Golang を使用して基本的なマイクロサービス オンライン ストア バックエンドを構築する - API ゲートウェイ パターンを使用する - パート 1

/online-store ├── api-gateway/ ├──── cmd/ ├────── main.go ├──── internal/ ├────── handler/ ├──────── handler.go ├── services/ ├──── user-service/ ├────── cmd/ ├──────── main.go ├────── internal/ ├──────── handler/ ├────────── handler.go ├────── proto/ ├──────── user-proto ├────── Dockerfile ├──── / ├── docker-compose.yml └── README.md

git clone https://github.com/googleapis/googleapis.git

syntax = "proto3"; package order; option go_package = "."; import "google/api/annotations.proto"; service OrderService { rpc GetMyOrder(GetMyOrderRequest) returns (GetMyOrderResponse) { option (google.api.http) = { get: "/v1/order/my" }; } } message GetMyOrderRequest { string user_id = 1; } message GetMyOrderResponse { string user_id = 1; string order_id = 2; string product_id = 3; int32 quantity = 4; float price = 5; string status = 6; }

protoc --proto_path="services/user-service/proto" \ --go_out="services/user-service/pb" \ --go-grpc_out="services/user-service/pb" \ --grpc-gateway_out="services/user-service/pb" \ "services/user-service/proto/user.proto"

#!/bin/bash # Error handling function handle_error() { echo "Error occurred in script at line: $1" exit 1 } # Trap any error and call the handle_error function trap 'handle_error $LINENO' ERR # Declare an associative array to map proto directories to their corresponding pb directories declare -A dir_map=( ["services/user-service/proto"]="services/user-service/pb" # you can add another directory here # e.g ["services/order-service/proto"]="services/order-service/pb" ) # Define Static Dir Path GOOGLEAPIS_DIR="googleapis" API_GATEWAY_PB_DIR="api-gateway/pb" # Ensure the API_GATEWAY_PB_DIR exists if [ ! -d "$API_GATEWAY_PB_DIR" ]; then mkdir -p "$API_GATEWAY_PB_DIR" echo "Directory $API_GATEWAY_PB_DIR created." else echo "Directory $API_GATEWAY_PB_DIR already exists." fi # Loop through the associative array and generate Go code for each proto directory for proto_dir in "${!dir_map[@]}"; do pb_dir="${dir_map[$proto_dir]}" # Check if the pb directory exists, if not, create it if [ ! -d "$pb_dir" ]; then mkdir -p "$pb_dir" echo "Directory $pb_dir created." else echo "Directory $pb_dir already exists." fi # Process each .proto file in the proto directory for proto_file in "$proto_dir"/*.proto; do # Ensure the proto file exists if [ -f "$proto_file" ]; then # Generate Go code for the current proto file protoc --proto_path="$proto_dir" \ --proto_path="$GOOGLEAPIS_DIR" \ --go_out="$pb_dir" \ --go-grpc_out="$pb_dir" \ --grpc-gateway_out="$pb_dir" \ "$proto_file" echo "Generated Go code for $proto_file" # Copy the generated Go code to the API Gateway directory cp -auv "$pb_dir"/* "$API_GATEWAY_PB_DIR/" echo "Copied generated Go code to $API_GATEWAY_PB_DIR from $pb_dir" else echo "No .proto files found in $proto_dir." fi done done

./scripts/generate-proto.sh

go get github.com/grpc-ecosystem/grpc-gateway/v2 go get google.golang.org/genproto/googleapis/api go get .golang.org/protobuf

package handler import ( "context" "log" pb "user-service/pb" "google.golang.org/grpc" ) // server implements the UserServiceServer interface type server struct { pb.UnimplementedUserServiceServer } // NewServer creates a new instance of server func NewServer() pb.UserServiceServer { return &server{} } // Implement the methods defined in your proto file here func (s *server) GetUser(ctx context.Context, req *pb.GetUserRequest) (*pb.GetUserResponse, error) { // Log the request details log.Printf("Received GetUser request with ID: %s", req.GetId()) // Implement your logic to get user information response := &pb.GetUserResponse{ Id: req.GetId(), Name: "John Doe", Email: "john.doe@example.com", } // Log the response details log.Printf("Returning GetUser response: %+v", response) return response, nil } // Implement GetUserProfile method func (s *server) GetUserProfile(ctx context.Context, req *pb.GetUserProfileRequest) (*pb.GetUserProfileResponse, error) { // Log the request details log.Printf("Received GetUserProfile request with ID: %s", req.GetId()) response := &pb.GetUserProfileResponse{ Id: req.GetId(), Name: "John Doe", Email: "john.doe@example.com", Phone: "1234567890", Address: "123 Main St", } // Log the response details log.Printf("Returning GetUserProfile response: %+v", response) return response, nil } // RegisterServices registers the gRPC services with the server func RegisterServices(s *grpc.Server) { pb.RegisterUserServiceServer(s, NewServer()) }

go get google.golang.org/grpc

package main import ( "log" "net" "google.golang.org/grpc" "google.golang.org/grpc/reflection" "user-service/internal/handler" ) func main() { // Create a new gRPC server s := grpc.NewServer() // Register the server with the gRPC server handler.RegisterServices(s) // Register reflection service on gRPC server reflection.Register(s) // Listen on port 50051 lis, err := net.Listen("tcp", ":50051") if err != nil { log.Fatalf("failed to listen: %v", err) } // Start the gRPC server log.Println("Starting gRPC server on :50051") if err := s.Serve(lis); err != nil { log.Fatalf("failed to serve: %v", err) } }

# Stage 1: Build FROM golang:1.23 AS builder WORKDIR /app # Copy go mod and sum files COPY go.mod go.sum ./ RUN go mod download # Copy the application code COPY . . # Build the Go application RUN go build -o user-service ./cmd # Stage 2: Run FROM ubuntu:22.04 # Install necessary libraries RUN apt-get update && apt-get install -y \ ca-certificates \ libc6 \ && rm -rf /var/lib/apt/lists/* WORKDIR /app # Copy the binary from the build stage COPY --from=builder /app/user-service /app/user-service ENTRYPOINT ["/app/user-service"] # Expose port EXPOSE 50051

package handler import ( "context" "log" "github.com/grpc-ecosystem/grpc-gateway/v2/runtime" "google.golang.org/grpc" pb "api-gateway/pb" ) // ServiceConfig holds the configuration for each service. type ServiceConfig struct { Name string Address string } // RegisterServices registers all services with the mux based on the given service configurations. func RegisterServices(ctx context.Context, mux *runtime.ServeMux, services []ServiceConfig) error { for _, svc := range services { opts := []grpc.DialOption{grpc.WithInsecure()} var err error switch svc.Name { case "UserService": err = pb.RegisterUserServiceHandlerFromEndpoint(ctx, mux, svc.Address, opts) // We can create another cases for another services default: log.Printf("No handler implemented for service %s", svc.Name) continue } if err != nil { return err } log.Printf("Registered service %s at %s", svc.Name, svc.Address) } return nil }

go get github.com/grpc-ecosystem/grpc-gateway go get google.golang.org/grpc

package main import ( "context" "log" "net/http" "github.com/grpc-ecosystem/grpc-gateway/v2/runtime" "api-gateway/internal/handler" ) func main() { // Define service configurations services := []handler.ServiceConfig{ {Name: "UserService", Address: "user-service:50051"}, // You can add another services here } ctx := context.Background() ctx, cancel := context.WithCancel(ctx) defer cancel() mux := runtime.NewServeMux() // Register services if err := handler.RegisterServices(ctx, mux, services); err != nil { log.Fatalf("Failed to register services: %v", err) } // Start the HTTP server if err := http.ListenAndServe(":8080", mux); err != nil { log.Fatalf("Failed to start HTTP server: %v", err) } }

# Stage 1: Build FROM golang:1.23 AS builder WORKDIR /app # Copy go mod and sum files COPY go.mod go.sum ./ RUN go mod download # Copy the application code COPY . . # Build the Go application RUN go build -o main ./cmd # Stage 2: Run FROM ubuntu:22.04 # Install necessary libraries RUN apt-get update && apt-get install -y \ ca-certificates \ libc6 \ && rm -rf /var/lib/apt/lists/* WORKDIR /app # Copy the binary from the build stage COPY --from=builder /app/main /app/main ENTRYPOINT ["/app/main"] # Expose port (if necessary) EXPOSE 8080

version: '4.0' services: api-gateway: build: ./api-gateway ports: - "8080:8080" depends_on: - user-service user-service: build: context: ./services/user-service dockerfile: Dockerfile ports: - "50051:50051" # Can put another service here

docker-compose up --build -d

docker ps

docker logs --follow user-service-1