Idea: Do not use version in dd-java-agent-<version>.jar

[tjuchniewicz]

My idea would be to skip version number in dd-java-agent-<version>.jar file used by this BP.

Describe the Enhancement

This would allow to overwrite BP_NATIVE_IMAGE_BUILD_ARGUMENTS without knowing DD agent version. Currently to use BP_NATIVE_IMAGE_BUILD_ARGUMENTS we have to repeat DD agent parameter including version number which is not known before build:

 <BP_NATIVE_IMAGE_BUILD_ARGUMENTS>
                    -O3
                    -J-Xmx14g
                    -J-javaagent:/layers/paketo-buildpacks_datadog/datadog-agent-java/dd-java-agent-${datadog-agent.version}.jar
</BP_NATIVE_IMAGE_BUILD_ARGUMENTS>

On every DD agent update we have to provide new value for datadog-agent.version in our CI.

Motivation

This solution would be a workaround for native-image BP: paketo-buildpacks/native-image#302

[dmikusa]

I don't think we can have the JAR file w/out a version number because we want the things on disk to be as clear as possible about what they are, but we could perhaps add a symlink where the symlink doesn't have a version number. That would give something consistent to point to.

[tjuchniewicz]

This would simplify our CI a lot. can we expect this will be implemented?

[dmikusa]

It's a reasonable thing to implement so eventually, yes, I think it'll get implemented. Being realistic, it's OSS software so there are no timelines or guarantees we can provide. If this is time-critical for you, you can submit a PR and we'll do our best to review that and get it merged.

I suspect that the symlink would get added here and then test coverage.

[tjuchniewicz]

@dmikusa Looks manageable for me. I will create PR next weeks. Thank you!