gapic-generator-java feat: bake gapic-generator-java into the hermetic build docker image

Built on top of https://github.com/googleapis/sdk-platform-java/pull/3045 (needs to be merged first)

Jul 24 '24 20:07 diegomarquezp

@blakeli0 I removed gapic_generator_version altogether. We now only rely on DOCKER_GAPIC_GENERATOR_LOCATION that will point to the jar we need and not care about the location.

This however brought many changes in the test folder but most of them are simple.

Aug 09 '24 02:08 diegomarquezp

@JoeWang1127 @blakeli0 the integration tests now can't be locked to a specific generator version, so we will constantly need to update them.

A few ideas:

Add an --update flag to the integration tests
Keep a locked-in jar in the test resources folder and override the generator version
Add test-only logic in the Dockerfile (e.g. figure out if the jar should be downloaded or mvn install-ed by converting this version into an overridable ARG)

Aug 30 '24 01:08 diegomarquezp

spring downstream check failing because the release job still doesn't publish the maven artifacts

https://github.com/GoogleCloudPlatform/spring-cloud-gcp/pull/3138#issuecomment-2318598130

cc: @mpeddada1

Aug 30 '24 02:08 diegomarquezp

the integration tests now can't be locked to a specific generator version, so we will constantly need to update them

I think it's fine to test the snapshot version of the generator.

Ideally, running the generation can produce the same file even if the generator updates, though some changes in the generator can produce different code and we can update the golden file accordingly, just like the showcase integration test.

At this point, I think it's fine. However, we need to improvement the integration test:

Use golden file rather than branch in google-cloud-java
Provide an easy way to update the golden file

@blakeli0 WDYT?

Aug 30 '24 13:08 JoeWang1127

From discussion with @blakeli0 and @JoeWang1127, we can lock in a specific version string of the generator, download it in our integration test and then override the well-known location via volumes

Aug 30 '24 18:08 diegomarquezp

@JoeWang1127 I modified the integration test to lock-in a specific generator jar downloaded via mvn. PTAL when you have a chance :)

Aug 31 '24 00:08 diegomarquezp