations to the Coolest Projects 2017 prize winners, and to all participants. Here are some of the teams that won in the different categories:

Coolest Projects 2017 winning team 1
Coolest Projects 2017 winning team 2
Coolest Projects 2017 winning team 3

Take a look at the gallery of all winners over on Flickr.

The wow factor

Raspberry Pi co-founder and Foundation trustee Pete Lomas came along to the event as well. Here’s what he had to say:

It’s hard to describe the scale of the event, and photos just don’t do it justice. The first thing that hit me was the sheer excitement of the CoderDojo ninjas [the children attending Dojos]. Everyone was setting up for their time with the project judges, and their pure delight at being able to show off their creations was evident in both halls. Time and time again I saw the ninjas apply their creativity to help save the planet or make someone’s life better, and it’s truly exciting that we are going to help that continue and expand.

Even after 8 hours, enthusiasm wasn’t flagging – the awards ceremony was just brilliant, with ninjas high-fiving the winners on the way to the stage. This speaks volumes about the ethos and vision of the CoderDojo founders, where everyone is a winner just by being part of a community of worldwide friends. It was a brilliant introduction, and if this weekend was anything to go by, our merger certainly is a marriage made in Heaven.

Join this awesome community!

If all this inspires you as much as it did us, consider looking for a CoderDojo near you – and sign up as a volunteer! There’s plenty of time for young people to build up skills and start working on a project for next year’s event. Check out coolestprojects.com for more information.

The post CoderDojo Coolest Projects 2017 appeared first on Raspberry Pi.

NSA Insider Security Post-Snowden

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/06/nsa_insider_sec.html

According to a recently declassified report obtained under FOIA, the NSA’s attempts to protect itself against insider attacks aren’t going very well:

The N.S.A. failed to consistently lock racks of servers storing highly classified data and to secure data center machine rooms, according to the report, an investigation by the Defense Department’s inspector general completed in 2016.


The agency also failed to meaningfully reduce the number of officials and contractors who were empowered to download and transfer data classified as top secret, as well as the number of “privileged” users, who have greater power to access the N.S.A.’s most sensitive computer systems. And it did not fully implement software to monitor what those users were doing.

In all, the report concluded, while the post-Snowden initiative — called “Secure the Net” by the N.S.A. — had some successes, it “did not fully meet the intent of decreasing the risk of insider threats to N.S.A. operations and the ability of insiders to exfiltrate data.”

Marcy Wheeler comments:

The IG report examined seven of the most important out of 40 “Secure the Net” initiatives rolled out since Snowden began leaking classified information. Two of the initiatives aspired to reduce the number of people who had the kind of access Snowden did: those who have privileged access to maintain, configure, and operate the NSA’s computer systems (what the report calls PRIVACs), and those who are authorized to use removable media to transfer data to or from an NSA system (what the report calls DTAs).

But when DOD’s inspectors went to assess whether NSA had succeeded in doing this, they found something disturbing. In both cases, the NSA did not have solid documentation about how many such users existed at the time of the Snowden leak. With respect to PRIVACs, in June 2013 (the start of the Snowden leak), “NSA officials stated that they used a manually kept spreadsheet, which they no longer had, to identify the initial number of privileged users.” The report offered no explanation for how NSA came to no longer have that spreadsheet just as an investigation into the biggest breach thus far at NSA started. With respect to DTAs, “NSA did not know how many DTAs it had because the manually kept list was corrupted during the months leading up to the security breach.”

There seem to be two possible explanations for the fact that the NSA couldn’t track who had the same kind of access that Snowden exploited to steal so many documents. Either the dog ate their homework: Someone at NSA made the documents unavailable (or they never really existed). Or someone fed the dog their homework: Some adversary made these lists unusable. The former would suggest the NSA had something to hide as it prepared to explain why Snowden had been able to walk away with NSA’s crown jewels. The latter would suggest that someone deliberately obscured who else in the building might walk away with the crown jewels. Obscuring that list would be of particular value if you were a foreign adversary planning on walking away with a bunch of files, such as the set of hacking tools the Shadow Brokers have since released, which are believed to have originated at NSA.

Read the whole thing. Securing against insiders, especially those with technical access, is difficult, but I had assumed the NSA did more post-Snowden.

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:


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.


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:

      - ./packer build -color=false packer_cis.json | tee build.log
      - 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
    - 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": [
  "source": [
  "detail": {
    "AmiStatus": [

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": {
    "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": [{
    "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": [
        "type": "shell",
        "inline": [
            "sudo pip install ansible"
        "type": "ansible-local",
        "playbook_file": "ansible/playbook.yaml",
        "role_paths": [
        "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
    # CIS Controls whitepaper:  http://bit.ly/2mGAmUc
    # AWS CIS Whitepaper:       http://bit.ly/2m2Ovrh
    # 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
    # Autofs is not installed in newer versions, let's ignore
      - 1.1.19
    # Cloudwatch Logs role configuration
      - file: /var/log/messages
        group_name: "system_logs"
    - 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.


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.



Protect Web Sites & Services Using Rate-Based Rules for AWS WAF

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/protect-web-sites-services-using-rate-based-rules-for-aws-waf/

AWS WAF (Web Application Firewall) helps to protect your application from many different types of application-layer attacks that involve requests that are malicious or malformed. As I showed you when I first wrote about this service (New – AWS WAF), you can define rules that match cross-site scripting, IP address, SQL injection, size, or content constraints:

When incoming requests match rules, actions are invoked. Actions can either allow, block, or simply count matches.

The existing rule model is powerful and gives you the ability to detect and respond to many different types of attacks. It does not, however, allow you to respond to attacks that simply consist of a large number of otherwise valid requests from a particular IP address. These requests might be a web-layer DDoS attack, a brute-force login attempt, or even a partner integration gone awry.

New Rate-Based Rules
Today we are adding Rate-based Rules to WAF, giving you control of when IP addresses are added to and removed from a blacklist, along with the flexibility to handle exceptions and special cases:

Blacklisting IP Addresses – You can blacklist IP addresses that make requests at a rate that exceeds a configured threshold rate.

IP Address Tracking– You can see which IP addresses are currently blacklisted.

IP Address Removal – IP addresses that have been blacklisted are automatically removed when they no longer make requests at a rate above the configured threshold.

IP Address Exemption – You can exempt certain IP addresses from blacklisting by using an IP address whitelist inside of the a rate-based rule. For example, you might want to allow trusted partners to access your site at a higher rate.

Monitoring & Alarming – You can watch and alarm on CloudWatch metrics that are published for each rule.

You can combine new Rate-based Rules with WAF Conditions to implement sophisticated rate-limiting strategies. For example, you could use a Rate-based Rule and a WAF Condition that matches your login pages. This would allow you to impose a modest threshold on your login pages (to avoid brute-force password attacks) and allow a more generous one on your marketing or system status pages.

Thresholds are defined in terms of the number of incoming requests from a single IP address within a 5 minute period. Once this threshold is breached, additional requests from the IP address are blocked until the request rate falls below the threshold.

Using Rate-Based Rules
Here’s how you would define a Rate-based Rule that protects the /login portion of your site. Start by defining a WAF condition that matches the desired string in the URI of the page:

Then use this condition to define a Rate-based Rule (the rate limit is expressed in terms of requests within a 5 minute interval, but the blacklisting goes in to effect as soon as the limit is breached):

With the condition and the rule in place, create a Web ACL (ProtectLoginACL) to bring it all together and to attach it to the AWS resource (a CloudFront distribution in this case):

Then attach the rule (ProtectLogin) to the Web ACL:

The resource is now protected in accord with the rule and the web ACL. You can monitor the associated CloudWatch metrics (ProtectLogin and ProtectLoginACL in this case). You could even create CloudWatch Alarms and use them to fire Lambda functions when a protection threshold is breached. The code could examine the offending IP address and make a complex, business-driven decision, perhaps adding a whitelisting rule that gives an extra-generous allowance to a trusted partner or to a user with a special payment plan.

Available Now
The new, Rate-based Rules are available now and you can start using them today! Rate-based rules are priced the same as Regular rules; see the WAF Pricing page for more info.


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#.


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);
    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())
            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);
            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.


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!

AWS Marketplace Update – SaaS Contracts in Action

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/aws-marketplace-update-saas-contracts-in-action/

AWS Marketplace lets AWS customers find and use products and services offered by members of the AWS Partner Network (APN). Some marketplace offerings are billed on an hourly basis, many with a cost-saving annual option designed to line up with the procurement cycles of our enterprise customers. Other offerings are available in SaaS (Software as a Service) form and are billed based on consumption units specified by the seller. The SaaS model (described in New – SaaS subscriptions on AWS Marketplace) give sellers the flexibility to bill for actual usage: number of active hosts, number of requests, GB of log files processed, and so forth.

Recently we extended the SaaS model with the addition of SaaS contracts, which my colleague Brad Lyman introduced in his post, Announcing SaaS Contracts, a Feature to Simplify SaaS Procurement on AWS Marketplace. The contracts give our customers the opportunity save money by setting up monthly subscriptions that can be expanded to cover a one, two, or three year contract term, with automatic, configurable renewals. Sellers can provide services that require up-front payment or that offer discounts in exchange for a usage commitment.

Since Brad has already covered the seller side of this powerful and flexible new model, I would like to show you what it is like to purchase a SaaS contract. Let’s say that I want to use Splunk Cloud. I simply search for it as usual:

I click on Splunk Cloud and see that it is available in SaaS Contract form:

I can also see and review the pricing options, noting that pricing varies by location, index volume, and subscription duration:

I click on Continue. Since I do not have a contract with Splunk for this software, I’ll be redirected to the vendor’s site to create one as part of the process. I choose my location, index volume, and contract duration, and opt for automatic renewal, and then click on Create Contract:

This sets up my subscription, and I need only set up my account with Splunk:

I click on Set Up Your Account and I am ready to move forward by setting up my custom URL on the Splunk site:

This feature is available now and you can start using it today.



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


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.

Weekly roundup: Successful juggling

Post Syndicated from Eevee original https://eev.ee/dev/2017/06/19/weekly-roundup-successful-juggling/

Despite flipping my sleep, as I seem to end up doing every month now, I’ve had a pretty solid week. We finally got our hands on a Switch, so I just played Zelda to stay up a ridiculously long time and restore my schedule pretty quickly.

  • potluck: I started building the potluck game in LÖVE, and it’s certainly come along much faster — I have map transitions, dialogue, and a couple moving platforms working. I still don’t quite know what this game is, but I’m starting to get some ideas.

    I also launched GAMES MADE QUICK??? 1½, a game jam for making a game while watching GDQ, instead of just plain watching GDQ. I intend to spend the week working on the potluck game, though I’m not sure whether I’ll finish it then.

  • fox flux: I started planning out a more interesting overworld and doodled a couple relevant tiles. Terrain is still hard. Also some more player frames.

  • art: I finally finished a glorious new banner, which now hangs proudly above my Twitter and Patreon. I did a bedtime slate doodle. I made and animated a low-poly Yoshi. I sketched Styx based on a photo.

    I keep wishing I have time to dedicate to painting experiments, but I guess this is pretty good output.

  • veekun: Wow! I touched veekun on three separate occasions. I have basic item data actually physically dumping now, I fixed some stuff with Pokémon, and I got evolutions working. Progress! Getting there! So close!

  • blog: Per request, I wrote about digital painting software, though it was hampered slightly by the fact that most of it doesn’t run on my operating system.

I seem to be maintaining tangible momentum on multiple big projects, which is fantastic. And there’s still 40% of the month left! I’m feeling pretty good about where I’m standing; if I can get potluck and veekun done soon, that’ll be a medium and a VERY LARGE weight off my shoulders.

Disney Asks Google to Remove Its Own (Invisible) Takedown Notices

Post Syndicated from Ernesto original https://torrentfreak.com/disney-asks-google-to-remove-its-own-invisible-takedown-notices-170618/

Pretty much every major copyright holder regularly reports infringing links to Google, hoping to decrease the visibility of pirated files.

Over the past several years, the search engine has had to remove more than two billion links and most of these requests have been neatly archived in the Lumen database.

Walt Disney Company is no stranger to these takedown efforts. The company has sent over 20 million takedown requests to the search engine, covering a wide variety of content. All of these notices are listed in Google’s transparency report, and copies are available at Lumen.

While this is nothing new, we recently noticed that Disney doesn’t stop at reporting direct links to traditional “pirate” sites. In fact, they recently targeted one of their own takedown notices in the Lumen database, which was sent on behalf of its daughter company Lucasfilm.

In the notice below, the media giant wants Google to remove a links to a copy of its own takedown notice, claiming that it infringes the copyright of the blockbuster “Star Wars: The Force Awakens.”

Disney vs. Disney?

This is not the first time that a company has engaged in this type of meta-censorship, it appears.

However, it’s all the more relevant this week after a German court decided that Google can be ordered to stop linking to its own takedown notices. While that suggests that Disney was right to ask for its own link to be removed, the reality is a bit more complex.

When it was still known as ChillingEffects, the Lumen Database instructed Google not to index any takedown notices. And indeed, searching for copies of takedown notices yields no result. This means that Disney asked Google to remove a search result that doesn’t exist.

Perhaps things are different in a galaxy far, far away, but Disney’s takedown notice is not only self-censorship but also entirely pointless.

Disney might be better off focusing on content that Google has actually indexed, instead of going after imaginary threats. Or put in the words of Gold Five: “Stay on Target,” Disney..

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:


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.


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.


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 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 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.

Alleged KickassTorrents Owner Considers ‘Voluntary Surrender’ to the US

Post Syndicated from Ernesto original https://torrentfreak.com/alleged-kickasstorrents-owner-considers-voluntary-surrender-to-the-us-170616/

Earlier this year a Polish court ruled that Artem Vaulin, the alleged owner of the defunct torrent site KickassTorrents, can be extradited to the United States.

The decision came as a disappointment to the defense team, which quickly announced an appeal.

Vaulin has since been released on bail and currently resides in a Warsaw apartment. His release has made it easier to communicate with his attorneys in the United States, who have started negotiations with the US Government.

While the extradition appeal is still ongoing, it now appears that under the right conditions Vaulin might consider traveling to the United States voluntarily, so he can “resolve” the pending charges.

This is what the defense team states in a motion for a status conference (pdf), which was submitted earlier this week.

“Mr. Vaulin and his counsel in the United States recently have engaged in discussions with the government to determine if the parties can resolve this matter, or at least certain significant issues,” Vaulin’s legal team writes.

This includes “…issues relating to the proper calculation of the sentencing guidelines and/or the possibility of an agreement for bond should Mr. Vaulin decide to voluntarily surrender to the United States authorities and appear before this Court to resolve the pending charges.”

While the alleged KickassTorrents operator would be open to a voluntary “surrender,” he probably wants several guarantees before that happens. TorrentFreak reached out to the defense team for more information, but they preferred not to comment on ongoing negotiations.

Previously, Megaupload’s Kim Dotcom made a similar offer in his criminal case, requesting living expenses and a fair trial. The US Government never took him up on this offer, it appears, as Dotcom still resides in New Zealand.

In Vaulin’s case, the defense previously submitted a motion to dismiss some or all of the charges in the indictment, and they hope a ruling on this will bring more clarity soon. With the requested status conference, both parties will at least be able to update the court on various procedural issues

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

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.


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": [
	"detail-type": [
		"AWS API Call via CloudTrail"
	"detail": {
		"eventSource": [
		"eventName": [

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.


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




Mira, tiny robot of joyful delight

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/mira-robot-alonso-martinez/

The staff of Pi Towers are currently melting into puddles while making ‘Aaaawwwwwww’ noises as Mira, the adorable little Pi-controlled robot made by Pixar 3D artist Alonso Martinez, steals their hearts.

Mira the robot playing peek-a-boo

If you want to get updates on Mira’s progress, sign up for the mailing list! http://eepurl.com/bteigD Mira is a desk companion that makes your life better one smile at a time. This project explores human robot interactivity and emotional intelligence. Currently Mira uses face tracking to interact with the users and loves playing the game “peek-a-boo”.

Introducing Mira

Honestly, I can’t type words – I am but a puddle! If I could type at all, I would only produce a stream of affectionate fragments. Imagine walking into a room full of kittens. What you would sound like is what I’d type.

No! I can do this. I’m a professional. I write for a living! I can…


Mira Alonso Martinez Raspberry Pi

Weebl & Bob meets South Park’s Ike Broflovski in an adorable 3D-printed bundle of ‘Aaawwwww’

Introducing Mira (I promise I can do this)

Right. I’ve had a nap and a drink. I’ve composed myself. I am up for this challenge. As long as I don’t look directly at her, I’ll be fine!

Here I go.

As one of the many über-talented 3D artists at Pixar, Alonso Martinez knows a thing or two about bringing adorable-looking characters to life on screen. However, his work left him wondering:

In movies you see really amazing things happening but you actually can’t interact with them – what would it be like if you could interact with characters?

So with the help of his friends Aaron Nathan and Vijay Sundaram, Alonso set out to bring the concept of animation to the physical world by building a “character” that reacts to her environment. His experiments with robotics started with Gertie, a ball-like robot reminiscent of his time spent animating bouncing balls when he was learning his trade. From there, he moved on to Mira.

Mira Alonso Martinez

Many, many of the views of this Tested YouTube video have come from me. So many.

Mira swivels to follow a person’s face, plays games such as peekaboo, shows surprise when you finger-shoot her, and giggles when you give her a kiss.

Mira’s inner workings

To get Mira to turn her head in three dimensions, Alonso took inspiration from the Microsoft Sidewinder Pro joystick he had as a kid. He purchased one on eBay, took it apart to understand how it works, and replicated its mechanism for Mira’s Raspberry Pi-powered innards.

Mira Alonso Martinez

Alonso used the smallest components he could find so that they would fit inside Mira’s tiny body.

Mira’s axis of 3D-printed parts moves via tiny Power HD DSM44 servos, while a camera and OpenCV handle face-tracking, and a single NeoPixel provides a range of colours to indicate her emotions. As for the blinking eyes? Two OLED screens boasting acrylic domes fit within the few millimeters between all the other moving parts.

More on Mira, including her history and how she works, can be found in this wonderful video released by Tested this week.

Pixar Artist’s 3D-Printed Animated Robots!

We’re gushing with grins and delight at the sight of these adorable animated robots created by artist Alonso Martinez. Sean chats with Alonso to learn how he designed and engineered his family of robots, using processes like 3D printing, mold-making, and silicone casting. They’re amazing!

You can also sign up for Alonso’s newsletter here to stay up-to-date about this little robot. Hopefully one of these newsletters will explain how to buy or build your own Mira, as I for one am desperate to see her adorable little face on my desk every day for the rest of my life.

The post Mira, tiny robot of joyful delight appeared first on Raspberry Pi.