.devcontainer

compose.yaml

name: my-app

services:
  rails-app:
    build:
      context: ..
      dockerfile: .devcontainer/Dockerfile

    volumes:
    - ..:/workspace:cached

    # Overrides default command so things don't shut down after the process ends.
    command: sleep infinity

    # Uncomment the next line to use a non-root user for all processes.
    # user: vscode

    # Use "forwardPorts" in **devcontainer.json** to forward an app port locally.
    # (Adding the "ports" property to this file will not forward from a Codespace.)
    depends_on:
    - postgres

  postgres:
    image: postgres:16.1
    restart: unless-stopped
    networks:
    - default
    volumes:
    - postgres-data:/var/lib/postgresql/data
    environment:
        POSTGRES_USER: postgres
        POSTGRES_PASSWORD: postgres

volumes:
  postgres-data:

devcontainer.json

// For format details, see https://containers.dev/implementors/json_reference/.
// For config options, see the README at: https://github.com/devcontainers/templates/tree/main/src/ruby
{
  "name": "my-app",
  "dockerComposeFile": "compose.yaml",
  "service": "rails-app",
  "workspaceFolder": "/workspace",
  // Features to add to the dev container. More info: https://containers.dev/features.
  "features": {
    "ghcr.io/devcontainers/features/github-cli:1": {},
    "ghcr.io/rails/devcontainer/features/activestorage": {},
    "ghcr.io/rails/devcontainer/features/postgres-client": {}
  },
  "containerEnv": {
    "DB_HOST": "postgres"
  },
  // Use 'forwardPorts' to make a list of ports inside the container available locally.
  "forwardPorts": [
    3000,
    5432
  ],
  // Configure tool-specific properties.
  // "customizations": {},
  // Uncomment to connect as root instead. More info: https://containers.dev/implementors/json_reference/#remoteUser.
  // "remoteUser": "root",
  // Use 'postCreateCommand' to run commands after the container is created.
  "postCreateCommand": "bin/setup --skip-server"
}

Dockerfile

# Make sure RUBY_VERSION matches the Ruby version in .ruby-version
ARG RUBY_VERSION=3.4.4
FROM ghcr.io/rails/devcontainer/images/ruby:$RUBY_VERSION