How to Quickly Get a Running Development Environment

.devcontainer.json

{
    "name": "hello-devcontainers",
    "dockerComposeFile": "docker-compose.yml",
    "service": "devcontainer",
    "features": {
        "ghcr.io/devcontainers-contrib/features/apt-get-packages:1": {
            "packages": "inotify-tools,bash-completion"
        }
    },
    "customizations": {
        "vscode": {
            "settings": {},
            "extensions": [
                "golang.go"
            ]
        }
    },
    "containerUser": "vscode"
}

docker-compose.yml

version: "3.8"

services:
  devcontainer:
    image: mcr.microsoft.com/devcontainers/go:1
    userns_mode: keep-id
    volumes:
      - .:/workspaces/hello-devcontainers:cached
    command: sleep infinity
    depends_on:
      - db
    links:
      - db
    environment:
      DB_DSN: "hello:.test.@tcp(db:3306)/hello?charset=utf8&parseTime=True"
  db:
    image: docker.io/library/mariadb:11
    restart: unless-stopped
    environment:
      - MARIADB_DATABASE=hello
      - MARIADB_USER=hello
      - MARIADB_PASSWORD=.test.
      - MARIADB_ALLOW_EMPTY_ROOT_PASSWORD=1
    volumes:
      - ../data:/var/lib/mysql
    ports:
      - 3306:3306

go.mod

module hello-devcontainers

go 1.22.1

require github.com/go-sql-driver/mysql v1.8.1

require filippo.io/edwards25519 v1.1.0 // indirect

go.sum

filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
github.com/go-sql-driver/mysql v1.8.1 h1:LedoTUt/eveggdHS9qUFC1EFSa8bU2+1pZjSRpvNJ1Y=
github.com/go-sql-driver/mysql v1.8.1/go.mod h1:wEBSXgmK//2ZFJyE+qWnIsVGmvmEKlqwuVSjsCm7DZg=

main.go

package main

import (
	"database/sql"
	"fmt"
	"log"
	"net/http"
	"os"

	_ "github.com/go-sql-driver/mysql"
)

func main() {
	dsn := os.Getenv("DB_DSN")
	if dsn == "" {
		log.Fatal("DB_DSN environment variable is not set")
	}

	db, err := sql.Open("mysql", dsn)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello, World!\n")

		var result int
		err = db.QueryRow("SELECT 1").Scan(&result)
		if err != nil {
			log.Fatal(err)
		}

		if result == 1 {
			fmt.Fprintf(w, "MariaDB was responding!\n")
		}
	})

	if err := http.ListenAndServe(":9080", nil); err != nil {
		fmt.Println("Error starting server:", err)
	}
}