refactor: addLoadBalancer

[ianchen0119]

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[ianchen0119]

This pull request includes multiple changes to the loadbalancer package in the pkg/agent/manager/loadbalancer/loadbalancer.go file and introduces new constants in the pkg/api/lb.go file. These changes primarily focus on error handling improvements, annotation checks, and code simplification.

Error Handling Improvements:

• Replaced standard fmt.Errorf with github.com/pkg/errors for better error wrapping and stack trace support. (pkg/agent/manager/loadbalancer/loadbalancer.go) [1] [2] [3] [4] [5] [6] [7]
• Added error wrapping to provide more context in error messages. (pkg/agent/manager/loadbalancer/loadbalancer.go) [1] [2] [3] [4] [5]

Annotation Checks:

• Simplified and corrected the logic for checking lbAddressAnnotation values. (pkg/agent/manager/loadbalancer/loadbalancer.go)
• Refactored endPointSelAnnotation checks to use a switch statement for better readability and maintainability. (pkg/agent/manager/loadbalancer/loadbalancer.go)

Code Simplification:

• Removed redundant klog.Errorf calls before returning errors. (pkg/agent/manager/loadbalancer/loadbalancer.go) [1] [2]
• Replaced hardcoded values with new constants defined in pkg/api/lb.go, improving code readability and maintainability. (pkg/agent/manager/loadbalancer/loadbalancer.go) [1] [2]

New Constants:

• Added new constants for load balancer modes in pkg/api/lb.go to replace magic numbers and string literals. (pkg/api/lb.go)

Import Adjustments:

• Added github.com/pkg/errors to the import list and removed the unused errors package. (pkg/agent/manager/loadbalancer/loadbalancer.go) [1] [2]

[ianchen0119]

Hi @TrekkieCoder

I refactored a part of the implementation for better readability.
Please help to review it when you feel free.

Tks!