AWS Lambda Java Base Images

This project provides the missing AWS Lambda base image for Java 17, 18, 19, 20, and 21. The base images are publicly available in the ECR Public Gallery. You should be able to use them directly in your builds. I use these images in production for personal and commercial projects today, but per the license, there is no warranty, and YMMV.

Approach

This project uses the following process to create new Lambda base images:

1. Define a Java maven POM that includes all the Java Lambda support libraries as provided scope. This roundabout approach is used to coax @dependabot into flagging new versions as they are published.
2. Also teach maven to collect these dependencies and build the appropriate docker images using a Dockerfile and the excellent fabric8io/docker-maven-plugin.
3. Use GitHub Actions to perform CI/CD and release new images to the ECR Public Gallery.

Example Lambda Function

You can find an example Lambda function using these base images at aleph0io/example-java-lambda-function. It's just like building any container lambda function. For ease of use, find the Dockerfile below. Note the FROM image. Java versions 17-20 are also supported.

FROM public.ecr.aws/aleph0io/java/lambda:21-al2

COPY target/hello-lambda.jar "${LAMBDA_TASK_ROOT}/lib/"

CMD [ "com.sigpwned.lambda.hello.HelloLambda::handleRequest" ]

Testing Lambda Functions Locally

The Lambda RIE is not currently built into these lambda base images, so to test your lambda function implementations locally, you will need to use the standalone RIE server.

Known Issues and Future Plans

• This image is in no way optimized for cold start time, size, etc. PRs welcome!
• Java 17, 18, 19, 20, and 21 are all supported.
• For now, only x86_64 is supported. I hope to publish multiarch builds including arm64 soon.
• Official base images for Java 17 have been released to lambda/java. Java 17 users should strongly consider moving to the officially-supported base images. This project will continue to release updates for Java 17 on an ongoing basis for those who prefer not to move.
• This project will continue to support non-LTS Java versions that will never receive an officially-supported AWS Lambda base image.

More Information

You can find writeups of the Java 17, 18, 19, 20, and 21 on my blog.

Acknowledgements

Many thanks to @rieckpil for his outstanding writeup of custom Lambda runtimes. That tutorial was the foundation and basis for this build. Cheers!

Also, thank you to @msailes for the example Java 17 Lambda layer. This prior art was also critically important to understanding how best to integrate a new Java version into Lambda.

Managed by @sigpwned.