WIP: Add support for using CSIVolumeSource as workspaces

[vdemeester]

Changes

This adds support for using kubernetes CSI
volumes (https://kubernetes.io/docs/concepts/storage/volumes/#csi) as
workspaces.

This opens a lot of possibility as it would enable users to use
alternative volumes for their workspace. An example is the Secrets
Store CSI
Driver (https://secrets-store-csi-driver.sigs.k8s.io/introduction.html)
to use Hashicorp Vault.

It could also open doors for Tekton to ship its own CSI driver to
share data between tasks without the need of a PVC.

Signed-off-by: Vincent Demeester [email protected]

/kind feature
/cc @tektoncd/core-maintainers @imjasonh @abayer

Closes #4446

This still needs

• Figure out if I need to write a TEP or not 🙏🏼
• Tests
• Docs

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Docs included if any changes are user facing
• Tests included if any functionality added or changed
• Follows the commit message standard
• Meets the Tekton contributor standards (including
  functionality, content, code)
• Release notes block below has been filled in
  (if there are no user facing changes, use release note "NONE")

Release Notes

Add support to use any CSI volume driver as a workspace

[tekton-robot]

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[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/apis/pipeline/v1beta1/workspace_validation.go	100.0%	96.4%	-3.6

[dibyom]

Thank you @vdemeester

Re: Figure out if I need to write a TEP or not 🙏🏼

My $0.02 - The new experimental TEP process says we should start with a issue or a PR labelled [design-idea] and that "if the change is agreed to be small enough that a doc is not warranted and PRs can be opened and merged directly, " - IMO this is a good example of an instance where we can skip the design doc and merge :)

[imjasonh]

My $0.02 - The new experimental TEP process says we should start with a issue or a PR labelled [design-idea] and that "if the change is agreed to be small enough that a doc is not warranted and PRs can be opened and merged directly, " - IMO this is a good example of an instance where we can skip the design doc and merge :)

Yes! This is exactly the kind of change I'd like for us to at least consider as not needing a TEP. FWIW I think it's possible, since this is both a relatively small and relatively well understood addition to the API. The only real gap I see is a testing plan, but I believe in @vdemeester to come up with something for that.

[vdemeester]

Yes! This is exactly the kind of change I'd like for us to at least consider as not needing a TEP. FWIW I think it's possible, since this is both a relatively small and relatively well understood addition to the API. The only real gap I see is a testing plan, but I believe in @vdemeester to come up with something for that.

Yes, that's why it's a WIP right now 😝

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/apis/pipeline/v1beta1/workspace_validation.go	100.0%	96.4%	-3.6

[tekton-robot]

@vdemeester: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
pull-tekton-pipeline-build-tests	3443590	link	/test pull-tekton-pipeline-build-tests

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[vdemeester]

Closing in favor of #5030 😉