Docker Usage#

This document provides a basic guide to using Docker, including common commands and concepts relevant to a development workflow.

Overview#

Docker is a platform for developing, shipping, and running applications in containers. Containers allow you to package an application with all of its dependencies into a standardized unit for software development.

Installation#

Docker Desktop: For macOS and Windows, Docker Desktop is the easiest way to install Docker. It includes the Docker Engine, Docker CLI client, Docker Compose, Kubernetes, and more.
Linux: On Linux, you can install the Docker Engine and CLI separately. Follow the official installation guides for your distribution (e.g., Install Docker Engine on Ubuntu).

Installation might be managed by chezmoi if Docker is part of your standard toolset defined in your dotfiles.

Common Docker CLI Commands#

Here are some of the most frequently used Docker commands:

Pull an image from a registry (e.g., Docker Hub):

docker pull <image_name>:<tag>
# Example: docker pull ubuntu:latest

Run a container from an image:

docker run [options] <image_name>:<tag> [command]
# Example (interactive shell in an Ubuntu container):
# docker run -it ubuntu:latest /bin/bash
# Example (run a web server, map port 8080 to container's port 80):
# docker run -d -p 8080:80 nginx:latest

-d: Detached mode (run in background)
-it: Interactive TTY
-p <host_port>:<container_port>: Port mapping
--name <container_name>: Assign a name to the container
-v <host_path>:<container_path>: Mount a volume

List running containers:
```
docker ps
```
List all containers (running and stopped):
```
docker ps -a
```

View logs of a container:

docker logs <container_name_or_id>
# Follow logs: docker logs -f <container_name_or_id>

Stop a running container:
```
docker stop <container_name_or_id>
```
Remove a stopped container:
```
docker rm <container_name_or_id>
```
List images:
```
docker images
```
Remove an image:
```
docker rmi <image_name_or_id>
```

Clean up unused resources (containers, networks, images):

docker system prune
# To remove all unused images, not just dangling ones:
# docker system prune -a

Docker Compose#

Docker Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file (docker-compose.yml) to configure your application's services.

Example `docker-compose.yml` snippet:#

version: '3.8'
services:
  web:
    image: nginx:latest
    ports:
      - "8080:80"
  app:
    image: my-custom-app
    build: .
    ports:
      - "3000:3000"

Common Docker Compose Commands:#

Start services defined in docker-compose.yml:

docker-compose up
# Start in detached mode: docker-compose up -d

Stop services:
```
docker-compose down
```
List services:
```
docker-compose ps
```

Development Containers (Dev Containers)#

Development Containers (Dev Containers) allow you to use a Docker container as a full-featured development environment. This is particularly useful with editors like VS Code.

A devcontainer.json file in your project tells VS Code (and other tools) how to access (or create) a development container with a well-defined tool and runtime stack.

Key Benefits:#

Consistent Environment: Ensures everyone on the team uses the same development environment.
Tool Isolation: Keeps tools and dependencies for different projects separate.
Pre-configured Setups: Quickly onboard new developers with ready-to-use environments.

Refer to the official Dev Containers documentation and the VS Code Remote - Containers documentation for setup and usage details.

Resources#

Official Docker Documentation: https://docs.docker.com/
Docker Hub (Image Registry): https://hub.docker.com/
Docker Compose Documentation: https://docs.docker.com/compose/
Development Containers: https://containers.dev/
VS Code Remote - Containers: https://code.visualstudio.com/docs/devcontainers/containers (Note: VS Code documentation now prefers /devcontainers/ over /remote/)

This guide provides a starting point. Docker is a vast ecosystem, so refer to the official documentation for in-depth information.