--- name: go-grpc-2af2bd2a02e0 description: High-performance RPC framework with Protocol Buffers. metadata: labels: [golang, grpc, protobuf, rpc] triggers: files: ['**/*.proto', '**/*_grpc.pb.go'] keywords: [grpc, proto, RegisterServer, NewClient] --- # Go gRPC Standards ## Proto Definition ```protobuf // proto/user.proto syntax = "proto3"; package user; option go_package = "myapp/gen/user"; service UserService { rpc GetUser (GetUserRequest) returns (User); rpc ListUsers (ListUsersRequest) returns (stream User); rpc CreateUsers (stream CreateUserRequest) returns (CreateUsersResponse); rpc Chat (stream Message) returns (stream Message); } message User { int64 id = 1; string name = 2; string email = 3; } message GetUserRequest { int64 id = 1; } message ListUsersRequest { int32 page_size = 1; string page_token = 2; } ``` ## Code Generation ```bash # Install go install google.golang.org/protobuf/cmd/protoc-gen-go@latest go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest # Generate protoc --go_out=. --go-grpc_out=. proto/user.proto ``` ## Server Implementation ```go type userServer struct { pb.UnimplementedUserServiceServer db *sql.DB } func (s *userServer) GetUser(ctx context.Context, req *pb.GetUserRequest) (*pb.User, error) { user, err := s.db.FindUser(ctx, req.Id) if err != nil { return nil, status.Errorf(codes.NotFound, "user not found: %v", err) } return &pb.User{ Id: user.ID, Name: user.Name, Email: user.Email, }, nil } func main() { lis, _ := net.Listen("tcp", ":50051") s := grpc.NewServer() pb.RegisterUserServiceServer(s, &userServer{db: db}) s.Serve(lis) } ``` ## Client ```go func main() { conn, err := grpc.Dial("localhost:50051", grpc.WithTransportCredentials(insecure.NewCredentials())) if err != nil { log.Fatal(err) } defer conn.Close() client := pb.NewUserServiceClient(conn) ctx, cancel := context.WithTimeout(context.Background(), time.Second) defer cancel() user, err := client.GetUser(ctx, &pb.GetUserRequest{Id: 1}) if err != nil { log.Fatal(err) } fmt.Printf("User: %v\n", user) } ``` ## Streaming ```go // Server streaming func (s *userServer) ListUsers(req *pb.ListUsersRequest, stream pb.UserService_ListUsersServer) error { users, _ := s.db.ListUsers(req.PageSize) for _, user := range users { if err := stream.Send(user); err != nil { return err } } return nil } // Client streaming func (s *userServer) CreateUsers(stream pb.UserService_CreateUsersServer) error { var count int32 for { req, err := stream.Recv() if err == io.EOF { return stream.SendAndClose(&pb.CreateUsersResponse{Count: count}) } if err != nil { return err } s.db.CreateUser(req) count++ } } // Bidirectional streaming func (s *userServer) Chat(stream pb.UserService_ChatServer) error { for { msg, err := stream.Recv() if err == io.EOF { return nil } if err != nil { return err } reply := &pb.Message{Text: "Echo: " + msg.Text} if err := stream.Send(reply); err != nil { return err } } } ``` ## Interceptors ```go // Unary interceptor func loggingInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { start := time.Now() resp, err := handler(ctx, req) log.Printf("Method: %s, Duration: %s, Error: %v", info.FullMethod, time.Since(start), err) return resp, err } // Auth interceptor func authInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { md, ok := metadata.FromIncomingContext(ctx) if !ok { return nil, status.Error(codes.Unauthenticated, "no metadata") } tokens := md.Get("authorization") if len(tokens) == 0 { return nil, status.Error(codes.Unauthenticated, "no token") } // Validate token... return handler(ctx, req) } // Apply interceptors s := grpc.NewServer( grpc.ChainUnaryInterceptor(loggingInterceptor, authInterceptor), grpc.ChainStreamInterceptor(streamLoggingInterceptor), ) ``` ## Error Handling ```go import ( "google.golang.org/grpc/codes" "google.golang.org/grpc/status" ) func (s *userServer) GetUser(ctx context.Context, req *pb.GetUserRequest) (*pb.User, error) { if req.Id <= 0 { return nil, status.Error(codes.InvalidArgument, "invalid user id") } user, err := s.db.FindUser(ctx, req.Id) if err == sql.ErrNoRows { return nil, status.Error(codes.NotFound, "user not found") } if err != nil { return nil, status.Error(codes.Internal, "database error") } return user, nil } // Client error handling user, err := client.GetUser(ctx, req) if err != nil { st, ok := status.FromError(err) if ok { switch st.Code() { case codes.NotFound: // Handle not found case codes.InvalidArgument: // Handle invalid input } } } ``` ## Best Practices 1. **Proto first**: Design API in proto files 2. **Deadlines**: Always set context timeouts 3. **Errors**: Use gRPC status codes correctly 4. **Streaming**: For large data or real-time 5. **Interceptors**: Logging, auth, metrics --- Source attribution: ngxtm Original project: https://github.com/ngxtm/devkit/blob/9439f27ce3fa7fe53ff9278a1ee9a44bffa70eba/rules/golang/grpc/SKILL.md License: MIT License information: https://opensource.org/license/mit Original upstream instructions; downloaded from Mega AI Hub. ## Upstream license notice MIT License Copyright (c) 2024 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Mega AI Hub resource metadata Creator / publisher: ngxtm Original project: https://github.com/ngxtm/devkit/blob/9439f27ce3fa7fe53ff9278a1ee9a44bffa70eba/rules/golang/grpc/SKILL.md Attribution basis: Source repository record Fields of work: Development & Engineering Roles: Backend Developer, Data Engineer, ML / AI Engineer Specialties: Backend Tools: Golang, Grpc, Protobuf Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: 144d4fbb003ac164bf11a96ec8d99731b38d65ca62e1773ff805102f66bcf48d