Add reconciling logic for creating cronjobs whenever a new cleanup policy is created

[NikhilSharmaWe]

Signed-off-by: Nikhil Sharma nikhilsharma230303@gmail.com

Explanation

This PR adds reconciling logic for creating CronJob whenever a new cleanup policy is created.

[codecov]

Codecov Report

Merging #5385 (fbad540) into main (fa88f4a) will not change coverage.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##             main    #5385   +/-   ##
=======================================
  Coverage   36.42%   36.42%           
=======================================
  Files         172      172           
  Lines       19087    19087           
=======================================
  Hits         6952     6952           
  Misses      11340    11340           
  Partials      795      795           

Impacted Files	Coverage Δ
api/kyverno/v1alpha1/cleanup_policy_types.go	48.50% <50.00%> (ø)

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[eddycharly]

@NikhilSharmaWe we need to reconcile observed state with desired state, it means we can't just create cronjobs, the schedule could change for example.

[eddycharly]

@NikhilSharmaWe I think code can be factorised, I will push a commit if it's ok.

[eddycharly]

@NikhilSharmaWe I pushed the changes, I took the opportunity to add generic support to enqueue funcs in controller utils.

[realshuting]

@NikhilSharmaWe - can you clarify how the namespace is selected to create the cronjob? For clustercleanuppolicy and cleanuppolicy respectively?

[NikhilSharmaWe]

For CleanupPolicy, the cronjob namespace is the same as the policy's namespace.
For ClusterCleanupPolicy, the cronjob namespace will be the Kyverno namespace.

[realshuting]

Thanks Nikhil, that's what I understood.

Not sure if it makes sense to create cronjobs for all policies in the kyverno namespace. It could be confusing to use different namespaces for cleanup policies. This is easy to change, we can update it in the follow-up PRs if needed.

[eddycharly]

Cross namespace owner references are not allowed.

[eddycharly]

In case of a namespaced policy the cronjob has to live in the same namespace.

[realshuting]

Looks good overall, have a question about the cronjob's namespace. See comments:

[eddycharly]

Let's try to get this in 🤞