feat(backend): add subPath support for PVC mounts. Fixes #11832

[vmridul]

Summary
Added support for PVC subPath mounting in Kubeflow Pipelines by passing an optional sub_path parameter to the PVC mount function, enabling users to mount a specific folder within a PVC.

Key Implementation Details

1. Protobuf Definition:
   Added sub_path field to PvcMount message in kubernetes_executor_config.proto
   Regenerated Python and Go protobuf code to support the new field

2. Python SDK Enhancement:
   Updated mount_pvc() function in kfp/kubernetes/volume.py to accept optional sub_path parameter
   Maintains backward compatibility with default None value
   Passes sub_path to protobuf message creation

3. Backend Integration:
   Modified makeVolumeMountPatch() in backend/src/v2/driver/k8s.go to read sub_path from protobuf
   Passes SubPath to Kubernetes VolumeMount struct
   Leverages native Kubernetes subPath support

4. Test Coverage:
   Added Python unit test: test_mount_pvc_with_subpath
   Added Go unit test: test case for pvc_with_subPath
   All existing tests continue to pass

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[google-oss-prow]

Hi @vmridul. Thanks for your PR.

I'm waiting for a kubeflow member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[hbelmiro]

@vmridul There are several changes in this PR that seem unrelated to the description. For example, GitHub workflows and a downgrade of envoyproxy/envoy in a Dockerfile.

[vmridul]

Apologies for the confusion, and thanks for flagging this. I’m new to contributing here, and those changes were accidentally picked up during my local workflow, they’re not intentional and not related to the PVC subPath work.

I’ll correct the PR so it only contains the relevant changes.

[google-oss-prow]

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[droctothorpe]

/ok-to-test

[hbelmiro]

/ok-to-test

[hbelmiro]

@vmridul can you please link the PR to the issues and rebase?

[hbelmiro]

@vmridul nevermind. Another PR that fixes the same issue was merged.
Closing in favor of #12595.
/close

[google-oss-prow]

@hbelmiro: Closed this PR.

Details

In response to this:

@vmridul nevermind. Another PR that fixes the same issue was merged.
Closing in favor of #12595.
/close

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