Docker & Compose

docker build -t my-app:1.0 .                # build from ./Dockerfile, tag it
docker build -f Dockerfile.prod -t my-app:prod .   # use a specific Dockerfile
docker images                                # list local images
docker rmi my-app:1.0                        # remove an image
docker tag my-app:1.0 my-registry/my-app:1.0 # add a second tag (e.g. before pushing)
docker push my-registry/my-app:1.0           # push to a registry
docker pull my-registry/my-app:1.0           # pull from a registry
docker history my-app:1.0                    # show each layer and its size

docker run my-app:1.0                        # run in the foreground
docker run -d my-app:1.0                     # detached (background)
docker run -p 8080:80 my-app:1.0             # map host:container ports
docker run -e KEY=value my-app:1.0           # set an environment variable
docker run -v $(pwd)/data:/app/data my-app:1.0  # bind-mount a host directory
docker run --name my-container my-app:1.0    # give it a fixed name
docker run --rm my-app:1.0                   # auto-remove the container when it exits
docker run -it my-app:1.0 /bin/bash          # interactive shell instead of the default CMD

docker ps                          # running containers
docker ps -a                       # every container, including stopped ones
docker logs my-container            # stdout/stderr from a container
docker logs -f my-container         # follow, like `tail -f`
docker exec -it my-container bash   # shell into a running container
docker inspect my-container          # full JSON: config, mounts, network, env
docker stats                        # live CPU/memory/network usage per container
docker top my-container              # processes running inside a container

docker stop my-container             # graceful stop (SIGTERM, then SIGKILL after a timeout)
docker start my-container            # restart a stopped container
docker restart my-container          # stop + start
docker rm my-container               # remove a stopped container
docker rm -f my-container            # force-remove, even if running

docker system prune                  # remove stopped containers, dangling images, unused networks
docker system prune -a               # also remove all unused images, not just dangling ones
docker volume prune                  # remove unused volumes
docker image prune -a                # remove all images not used by an existing container

docker compose up                    # start every service defined in docker-compose.yml
docker compose up -d                 # detached
docker compose up --build            # rebuild images before starting
docker compose down                  # stop and remove containers, networks
docker compose down -v               # also remove named volumes
docker compose ps                    # status of each service
docker compose logs -f api            # follow logs for one service
docker compose exec api bash          # shell into a running service
docker compose restart api            # restart one service without touching the others

services:
  api:
    build: .
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgresql://user:pass@db:5432/app
    depends_on:
      - db
  db:
    image: postgres:16
    environment:
      - POSTGRES_PASSWORD=pass
    volumes:
      - db-data:/var/lib/postgresql/data

volumes:
  db-data: