Optimize go build caching in `release-binary` make target

[Dhairya-Arora01]

The release-binary Makefile target currently uses /tmp/ as the GOCACHE directory inside the Docker container, which means the build cache is discarded after every run. This results in slower builds since Go has to recompile everything from scratch each time.

The make target release-binaries build the clusterctl binary for each architecture by calling the release-binary target. Therefore, the same go packages are installed each and every time and recompilation from scratch occurs every time which is bit inefficient.

Changes proposed:

• Set GOCACHE to /go/build-cache/ instead of /tmp/
• Mount the host's GOMODCACHE into the container at /go/pkg/mod to reuse downloaded modules.
• Mount the host's GOCACHE into the container at /go/build-cache to persist the build cache across runs.

These volume mounts allow the Docker build to leverage caches from the host machine, significantly speeding up incremental builds.

[fabriziopandini]

/triage accepted
/help

[k8s-ci-robot]

@fabriziopandini:
This request has been marked as needing help from a contributor.

Guidelines

Please ensure that the issue body includes answers to the following questions:

• Why are we solving this issue?
• To address this issue, are there any code changes? If there are code changes, what needs to be done in the code and what places can the assignee treat as reference points?
• How can the assignee reach out to you for help?

For more details on the requirements of such an issue, please see here and ensure that they are met.

If this request no longer meets these requirements, the label can be removed
by commenting with the /remove-help command.

Details

In response to this:

/triage accepted
/help

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[Dhairya-Arora01]

/assign