Compose Basics

services:
  api:
    image: myapi:1.0
# one service named api

services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"
# host 8080 -> container 80

services:
  db:
    image: postgres:16
    volumes:
      - pgdata:/var/lib/postgresql/data
volumes:
  pgdata:
# persistent named volume

services:
  api:
    image: myapi:1.0
    environment:
      PORT: "3000"
    env_file:
      - .env
# PORT=3000 in container

services:
  api:
    depends_on:
      - db
  db:
    image: postgres:16
# db starts before api

services:
  api:
    build:
      context: .
      dockerfile: Dockerfile
# docker compose build api

services:
  api:
    networks: [backend]
networks:
  backend:
# services on backend can resolve each other by name

services:
  debug:
    profiles: ["debug"]
    image: nicolaka/netshoot
# compose --profile debug up

services:
  db:
    image: postgres:16
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 5s
# Status: healthy when ready

services:
  api:
    restart: unless-stopped
# restarts on failure unless manually stopped

# bash
docker compose up -d
# [+] Running N/N

# bash
docker compose down -v
# removes containers and volumes if -v

# bash
docker compose logs -f api
# follow api logs

# bash
docker compose run --rm api npm test
# runs test container then removes it

# bash
docker compose config
# merged YAML to stdout