go-todos-app/main.go

package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"path/filepath"

	pgxuuid "github.com/jackc/pgx-gofrs-uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/joho/godotenv"
	"michaelthomson.dev/mthomson/go-todos-app/handlers"
	"michaelthomson.dev/mthomson/go-todos-app/repositories"
	"michaelthomson.dev/mthomson/go-todos-app/services"
)

func main() {
  // load environment
  err := godotenv.Load()

  if err != nil {
    log.Printf("Error loading .env file: %v", err)
  }

  databaseUrl := os.Getenv("DATABASE_URL")

  // connect to Db
  dbconfig, err := pgxpool.ParseConfig(databaseUrl)
  if err != nil {
    log.Fatalf("Unable to parse db config: %v", err)
  }

  dbconfig.AfterConnect = func(ctx context.Context, conn *pgx.Conn) error {
    pgxuuid.Register(conn.TypeMap())
    return nil
  }

  dbpool, err := pgxpool.New(context.Background(), databaseUrl)
  if err != nil {
    log.Fatalf("Unable to create connection pool: %v", err)
  }
  defer dbpool.Close()

  // apply initial sql
  log.Print("Applying migrations table")
  content, err := os.ReadFile(filepath.Join("sql", "init.sql"))

  if err != nil {
    log.Fatal(err)
    os.Exit(1)
  }

  _, err = dbpool.Exec(context.Background(), string(content))

  if err != nil {
    log.Fatal(err)
    os.Exit(1)
  }

  //apply migrations
  log.Print("Starting migrations...")
  files, err := os.ReadDir("./sql/migrations")
  if err != nil {
    log.Fatal(err)
    os.Exit(1)
  }

  for _, file := range files {
    path := filepath.Join("sql", "migrations", file.Name())
    content, err := os.ReadFile(path)

    if err != nil {
      log.Fatal(err)
      os.Exit(1)
    }

    var count int
    err = dbpool.QueryRow(context.Background(), "SELECT COUNT(1) FROM migration WHERE name=$1", file.Name()).Scan(&count)

    if err != nil {
      log.Fatal(err)
      os.Exit(1)
    }

    if count == 0 {
      log.Printf("Running migration: %s", file.Name())
      _, err = dbpool.Exec(context.Background(), string(content))

      if err != nil {
	log.Fatal(err)
	os.Exit(1)
      }

      _, err = dbpool.Exec(context.Background(), "INSERT INTO migration(name) values($1)", file.Name())

      if err != nil {
	log.Fatal(err)
	os.Exit(1)
      }
    } else {
      log.Printf("Migration already exists: %s", file.Name())
    }
  }

  log.Print("Migrations complete")

  // set up repositories
  todoRepository := repositories.NewPostgresTodoRepository(dbpool)

  // set up services
  todoService := services.NewTodoService(&todoRepository)

  // set up handlers
  homeHandler := handlers.NewHomeHandler(todoService)
  todoHandler := handlers.NewTodoHandler(todoService)

  router := http.NewServeMux()

  // Serve static files
  fs := http.FileServer(http.Dir("./assets"))
  router.Handle("GET /assets/", http.StripPrefix("/assets/", fs))

  router.HandleFunc("GET /{$}", homeHandler.Home)
  router.HandleFunc("POST /todos", todoHandler.Create)
  router.HandleFunc("DELETE /todos/{id}", todoHandler.Delete)
  router.HandleFunc("PATCH /todos/{id}/done", todoHandler.Done)
  router.HandleFunc("PATCH /todos/{id}/undone", todoHandler.Undone)

  server := http.Server{
    Addr: "localhost:3000",
    Handler: router,
  }

  log.Fatal(server.ListenAndServe())
}