users/cmd/server/main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net"
	"net/http"
	"os"

	"git.chrishayward.xyz/x/users/proto"
	"git.chrishayward.xyz/x/users/server"
	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
	"gopkg.in/yaml.v3"
	"gorm.io/driver/postgres"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

var configPath = flag.String("config", "./config/server.yaml", "--config=./config/server.yaml")

type config struct {
	Port    int    `yaml:"port"`
	Secret  string `yaml:"secret"`
	Gateway struct {
		URL  string `yaml:"url"`
		Port int    `yaml:"port"`
	}
	Database struct {
		Type     string `yaml:"type"`
		File     string `yaml:"file"`
		Host     string `yaml:"host"`
		Port     int    `yaml:"port"`
		Name     string `yaml:"name"`
		User     string `yaml:"user"`
		Password string `yaml:"password"`
	} `yaml:"database"`
}

func main() {
	// Create the context.
	ctx := context.Background()
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	// Parse the application flags.
	flag.Parse()

	// Read the config file.
	config := &config{}
	file, err := os.Open(*configPath)
	if err != nil {
		log.Fatalf("Failed to open config file: %v", err)
	}
	defer file.Close()
	if err := yaml.NewDecoder(file).Decode(&config); err != nil {
		log.Fatalf("Failed to read config file: %v", err)
	}

	// Create the server network listener.
	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", config.Port))
	if err != nil {
		log.Fatal(err)
	}

	// Initialize the database.
	var db *gorm.DB
	switch config.Database.Type {
	case "postgres":
		db, _ = gorm.Open(postgres.Open(fmt.Sprintf(
			"host=%s user=%s password=%s dbname=%s port=%d sslmode=disable",
			config.Database.Host,
			config.Database.User,
			config.Database.Password,
			config.Database.Name,
			config.Database.Port)))
	case "sqlite":
		fallthrough
	default:
		db, _ = gorm.Open(sqlite.Open(config.Database.File), &gorm.Config{})
	}

	// Create the server.
	grpcServer := grpc.NewServer()
	proto.RegisterUsersServer(grpcServer, server.NewUsersServer(config.Secret, db))
	reflection.Register(grpcServer)
	go grpcServer.Serve(lis)

	// Create the gateway client connection.
	conn, err := grpc.Dial(fmt.Sprintf("localhost:%d", config.Port), grpc.WithInsecure())
	if err != nil {
		log.Fatalf("Failed to create client connection: %v", err)
	}
	defer conn.Close()

	// Create the gRPC gateway.
	rmux := runtime.NewServeMux()
	client := proto.NewUsersClient(conn)
	err = proto.RegisterUserHandlerClient(ctx, rmux, client)
	if err != nil {
		log.Fatalf("Failed to register client handler: %v", err)
	}

	// Create a standard HTTP router.
	mux := http.NewServeMux()

	// Mount the gRPC gateway.
	mux.Handle("/", rmux)

	// Create the gRPC OpenAPI UI.
	mux.HandleFunc("/swagger-ui/swagger.json", func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, "./proto/users.swagger.json")
	})
	mux.Handle("/swagger-ui/",
		http.StripPrefix("/swagger-ui/",
			http.FileServer(http.Dir("./modules/swagger-ui/dist"))))

	// Start listening for requests.
	log.Println(fmt.Sprintf("Listening on:\n=>\tgRPC[::]:%d\n=>\tHTTP[::]:%d",
		config.Port, config.Gateway.Port))
	err = http.ListenAndServe(fmt.Sprintf(":%d", config.Gateway.Port), mux)
	if err != nil {
		log.Fatalf("Failed to listen: %v", err)
	}
}