feat: Add support for attaching namespace metadata to Kubernetes SD

[dongjiang1989]

Description

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If it fixes an existing issue (bug or feature), use the following keyword:

Closes: #7799

Type of change

What type of changes does your code introduce to the Prometheus operator? Put an x in the box that apply.

• [ ] CHANGE (fix or feature that would cause existing functionality to not work as expected)
• [x] FEATURE (non-breaking change which adds functionality)
• [ ] BUGFIX (non-breaking change which fixes an issue)
• [ ] ENHANCEMENT (non-breaking change which improves existing functionality)
• [ ] NONE (if none of the other choices apply. Example, tooling, build system, CI, docs, etc.)

Verification

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Changelog entry

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Add support for attaching namespace metadata to Kubernetes SD

[dongjiang1989]

Thanks for the PR! Don't we have an existing issue with ScrapeConfig CRD and scrape classes? It seems that we don't merge the scrape class' attach metadata when generating the configuration from ScrapeConfig.

Thanks @simonpasquier Currently, there appears to be no issue, as the results have been uniformly processed via appendAttachMetadata.

[sebastienrospars]

Thanks for the work on this @dongjiang1989 ! 🙏 Is this PR still active? I’d love to use the namespace metadata feature and was wondering about its status.

[heliapb]

Thanks for the work on this @dongjiang1989 ! 🙏 Is this PR still active? I’d love to use the namespace metadata feature and was wondering about its status.

Hi @dongjiang1989 seems the pr has some conflicts if you could check? Thanks

[dongjiang1989]

@heliapb and @sebastienrospars I'll fix it soon

[dongjiang1989]

@simonpasquier @heliapb PTAL

[sebastienrospars]

Hello @heliapb, do you have some times to review this PR please ? Thanks by advance.