Go и gRPC: высокопроизводительные API

1syntax = "proto3";
2
3package user;
4
5option go_package = "github.com/user/proto;userpb";
6
7service UserService {
8    rpc GetUser(GetUserRequest) returns (User);
9    rpc ListUsers(ListUsersRequest) returns (stream User);
10    rpc CreateUser(CreateUserRequest) returns (User);
11}
12
13message User {
14    int32 id = 1;
15    string name = 2;
16    string email = 3;
17}
18
19message GetUserRequest {
20    int32 id = 1;
21}
22
23message ListUsersRequest {
24    int32 page = 1;
25    int32 per_page = 2;
26}
27
28message CreateUserRequest {
29    string name = 1;
30    string email = 2;
31}

1# Установка protoc
2brew install protobuf
3
4# Установка плагинов
5go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
6go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
7
8# Генерация
9protoc --go_out=. --go-grpc_out=. user.proto

1package main
2
3import (
4    "context"
5    "log"
6    "net"
7
8    "google.golang.org/grpc"
9    "github.com/user/proto/userpb"
10)
11
12type server struct {
13    userpb.UnimplementedUserServiceServer
14}
15
16func (s *server) GetUser(ctx context.Context, req *userpb.GetUserRequest) (*userpb.User, error) {
17    return &userpb.User{
18        Id:    req.Id,
19        Name:  "Alice",
20        Email: "alice@example.com",
21    }, nil
22}
23
24func (s *server) ListUsers(req *userpb.ListUsersRequest, stream userpb.UserService_ListUsersServer) error {
25    for i := int32(0); i < 10; i++ {
26        if err := stream.Send(&userpb.User{
27            Id:    i,
28            Name:  "User",
29            Email: "user@example.com",
30        }); err != nil {
31            return err
32        }
33    }
34    return nil
35}
36
37func main() {
38    lis, _ := net.Listen("tcp", ":50051")
39    grpcServer := grpc.NewServer()
40    userpb.RegisterUserServiceServer(grpcServer, &server{})
41
42    log.Println("gRPC server on :50051")
43    grpcServer.Serve(lis)
44}

1package main
2
3import (
4    "context"
5    "log"
6
7    "google.golang.org/grpc"
8    "google.golang.org/grpc/credentials/insecure"
9    "github.com/user/proto/userpb"
10)
11
12func main() {
13    conn, _ := grpc.Dial("localhost:50051",
14        grpc.WithTransportCredentials(insecure.NewCredentials()))
15    defer conn.Close()
16
17    client := userpb.NewUserServiceClient(conn)
18
19    // Unary RPC
20    user, err := client.GetUser(context.Background(), &userpb.GetUserRequest{Id: 1})
21    if err != nil {
22        log.Fatal(err)
23    }
24    log.Printf("User: %v", user)
25
26    // Server streaming
27    stream, _ := client.ListUsers(context.Background(), &userpb.ListUsersRequest{})
28    for {
29        user, err := stream.Recv()
30        if err != nil {
31            break
32        }
33        log.Printf("User: %v", user)
34    }
35}

1func loggingInterceptor(
2    ctx context.Context,
3    req interface{},
4    info *grpc.UnaryServerInfo,
5    handler grpc.UnaryHandler,
6) (interface{}, error) {
7    log.Printf("gRPC call: %s", info.FullMethod)
8    start := time.Now()
9
10    resp, err := handler(ctx, req)
11
12    log.Printf("gRPC call %s completed in %v", info.FullMethod, time.Since(start))
13    return resp, err
14}
15
16func main() {
17    grpcServer := grpc.NewServer(
18        grpc.UnaryInterceptor(loggingInterceptor),
19    )
20}

1func authInterceptor(
2    ctx context.Context,
3    req interface{},
4    info *grpc.UnaryServerInfo,
5    handler grpc.UnaryHandler,
6) (interface{}, error) {
7    // Извлечение токена из metadata
8    md, ok := metadata.FromIncomingContext(ctx)
9    if !ok {
10        return nil, status.Error(codes.Unauthenticated, "missing metadata")
11    }
12
13    tokens := md.Get("authorization")
14    if len(tokens) == 0 {
15        return nil, status.Error(codes.Unauthenticated, "missing token")
16    }
17
18    // Проверка токена
19    userID, err := validateToken(tokens[0])
20    if err != nil {
21        return nil, status.Error(codes.Unauthenticated, "invalid token")
22    }
23
24    // Добавление userID в контекст
25    ctx = context.WithValue(ctx, "userID", userID)
26    return handler(ctx, req)
27}

1import (
2    "google.golang.org/grpc/codes"
3    "google.golang.org/grpc/status"
4)
5
6func (s *server) GetUser(ctx context.Context, req *userpb.GetUserRequest) (*userpb.User, error) {
7    user := db.Find(req.Id)
8    if user == nil {
9        return nil, status.Errorf(codes.NotFound, "user %d not found", req.Id)
10    }
11    return user, nil
12}