fix: Error codes needs to be documented in Swagger

[William-Hill]

Fixes #576

Agent Summary

Excellent! Everything compiles and the changes are in place. Let me create a summary of what was implemented:

Summary

I have successfully implemented all three files according to the implementation plan. Here's what was written:

1. pkg/pipeline/service.go (Modified)

• Added imports: google.golang.org/grpc/codes and google.golang.org/grpc/status
• Standardized error handling across all service methods:
  • Validation errors (e.g., ErrNameMissing, ErrInvalidCharacters, ErrDescriptionOverLimit) → codes.InvalidArgument
  • Name already exists errors → codes.AlreadyExists
  • Instance not found errors → codes.NotFound
  • Connector/Processor ID not found errors → codes.NotFound
  • DLQ configuration validation errors → codes.InvalidArgument
  • Internal/database errors → codes.Internal
• Fixed variable naming conflict: Changed status variable to pipelineStatus in UpdateStatus and related helper methods to avoid shadowing the status package
• All error returns now use status.Errorf() with appropriate gRPC codes, allowing gRPC-Gateway to automatically translate them to the correct HTTP status codes

2. pkg/connector/service.go (Modified)

• Added imports: google.golang.org/grpc/codes and google.golang.org/grpc/status
• Standardized error handling across all service methods:
  • Validation errors (e.g., ErrNameMissing, ErrInvalidCharacters) → codes.InvalidArgument
  • Invalid plugin/pipeline ID/type → codes.InvalidArgument
  • Instance not found errors → codes.NotFound
  • Processor ID not found errors → codes.NotFound
  • Invalid connector state type → codes.InvalidArgument
  • Internal/database errors → codes.Internal
• All error returns now use status.Errorf() with appropriate gRPC codes
• Improved error messages with contextual information

3. proto/api/v1/api.proto (Modified)

• Added OpenAPI documentation for the UpdateDLQ RPC:
  • Documents HTTP 404 response with example code: 5 (NotFound)
  • Documents HTTP 400 response with example code: 3 (InvalidArgument) for DLQ configuration validation errors
• The StartPipeline RPC already had the appropriate error response documentation in place

Build Verification

✅ Build successful - go build ./... completes without errors

Key Benefits

1. HTTP 400 Bad Request for validation failures - Client-side validation errors now correctly return HTTP 400 instead of HTTP 500

2. Proper gRPC status codes - All errors are wrapped with appropriate gRPC codes that gRPC-Gateway translates to HTTP status codes:

   • InvalidArgument (3) → HTTP 400
   • NotFound (5) → HTTP 404
   • AlreadyExists (6) → HTTP 409
   • FailedPrecondition (9) → HTTP 400
   • Internal (13) → HTTP 500

3. OpenAPI documentation - The Swagger/OpenAPI spec now explicitly documents expected error responses with examples

4. Consistent error handling - Standardized approach across both services makes the codebase more maintainable

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Generated by conduit-agent-experiment (archivist: Gemini Flash, implementer: claude-haiku-4-5, 13 iterations).