テストコンテナを使用したGoアプリケーションのローカル開発

package main

import (
   "log"
   "os"

   "github.com/gofiber/fiber/v2"
)

func main() {
   app := fiber.New()

   app.Get("/", func(c *fiber.Ctx) error {
       return c.SendString("Hello, World!")
   })

   log.Fatal(app.Listen(":8000"))
}

// MyApp is the main application, including the fiber app and the postgres container
type MyApp struct {
   // The name of the app
   Name string
   // The version of the app
   Version string
   // The fiber app
   FiberApp *fiber.App
   // The database connection string for the users database. The application will need it to connect to the database,
   // reading it from the USERS_CONNECTION environment variable in production, or from the container in development.
   UsersConnection string
}

var App *MyApp = &MyApp{
   Name:            "my-app",
   Version:         "0.0.1",
   // in production, the URL will come from the environment
   UsersConnection: os.Getenv("USERS_CONNECTION"),
}

func main() {
   app := fiber.New()

   app.Get("/", func(c *fiber.Ctx) error {
      return c.SendString("Hello, World!")
   })

   // register the fiber app
   App.FiberApp = app

   log.Fatal(app.Listen(":8000"))
}

// +build dev
// go:build dev

func init() {
   // Do something
}

//go:build dev
// +build dev

package main

import (
   "context"
   "log"
   "path/filepath"
   "time"

   "github.com/jackc/pgx/v5"
   "github.com/testcontainers/testcontainers-go"
   "github.com/testcontainers/testcontainers-go/modules/postgres"
   "github.com/testcontainers/testcontainers-go/wait"
)

func init() {
   ctx := context.Background()

   c, err := postgres.RunContainer(ctx,
       testcontainers.WithImage("postgres:15.3-alpine"),
       postgres.WithInitScripts(filepath.Join(".", "testdata", "dev-db.sql")),
       postgres.WithDatabase("users-db"),
       postgres.WithUsername("postgres"),
       postgres.WithPassword("postgres"),
       testcontainers.WithWaitStrategy(
           wait.ForLog("database system is ready to accept connections").
               WithOccurrence(2).WithStartupTimeout(5*time.Second)),
   )
   if err != nil {
       panic(err)
   }

   connStr, err := c.ConnectionString(ctx, "sslmode=disable")
   if err != nil {
       panic(err)
   }

   // check the connection to the database
   conn, err := pgx.Connect(ctx, connStr)
   if err != nil {
       panic(err)
   }
   defer conn.Close(ctx)

   App.UsersConnection = connStr
   log.Println("Users database started successfully")
}

go run -tags dev .

//go:build dev
// +build dev

package main

import (
    "context"
    "fmt"
    "log"
    "os"
    "os/signal"
    "path/filepath"
    "syscall"
    "time"

    "github.com/jackc/pgx/v5"
    "github.com/testcontainers/testcontainers-go"
    "github.com/testcontainers/testcontainers-go/modules/postgres"
    "github.com/testcontainers/testcontainers-go/wait"
)

func init() {
    ctx := context.Background()

    c, err := postgres.RunContainer(ctx,
        testcontainers.WithImage("postgres:15.3-alpine"),
        postgres.WithInitScripts(filepath.Join(".", "testdata", "dev-db.sql")),
        postgres.WithDatabase("users-db"),
        postgres.WithUsername("postgres"),
        postgres.WithPassword("postgres"),
        testcontainers.WithWaitStrategy(
            wait.ForLog("database system is ready to accept connections").
                WithOccurrence(2).WithStartupTimeout(5*time.Second)),
    )
    if err != nil {
        panic(err)
    }

    connStr, err := c.ConnectionString(ctx, "sslmode=disable")
    if err != nil {
        panic(err)
    }

    // check the connection to the database
    conn, err := pgx.Connect(ctx, connStr)
    if err != nil {
        panic(err)
    }
    defer conn.Close(ctx)

    App.UsersConnection = connStr
    log.Println("Users database started successfully")

    // register a graceful shutdown to stop the dependencies when the application is stopped
    // only in development mode
    var gracefulStop = make(chan os.Signal)
    signal.Notify(gracefulStop, syscall.SIGTERM)
    signal.Notify(gracefulStop, syscall.SIGINT)
    go func() {
        sig := <-gracefulStop
        fmt.Printf("caught sig: %+v\n", sig)
        err := shutdownDependencies()
        if err != nil {
            os.Exit(1)
        }
        os.Exit(0)
    }()
}

// helper function to stop the dependencies
func shutdownDependencies(containers ...testcontainers.Container) error {
    ctx := context.Background()
    for _, c := range containers {
        err := c.Terminate(ctx)
        if err != nil {
            log.Println("Error terminating the backend dependency:", err)
            return err
        }
    }

    return nil
}

var App *MyApp = &MyApp{
   Name:            "my-app",
   Version:         "0.0.1",
   DevDependencies: []DevDependency{},
   // in production, the URL will come from the environment
   UsersConnection: os.Getenv("USERS_CONNECTION"),
}