kratos-service-layer

Development

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.

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Source SKILL.md: https://github.com/majiayu000/claude-skill-registry/blob/HEAD/skills/data/kratos-service-layer/SKILL.md

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<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>

Create service handlers for new entity
Add handler methods to existing service
View handler patterns and examples

Wait for response before proceeding.

After reading the workflow, follow it exactly.

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

<workflows_index>

Workflow	Purpose
create-service.md	Generate service handlers and mappers
add-handlers.md	Add methods to existing service
view-examples.md	Show patterns
</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>