core: refactor lbaas util functions

[kayrus]

What this PR does / why we need it:

This is an experimental code refactoring using Claude AI as a development assistant. Each change was discussed and reviewed by me during the development process, it took about 6h in total. The refactoring reduces code duplication, fixes several bugs (missing metrics, potential panics, double observations), and optimizes API call patterns while preserving all existing functionality. All tests pass without modification. @zetaab @dulek @stephenfin I'd like you to review this as well. What do you think about such AI-assisted PRs?

Below is AI summary:

Key improvements

1. Reduced code duplication (-118 lines, ~15% reduction) - Extracted common patterns into reusable generic helpers:

   • executeAndWaitActive / executeExtractAndWaitActive - Centralizes metrics tracking, error handling, and LB wait logic
   • list / listWithUniqueResult - Standardizes pagination with early-exit optimization
   • getSingleResource - Consistent single-resource retrieval with metrics

2. Fixed bugs and inconsistencies:

   • Fixed missing metrics observation in 5 functions (GetPools, GetL7policies, GetL7Rules, GetListenersByLoadBalancerID, getOctaviaVersion extraction error)
   • Fixed double metrics observation bug in DeleteListener
   • Eliminated redundant check in GetPoolByName

3. Performance optimization:

   • GetPoolByListener now uses direct listener Get instead of listing all pools (major API call reduction)
   • listWithUniqueResult implements early-exit when multiple results detected on first page

4. Improved consistency:

   • Centralized NotFound error handling for all delete operations
   • Standardized error message format across all operations
   • Unified function documentation style (following AWS SDK Go conventions)
   • Consistent metrics tracking across all operations

5. Better organization:

   • Moved UpdatePool and DeletePool to correct section (Pool Operations, not Pool Member Operations)
   • Added clear section separators
   • Fixed function naming (GetMembersbyPool → GetPoolMembers)

Testing

• All existing unit tests pass without modification
• No functional changes - pure refactoring
• Verified with go test ./pkg/util/openstack/...

Files changed

• pkg/util/openstack/loadbalancer.go - Main refactoring

Special notes for reviewers:

Release note:

NONE

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[gouthampacha]

Hi @kayrus:

I don't have +2 powers here, so I'm just exercising my review judgement as a long time OpenStack maintainer and sharing my 0.02 cents of opinion.

I think the intent to address bugs is good, but, i'd like to suggest a different approach. You should break this down into multiple commits - get Claude to do it. I know we don't apply the same commit standards here as we do in OpenStack or core Kubernetes projects; but, for the sake of maintainability, seeing single-intent commits is preferred.

[stephenfin]

Hi @kayrus:

I don't have +2 powers here, so I'm just exercising my review judgement as a long time OpenStack maintainer and sharing my 0.02 cents of opinion.

I think the intent to address bugs is good, but, i'd like to suggest a different approach. You should break this down into multiple commits - get Claude to do it. I know we don't apply the same commit standards here as we do in OpenStack or core Kubernetes projects; but, for the sake of maintainability, seeing single-intent commits is preferred.

I asked for the same thing 😅 Must be an OpenStack thing...