philippgille/alexa-java-builder repository overview

⁠Alexa Java Builder Docker Image

This repository contains the necessary files for the Alexa Java Builder Docker image.

This image enables you to build a JAR for an Alexa skill AWS Lambda function without having to install Maven and also all basic Alexa Skills Kit Java SDK and samples dependencies are already included in the image, so that they don't have to be downloaded every time you build with a Maven Docker container.

Note though that any dependencies declared in your pom.xml that are not part of the Alexa Skills Kit Java SDK or its samples get downloaded with every build when you use this image in a docker run command. Create your own image based on this one to include your specific dependencies in an image as well.

⁠Supported tags and respective Dockerfile links

• alpine, latest (alpine/Dockerfile)⁠
• debian (Dockerfile)⁠

⁠Usage

docker run --rm -v /path/to/pom-dir:/usr/src/mymaven philippgille/alexa-java-builder
ls /path/to/pom-dir/target/
example-skill-1.0.jar  example-skill-1.0-jar-with-dependencies.jar  archive-tmp  classes  generated-sources  maven-archiver  maven-status

⁠Details

• You could achieve the same end result - the packaged JAR - with the command:
  • mvn assembly:assembly -DdescriptorId=jar-with-dependencies
• But what if you don't have Maven installed, or an incompatible version? You could use Docker and run:
  • docker run --rm -v /path/to/pom-dir:/usr/src/mymaven -w /usr/src/mymaven maven:3.3-jdk-8-alpine mvn assembly:assembly -DdescriptorId=jar-with-dependencies
• But that downloads all the dependencies every time you build the JAR. So you could run:
  • docker run --rm -v /path/to/pom-dir:/usr/src/mymaven -v "/path/to/maven-repo":/root/.m2 -w /usr/src/mymaven maven:3.3-jdk-8-alpine mvn assembly:assembly -DdescriptorId=jar-with-dependencies
• But what if you don't want any downloaded dependencies on your local machine? What if you want your build machine / environment to be completely stateless?
  • Well, then you create a Docker image that already contains all the dependencies. Which is exactly what this repository contains. Including default values for working directory and launch command.

⁠Details about the Dockerfile

• Why is assembly:assembly used instead of dependency:resolve?
  • When using an image that used dependency:resolve to create an image layer containing downloaded dependencies to build an Alexa skill jar with dependencies with Maven later, many more files would have to get downloaded. Just try out yourself.
• Why is -s /usr/share/maven/ref/settings-docker.xml used when creating the image layer?
  • By default the Maven Docker image uses /root/.m2 as repository location. But that's configured as volume, so all data would be lost after build time. See the README of the official Maven docker container: Link⁠
• Why is -s /usr/share/maven/ref/settings-docker.xml needed in the CMD line?
  • Otherwise /root/.m2 would be used as repository location. But that's configured as volume, so it would be empty when a container gets started from this image. See the README of the official Maven Docker container: Link⁠