Adding a package to contain common sidecar flags #202

DerekFrank · 2025-10-01T16:27:04Z

What type of PR is this?

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/kind api-change
/kind bug

/kind cleanup

/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

What this PR does / why we need it:

Following a discussion in the #csi channel of the k8s slack, folks generally support moving common sidecar flags into a shared package.

Example sidecar flags

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

k8s-ci-robot · 2025-10-01T16:27:07Z

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k8s-ci-robot · 2025-10-01T16:27:14Z

Hi @DerekFrank. Thanks for your PR.

I'm waiting for a kubernetes-csi 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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mauriciopoppe

Please add a link to the conversation thread in Slack in the PR description.

Thanks for considering the monorepo sidecar design as an example on how to extract the flags! Hey Ge, could you please check that these params match your analysis in https://docs.google.com/document/d/1AKqJeAlBL8PkH8D9zABCZ82Bk1N46EygKPvVh5p4-qU/edit? cc @ConnorJC3.

/cc @mowangdk
/ok-to-test

standardflags/flags.go

DerekFrank · 2025-10-02T17:18:29Z

config/config.go

+
+	logger := klog.Background()
+
+	// Prepare http endpoint for metrics + leader election healthz


I'm honestly not sure if we want to move this into this function as well, I did it because we need access to mux for le.PrepareHealthCheck(mux, leaderelection.DefaultHealthCheckTimeout) and as far as I can tell nothing else in the sidecar's main.go files reference the mux.

Yes, it looks odd here. Get the mux from the callers, as an argument.

DerekFrank · 2025-10-02T17:21:04Z

config/config.go

+	opts standardflags.SidecarConfiguration, 
+	run func(context.Context), 
+	driverName string, 
+	metricsManager metrics.CSIMetricsManager) {


Turned out to be more args then I'd ideally want. We could move the mux creation out of the function and thus remove metricsManager, but that'd be a 1:1 exchange of args. The other option is to create config locally but some of the sidecars modify their config right after creating it (setting config.ContentType = runtime.ContentTypeProtobuf for an example)

I think passing mux as a parameter would be better for now. Some other sidecars add more endpoints to it (e.g. the provisioner)

DerekFrank · 2025-10-02T17:22:09Z

features/features.go

+limitations under the License.
+*/
+
+package features


I don't know if this is standard across sidecars or if some sidecars have their own features. We only need ReleaseLeaderElectionOnExit but it seemed to make sense to move it all as long as its standard

Yes, each sidecar has its own feature gates and we need to keep them separated. RunWithLeaderElection needs to get ReleaseLeaderElectionOnExit as a parameter.

go.mod

jsafrane · 2025-10-03T08:42:38Z

features/features.go

+limitations under the License.
+*/
+
+package features


Yes, each sidecar has its own feature gates and we need to keep them separated. RunWithLeaderElection needs to get ReleaseLeaderElectionOnExit as a parameter.

jsafrane · 2025-10-03T08:47:14Z

config/config.go

+	opts standardflags.SidecarConfiguration, 
+	run func(context.Context), 
+	driverName string, 
+	metricsManager metrics.CSIMetricsManager) {


I think passing mux as a parameter would be better for now. Some other sidecars add more endpoints to it (e.g. the provisioner)

jsafrane · 2025-10-03T08:47:46Z

config/config.go

+
+	logger := klog.Background()
+
+	// Prepare http endpoint for metrics + leader election healthz


Yes, it looks odd here. Get the mux from the callers, as an argument.

config/config.go

DerekFrank · 2025-10-06T22:31:26Z

Made sidecar PRs as well for comparison:

The other sidecars don't have leader election, unless I missed one!

mowangdk · 2025-10-07T07:29:41Z

/lgtm

Thank you for your PR. This will also help the CSI Sidecar AIO project~

DerekFrank · 2025-10-07T17:56:58Z

@jsafrane Any other feedback?

Adding common flags to the standard flags package

e24562b

k8s-ci-robot added the kind/cleanup Categorizes issue or PR as related to cleaning up code, process, or technical debt. label Oct 1, 2025

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k8s-ci-robot requested review from andyzhangx and xing-yang October 1, 2025 16:27

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mauriciopoppe reviewed Oct 1, 2025

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k8s-ci-robot requested a review from mowangdk October 1, 2025 21:42

k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Oct 1, 2025

jsafrane reviewed Oct 2, 2025

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standardflags/flags.go Show resolved Hide resolved

DerekFrank force-pushed the common-flags branch from 9ed3658 to 43a8768 Compare October 2, 2025 17:15

k8s-ci-robot added size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. and removed size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Oct 2, 2025

DerekFrank commented Oct 2, 2025

View reviewed changes

go.mod Outdated Show resolved Hide resolved

refactor: Move leader election logic into csi-lib-utils and genericize

4814a37

DerekFrank force-pushed the common-flags branch from 43a8768 to 4814a37 Compare October 2, 2025 18:10

jsafrane reviewed Oct 3, 2025

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k8s-ci-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Oct 6, 2025

Merge branch 'master' into common-flags

00e101c

k8s-ci-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Oct 6, 2025

DerekFrank force-pushed the common-flags branch from f2fa3e4 to 888ae82 Compare October 6, 2025 21:14

DerekFrank mentioned this pull request Oct 6, 2025

refactor: use common sidecar flags functionality kubernetes-csi/external-attacher#684

Open

DerekFrank force-pushed the common-flags branch from 888ae82 to c772e19 Compare October 6, 2025 21:32

This was referenced Oct 6, 2025

Use central flags kubernetes-csi/external-provisioner#1421

Open

refactor: use common sidecar flags functionality kubernetes-csi/external-health-monitor#341

Open

Review feedback and using the new functionality in the sidecars

f9b84fa

DerekFrank force-pushed the common-flags branch from c772e19 to f9b84fa Compare October 6, 2025 21:57

This was referenced Oct 6, 2025

refactor: use common sidecar flags functionality kubernetes-csi/external-snapshotter#1336

Open

refactor: use common sidecar flags functionality kubernetes-csi/external-resizer#528

Open

k8s-ci-robot assigned mowangdk Oct 7, 2025

k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Oct 7, 2025


		logger := klog.Background()

		// Prepare http endpoint for metrics + leader election healthz

Adding a package to contain common sidecar flags #202

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Adding a package to contain common sidecar flags #202

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DerekFrank commented Oct 6, 2025

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DerekFrank commented Oct 1, 2025 •

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