🐛 Check to see if custom source implements fmt.Stringer when logging

[troy0820]

When using a custom source, the error when starting will fail because the fmt.Stringer interface is not implemented by the source. The builtin sources have already implanted this interface allow the below line to not fail:

log := c.LogConstructor(nil).WithValues("source", watch.String())

fatal error: concurrent map iteration and map write

Resolves #3057

[troy0820]

/test pull-controller-runtime-test

[dongjiang1989]

Great. Looks very elegant

[k8s-ci-robot]

@dongjiang1989: changing LGTM is restricted to collaborators

In response to this:

Great. Looks very elegant

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[alvaroaleman]

It is an interesting issue - How about rather then requiring the implementation of fmt.Stringer, we check if it is implemented and if yes use that, otherwise use the Type (i.E. fmt.Sprintf("%T", watch))? That way we avoid the breaking change

[alvaroaleman]

thanks!

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: a414c38213cf8ff7a9d5fe0e187d2c9bfbc50d2d

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alvaroaleman, dongjiang1989, troy0820

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[troy0820]

/cherry-pick release-0.19

[k8s-infra-cherrypick-robot]

@troy0820: #3068 failed to apply on top of branch "release-0.19":

Applying: add String() to source interface
Using index info to reconstruct a base tree...
M	pkg/internal/controller/controller.go
Falling back to patching base and 3-way merge...
Auto-merging pkg/internal/controller/controller.go
CONFLICT (content): Merge conflict in pkg/internal/controller/controller.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 add String() to source interface

In response to this:

/cherry-pick release-0.19

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.

[troy0820]

/cherry-pick release-0.20

[k8s-infra-cherrypick-robot]

@troy0820: new pull request created: #3077

In response to this:

/cherry-pick release-0.20

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.