kratos-service-layer

name: kratos-service-layer description: Generates gRPC/HTTP service handlers for go-kratos microservices. Creates service structs, handler methods, and integrates with protobuf definitions. Use when implementing RPC handlers, adding API endpoints, creating dual transport (HTTP/gRPC) handlers, or connecting transport layer to business logic in kratos services.

<essential_principles>

How Kratos Service Layer Works

Service Layer Role

Connects transport (gRPC/HTTP) to business logic:

Responsibilities:

• Handle gRPC/HTTP requests
• Map proto DTOs to business models (via mapper)
• Call use case methods
• Map results back to proto responses
• Convert business errors to gRPC status codes

Service Struct Pattern

type {Entity}Service struct {
	pb.Unimplemented{Entity}ServiceServer  // Embed unimplemented server
	uc domain.{Entity}UseCase             // Use case dependency (from domain package)
}

Import: import "{service}/internal/biz/domain"

Handler Method Pattern

func (s *{Entity}Service) Create{Entity}(ctx context.Context, in *pb.Request) (*pb.Response, error) {
	// 1. Map request to business model
	entity := {Entity}FromRequest(in)

	// 2. Call use case
	result, err := s.uc.Create{Entity}(ctx, entity)
	if err != nil {
		return nil, toServiceError(err)  // Map business error to gRPC error
	}

	// 3. Map result to response
	return &pb.Response{Entity: toProto{Entity}(result)}, nil
}

</essential_principles>

1. Create service handlers for new entity
2. Add handler methods to existing service
3. View handler patterns and examples

Wait for response before proceeding. </intake>

After reading the workflow, follow it exactly. </routing>

<reference_index> Core: handler-pattern.md, service-structure.md, error-mapping.md Mappers: mapper-conventions.md </reference_index>

<workflows_index>

<success_criteria> Service layer code is correct when:

• Service struct embeds Unimplemented{Entity}ServiceServer
• Constructor added to service.ProviderSet
• Handlers map DTOs via mapper functions
• Errors converted to gRPC status codes
• All methods have godoc comments
• User reminded to run make generate </success_criteria>