I am a big fan of Caddy and I use it often in POCs and personal projects. I stand by the Caddy team decision to offer the official binary distribution as a payed service and I hope it will help the project evolve and make Caddy even better.

In order to keep using the open source Apache 2.0 licensed version, I’ve made a project to automate the build process of Caddy with plugins from source using Docker multi-build and Travis CI.

Usage

Clone the caddy-builder repository:

$ git clone https://github.com/stefanprodan/caddy-builder.git
$ cd caddy-builder

Add the Caddy plugins that you want to the plugins.go file:

package caddyhttp

import (
	// http.prometheus
	_ "github.com/miekg/caddy-prometheus"
	// http.ipfilter
	_ "github.com/pyed/ipfilter"
)

Edit the docker-compose file and replace the image prefix with your own repo name:

version: "3.3"

services:
  caddy:
    build:
      context: .
      dockerfile: Dockerfile
      args:
        CADDY_VERSION: ${CADDY_VERSION:-0.10.9}
    image: stefanprodan/caddy:${CADDY_VERSION:-0.10.9}
    container_name: caddy
    ports:
      - 80:80
      - 443:443
      - 9180:9180

Build the image with Docker Compose:

CADDY_VERSION=0.10.9 docker-compose build caddy

Run Caddy container exposing 80, 443 and 9180 ports:

docker-compose up -d

Remove the container, www volume and image:

docker-compose down -v --rmi all

Build and publish to Docker Hub

You can automate the build and publish process for free with Travis CI. First create a Docker Hub repository, add your public GitHub repo to Travis CI and set the DOCKER_USER and DOCKER_PASS environments variable in the Travis project. Before triggering the fist build, replace stefanprodan with your own Docker hub user in the .travis.yml file.

sudo: required
language: generic

services:
  - docker

env:
  global:
    - CADDY_VERSION: 0.10.9
    - DOCKER_COMPOSE_VERSION: 1.16.1

before_install:
  - curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
  - sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
  - sudo apt-get update
  - sudo apt-get -y install docker-ce
  - sudo service docker restart
  - sudo rm /usr/local/bin/docker-compose
  - curl -L https://github.com/docker/compose/releases/download/${DOCKER_COMPOSE_VERSION}/docker-compose-`uname -s`-`uname -m` > docker-compose
  - chmod +x docker-compose
  - sudo mv docker-compose /usr/local/bin

script:
  - CADDY_VERSION=$CADDY_VERSION docker-compose build caddy

after_success:
  - if [ "$TRAVIS_BRANCH" == "master" ]; then
    docker login -u "$DOCKER_USER" -p "$DOCKER_PASS";
    docker tag stefanprodan/caddy:$CADDY_VERSION stefanprodan/caddy:latest;
    docker push stefanprodan/caddy:$CADDY_VERSION;
    docker push stefanprodan/caddy:latest;
    fi

When a new Caddy version is released, update the CADDY_VERSION variable, commit the changes to GitHub and Travis will publish the new image to Docker Hub.

Running Caddy with Docker

The stefanprodan/caddy comes with a default Caddyfile that you can override by mounting your own config:

$ docker run -d --name caddy \
    -v $(pwd)/Caddyfile:/etc/caddy/Caddyfile \
    -p 80:80 \
    stefanprodan/caddy

Mount your site root using the www volume:

$ docker run -d --name caddy \
    -v $(pwd)/Caddyfile:/etc/caddy/Caddyfile \
    -v $(pwd)/site:/www \
    -p 80:80 \
    stefanprodan/caddy

Expose the Prometheus metric endpoint on http://localhost:9180/metrics:

$ docker run -d --name caddy \
    -v $(pwd)/Caddyfile:/etc/caddy/Caddyfile \
    -v $(pwd)/site:/www \
    -p 80:80 -p 9180:9180 \
    stefanprodan/caddy

In your Caddyfile configure the http.prometheus plugin:

example.com {
    prometheus 0.0.0.0:9180
    log stdout
    errors stderr
}

Persist Let’s Encrypt certificates on host:

$ docker run -d --name caddy \
    -v $(pwd)/Caddyfile:/etc/caddy/Caddyfile \
    -v $(pwd)/certs:/.caddy \
    -p 80:80 -p 443:443 \
    stefanprodan/caddy

In your Caddyfile configure the tls email:

example.com {
    tls contact@example.com
}

Running Caddy on Docker Swarm

In order to deploy Caddy with a custom config on Docker Swarm, you need to use Docker engine version 17.06 or later. The Caddy image has curl installed so you can easily define a health check:

version: "3.3"

configs:
  caddy_config:
    file: ./Caddyfile

volumes:
  certs: {}

services:
  caddy:
    image: stefanprodan/caddy
    ports:
      - 80:80
      - 443:443
    configs:
      - source: caddy_config
        target: /etc/caddy/Caddyfile
    volumes:
      - certs:/.caddy
    deploy:
      mode: replicated
      replicas: 1    
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:80"]
      interval: 5s
      timeout: 1s
      retries: 3

License

The caddy-builder is MIT licensed and the Caddy source code is Apache 2.0 licensed. Because stefanprodan/caddy is built from source, it’s not subject to the EULA for Caddy’s official binary distributions. If you plan to use Caddy for commercial purposes you should run the official Caddy distribution.