[PR] Add a warning if patch doesn't succeed

[kopf-archiver]

A pull request by michaelnarodovitch at 2020-04-01 12:30:01+00:00
Original URL: zalando-incubator/kopf#339
 

What do these changes do?

The situation

• kopf submits a merge-patch+json patch
• kubernetes API doesn't apply the merge-patch+json patch but responds 200 OK

leads to bugs and confusion, when testing operators.

With this change, kopf will check, if the merge-patch+json patch was merged and be verbose, if the patch was not exactly successful.

Description

Before: When a patch wasn't merged, then kopf didn't report anything.

After: When a patch wasn't merged, then kopf will report if ran in --verbose mode.

This will help users to debug their operators. Especially, when they use OpenAPI schemas in their CRDs.

Not sure if the check is in the right place and the logger is setup appropriately.

No risky changes.

Issues/PRs

If a patch is not merged, then it is usually because of a schema mismatch of the CRD. For this reason it was discussed to move the internal kopf status to the annotations. #308 #321

Type of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• The code addresses only the mentioned problem, and this problem only
• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you provide code modification, please add yourself to CONTRIBUTORS.txt

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Commented by michaelnarodovitch at 2020-04-03 14:26:15+00:00
 

Thx for all the comments and suggestions. Had to add quite a bit of code. I think quality is OK and changes are safe.

Missing is integration tests with the Kubernetes API responses, and especially integration tests with the status_patch merging. What I did was based of an educated guess from reviewing https://github.com/kubernetes/apiextensions-apiserver. If we wanted to be 100% safe, we would also have to test the PATCH API of the canonical Kubernetes objects.

[nolar]

Reimplemented in #527 based on the original solution in this PR, but with a different approach to comparison (via diffs instead of own implementation of patching, which can mismatch with K8s's implementation).