draft/assets/templates/main.go.tpl

package main

import (
	"context"
	{{ if .UseGRPC }}
	"errors"
	"net"
	"net/http"
	{{ end }}
	"os"
	"os/signal"
	"syscall"

	"github.com/hibiken/asynq"
	{{ if .UseGRPC }}
	"github.com/rs/cors"
	{{ end }}
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"golang.org/x/sync/errgroup"

	"{{ .ModuleName }}/internal/auth"
	"{{ .ModuleName }}/internal/config"
	db "{{ .ModuleName }}/internal/db/sqlc"
	{{ if .UseGRPC }}
	gapi "{{ .ModuleName }}/internal/handlers/grpc"
	{{ end }}
	{{ if not .UseGRPC }}
	api "{{ .ModuleName }}/internal/handlers/http"
	{{ end }}
	"{{ .ModuleName }}/internal/mailer"
	"{{ .ModuleName }}/internal/service"
	"{{ .ModuleName }}/internal/worker"
	{{ if .UseGRPC }}
	"{{ .ModuleName }}/pb"
	{{ end }}

	"github.com/golang-migrate/migrate/v4"
	_ "github.com/golang-migrate/migrate/v4/database/postgres"
	_ "github.com/golang-migrate/migrate/v4/source/file"
	{{ if .UseGRPC }}
	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
	"github.com/rakyll/statik/fs"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
	"google.golang.org/protobuf/encoding/protojson"

	_ "{{ .ModuleName }}/docs/statik"
	{{ end }}
	"github.com/jackc/pgx/v5/pgxpool"
	_ "github.com/jackc/pgx/v5/stdlib"


)

var interruptSignals = []os.Signal{
	os.Interrupt,
	syscall.SIGTERM,
	syscall.SIGINT,
}

// @title Simple Bank API
// @version 1.0
// @description API for Simple Bank application
// @termsOfService http://swagger.io/terms/

// @contact.name API Support
// @contact.email [email protected]

// @license.name MIT
// @license.url https://opensource.org/licenses/MIT

// @host localhost:8080
// @BasePath /v1
// @schemes http https

// @securityDefinitions.apikey BearerAuth
// @in header
// @name Authorization
// @description Type "Bearer" followed by a space and JWT token.
func main() {
	config, err := config.LoadConfig(".")
	if err != nil {
		log.Fatal().Err(err).Msg("cannot load config")
	}

	if config.Environment == "development" {
		log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
	}

	ctx, cancel := signal.NotifyContext(context.Background(), interruptSignals...)
	defer cancel()

	connPool, err := pgxpool.New(ctx, config.DBAddr)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot connect to db")
	}

	runDBMigration(config.MigrationURL, config.DBAddr)

	redisOpt := asynq.RedisClientOpt{
		Addr:     config.RedisAddr,
		Password: config.RedisPassword,
		DB:       config.RedisDB,
	}

	taskDist := worker.NewRedisTaskDistributor(redisOpt)
	store := db.NewPostgresStore(connPool)

	tokenMaker, err := auth.NewPasetoMaker(config)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create token maker")
	}

	userService := service.NewUserService(store, taskDist)
	authService := service.NewAuthService(store, tokenMaker, config)

	wg, ctx := errgroup.WithContext(ctx)

	{{ if not .UseGRPC }}
	runGinServer(ctx, wg, config, store, taskDist, tokenMaker, userService, authService)
	{{ else }}
	// Assuming you want Gateway AND gRPC when gRPC is selected
	runGatewayServer(ctx, wg, config, store, taskDist, tokenMaker, userService, authService)
	runGrpcServer(ctx, wg, config, store, taskDist, tokenMaker, userService, authService)
	{{ end }}

	runTaskProcessor(ctx, wg, redisOpt, store, config)

	err = wg.Wait()
	if err != nil {
		log.Fatal().Err(err).Msg("application terminated with error")
	}
}

func runTaskProcessor(ctx context.Context, wg *errgroup.Group, redisOpt asynq.RedisClientOpt, store db.Store, config config.Config) {
	mailer := mailer.NewGmailSender(config.EmailSenderName, config.EmailSender, config.EmailPassword)
	taskProcessor := worker.NewRedisTaskProcessor(redisOpt, store, mailer, config)
	log.Info().Msg("start task processor")
	if err := taskProcessor.Start(); err != nil {
		log.Fatal().Err(err).Msg("cannot start task processor")
	}

	wg.Go(func() error {
		<-ctx.Done()
		log.Info().Msg("gracefully shutting down task processor")
		taskProcessor.Shutdown()
		log.Info().Msg("task processor shut down")
		return nil
	})
}

func runDBMigration(migrationURL, dbSource string) {
	migration, err := migrate.New(migrationURL, dbSource)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create new migrate instance")
	}

	if err = migration.Up(); err != nil && err != migrate.ErrNoChange {
		log.Fatal().Err(err).Msg("failed to run migrate up")
	}

	log.Info().Msg("db migrated successfully")
}

{{ if not .UseGRPC }}
func runGinServer(ctx context.Context, wg *errgroup.Group, config config.Config, store db.Store, td worker.TaskDistributor, tokenMaker auth.Maker, userService service.UserService, authService service.AuthService) {
	s, err := api.NewServer(config, store, td, tokenMaker, userService, authService)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create server")
	}

	wg.Go(func() error {
		err = s.Start(config.HTTPServerAddr)
		if err != nil {
			log.Fatal().Err(err).Msg("cannot start server:")
			return err
		}
		return nil
	})

	wg.Go(func() error {
		<-ctx.Done()
		log.Info().Msg("shutting down server")
		err := s.Shutdown(ctx)
		if err != nil {
			log.Error().Err(err).Msg("cannot shutdown server")
			return err
		}
		log.Info().Msg("server shut down")
		return nil
	})
}
{{ end }}

{{ if .UseGRPC }}
func runGrpcServer(ctx context.Context, wg *errgroup.Group, config config.Config, store db.Store, taskDistributor worker.TaskDistributor, tokenMaker auth.Maker, userService service.UserService, authService service.AuthService) {
	server, err := gapi.NewServer(config, store, taskDistributor, tokenMaker, userService, authService)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create server:")
	}

	grpcLogger := grpc.UnaryInterceptor(gapi.GrpcLogger)

	grpcServer := grpc.NewServer(grpcLogger)
	pb.RegisterSimpleBankServer(grpcServer, server)
	reflection.Register(grpcServer)

	listener, err := net.Listen("tcp", config.GrpcServerAddr)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create listener")
	}

	wg.Go(func() error {
		log.Info().Msgf("start gRPC server at %s", listener.Addr().String())
		err = grpcServer.Serve(listener)
		if err != nil {
			if errors.Is(err, grpc.ErrServerStopped) {
				return nil
			}
			log.Error().Err(err).Msg("gRPC server failed to serve")
			return err
		}
		return nil
	})

	wg.Go(func() error {
		<-ctx.Done()
		log.Info().Msg("gracefully shutting down gRPC server")
		grpcServer.GracefulStop()
		log.Info().Msg("gRPC server shut down")
		return nil
	})
}

func runGatewayServer(ctx context.Context, wg *errgroup.Group, config config.Config, store db.Store, taskDistributor worker.TaskDistributor, tokenMaker auth.Maker, userService service.UserService, authService service.AuthService) {
	server, err := gapi.NewServer(config, store, taskDistributor, tokenMaker, userService, authService)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create server:")
	}

	opts := runtime.WithMarshalerOption(runtime.MIMEWildcard, &runtime.JSONPb{
		MarshalOptions: protojson.MarshalOptions{
			UseProtoNames: true,
		},
		UnmarshalOptions: protojson.UnmarshalOptions{
			DiscardUnknown: true,
		},
	})

	grpcMux := runtime.NewServeMux(opts)

	err = pb.RegisterSimpleBankHandlerServer(ctx, grpcMux, server)
	if err != nil {
		log.Fatal().Err(err).Msg("cannot register handler server")
	}

	mux := http.NewServeMux()
	mux.Handle("/", grpcMux)

	statikFS, err := fs.New()
	if err != nil {
		log.Fatal().Err(err).Msg("cannot create statik fs")
	}

	swaggerHandler := http.StripPrefix("/swagger/", http.FileServer(statikFS))
	mux.Handle("/swagger/", swaggerHandler)

	c := cors.New(
		cors.Options{
			AllowedOrigins: config.AllowedOrigins,
			AllowedMethods: []string{
				http.MethodGet,
				http.MethodPost,
				http.MethodPut,
				http.MethodPatch,
				http.MethodDelete,
				http.MethodOptions,
			},
			AllowedHeaders: []string{
				"Accept",
				"Authorization",
				"Content-Type",
				"X-CSRF-Token",
			},
			AllowCredentials: true,
			Debug:            config.Environment == "development",
		},
	)
	handler := c.Handler(gapi.HTTPLogger(mux))
	httpServer := &http.Server{
		Handler: handler,
		Addr:    config.HTTPServerAddr,
	}

	wg.Go(func() error {
		log.Info().Msgf("start HTTP gateway server at %s", httpServer.Addr)

		err = httpServer.ListenAndServe()
		if err != nil {
			if errors.Is(err, http.ErrServerClosed) {
				return nil
			}
			log.Error().Err(err).Msg("cannot start http gateway server")
			return err
		}
		return nil
	})

	wg.Go(func() error {
		<-ctx.Done()
		log.Info().Msg("gracefully shutting down HTTP gateway server")
		err := httpServer.Shutdown(context.Background())
		if err != nil {
			log.Error().Err(err).Msg("cannot shut down http gateway server")
			return err
		}
		log.Info().Msg("HTTP gateway server shut down")
		return nil
	})

}
{{ end }}