Reduce number of layers for Beam container images

[Abacn]

Reduced Java container layer from 23->14; reduced Go container layer 17->4.

Mitigate artifact registry GET request http 429 error when frequently pull. The number of request is proportional to the number of container layers.

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[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request optimizes the Docker container images for both Java and Go SDKs by reducing the total number of layers. By consolidating build instructions and squashing base images, the changes aim to decrease the frequency of HTTP 429 errors encountered when pulling images from artifact registries, thereby improving deployment reliability.

Highlights

• Go Container Optimization: Squashed the distroless base image into a single layer using a multi-stage build with 'scratch' to reduce the total layer count from 17 to 4.
• Java Container Optimization: Consolidated multiple 'ADD' and 'COPY' instructions into fewer layers to reduce the total layer count from 23 to 14.
• Performance Impact: Reduced the number of container layers to mitigate HTTP 429 errors from artifact registries caused by excessive pull requests.

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[gemini-code-assist]

Code Review

This pull request optimizes the Dockerfiles for the Go and Java SDKs by squashing layers and consolidating file copy operations. Feedback identifies a critical syntax error in the Java Dockerfile where an inline comment within a multi-line COPY command would break the build. Additionally, it is recommended to use wildcards for optional jars to ensure compatibility across Java versions and to prefer COPY over ADD for local files to align with Docker best practices.

[gemini-code-assist]

The open-module-agent.jar is only present in Java 9+ builds. Using a specific filename in COPY will cause the build to fail if the file is missing (e.g., in Java 8 environments). Using a wildcard (e.g., target/open-module-agent.jar*) makes this file optional and ensures the build remains robust across different Java versions.

COPY target/open-module-agent.jar* target/beam-sdks-java-harness.jar /opt/apache/beam/jars/

[gemini-code-assist]

For local files and directories, COPY is preferred over ADD unless you specifically need the auto-extraction feature of ADD (e.g., for tarballs). Using COPY is more explicit and follows Docker best practices, consistent with other changes in this pull request.

COPY target/third_party_licenses /opt/apache/beam/third_party_licenses/

[gemini-code-assist]

Use COPY instead of ADD for local files when no extraction is required. This is a Docker best practice and maintains consistency with the improvements made in the Java Dockerfile.

COPY target/${TARGETOS}_${TARGETARCH}/boot /opt/apache/beam/

[Abacn]

R: @shunping

[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control. If you'd like to restart, comment assign set of reviewers

[shunping]

LGTM