chore(store): Added RESTConfig() to ClientGenerator

[ivankatliarchuk]

What does it do ?

Currently rest config is created multiple times (singleton pattern is not enforced), hence multiple sources do not respect api rate limits and etc.

I have found a bug in current implementation. Bug behavior on subsequent calls (no error due to sync.Once pattern). Errors are only returned on the first call due to sync.Once behavior. I've added tests and TODO. Will address this bug in follow-up pull-request + will add more unit tests. This bug is not critical, and external-dns works, so could be done in follow up, no rush here.

Motivation

• Singleton Pattern - REST config created once, reused across all clients.
• Respects UpdateEvents - Automatically respects event-driven sources
• Consistent Configuration - All clients use the same instrumented REST config
• Future-Ready - CRD source (when migrated) can use p.RESTConfig() refactor(crd): replace raw REST client with controller-runtime client #6176
• Single point to mock REST config creation

More

• Yes, this PR title follows Conventional Commits
• Yes, I added unit tests
• Yes, I updated end user documentation accordingly

┌──────────┬───────┐
│ Category │ Lines │
├──────────┼───────┤
│ Non-test │ +68   │
├──────────┼───────┤
│ Test     │ +174  │
├──────────┼───────┤
│ Ratio    │ 1:2.5│
└──────────┴───────┘

[coveralls]

Pull Request Test Coverage Report for Build 22218776324

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 113 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.06%) to 79.214%

---

Files with Coverage Reduction	New Missed Lines	%
openshift_route.go	1	83.97%
crypto.go	15	67.9%
store.go	97	52.25%

Totals
Change from base Build 21559764040:	0.06%
Covered Lines:	16055
Relevant Lines:	20268

---

💛 - Coveralls

[vflaux]

Aren't TestSingletonClientGenerator_RESTConfig_Singleton and TestSingletonClientGenerator_RESTConfig_SharedAcrossClients identical?

[ivankatliarchuk]

Removed TestSingletonClientGenerator_RESTConfig_Singleton

[vflaux]

/lgtm

[ivankatliarchuk]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ivankatliarchuk

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