Phoenix + Docker Compose + Live Reload

brunch-config.js

exports.config = {
  // See http://brunch.io/#documentation for docs.
  files: {
    javascripts: {
      joinTo: "js/app.js"

      // To use a separate vendor.js bundle, specify two files path
      // http://brunch.io/docs/config#-files-
      // joinTo: {
      //  "js/app.js": /^(web\/static\/js)/,
      //  "js/vendor.js": /^(web\/static\/vendor)|(deps)/
      // }
      //
      // To change the order of concatenation of files, explicitly mention here
      // order: {
      //   before: [
      //     "web/static/vendor/js/jquery-2.1.1.js",
      //     "web/static/vendor/js/bootstrap.min.js"
      //   ]
      // }
    },
    stylesheets: {
      joinTo: "css/app.css",
      order: {
        after: ["web/static/css/app.css"] // concat app.css last
      }
    },
    templates: {
      joinTo: "js/app.js"
    }
  },

  conventions: {
    // This option sets where we should place non-css and non-js assets in.
    // By default, we set this to "/web/static/assets". Files in this directory
    // will be copied to `paths.public`, which is "priv/static" by default.
    assets: /^(web\/static\/assets)/
  },

  // Phoenix paths configuration
  paths: {
    // Dependencies and current project directories to watch
    watched: [
      "web/static",
      "test/static"
    ],

    // Where to compile files to
    public: "priv/static"
  },

  // Configure your plugins
  plugins: {
    babel: {
      presets: ["es2015", "es2016", "react", "stage-2"],
      // Do not use ES6 compiler in vendor code
      ignore: [/web\/static\/vendor/]
    }
  },

  modules: {
    autoRequire: {
      "js/app.js": ["web/static/js/app"]
    }
  },

  npm: {
    enabled: true
  }
};

docker-compose.yml

version: '2'
services:
  web:
    build: 
      context: .
      dockerfile: Dockerfile
    env_file: .env # touch .env if you receive an error
    command: mix phoenix.server
    environment:
      - MIX_ENV=dev
      - PORT=4000
      - PG_HOST=postgres
      - PG_USERNAME=postgres
    volumes:  
      - .:/app
    ports:
      - "4000:4000"
    links:
      - postgres

  test:
    image: <PROJECT_NAME>_web
    env_file: .env # touch .env if you receive an error
    command: mix test
    environment:
      - MIX_ENV=test
      - PORT=4001
      - PG_HOST=postgres
      - PG_USERNAME=postgres
    volumes_from:
      - web
    links:
      - postgres
    depends_on:
      - web

  postgres:
    image: postgres:9.5 # https://hub.docker.com/_/postgres/
    volumes:
      - postgres-volume:/var/lib/postgresql/data/
    expose:
      - "5432"

volumes:
  postgres-volume:
    driver: local

Dockerfile

# Starting from the official Elixir 1.3.2 image:
# https://hub.docker.com/_/elixir/
FROM elixir:1.3.2

# Based off of a Dockerfile by David Anguita <david@davidanguita.name>
MAINTAINER Cory Fabre <cfabre@gmail.com> 

ENV DEBIAN_FRONTEND=noninteractive

# Install hex
RUN mix local.hex --force

# Install rebar
RUN mix local.rebar --force

# Install the Phoenix framework itself
RUN mix archive.install --force https://github.com/phoenixframework/archives/raw/master/phoenix_new.ez

# Install NodeJS 6.x and the NPM
RUN curl -sL https://deb.nodesource.com/setup_6.x | bash -
RUN apt-get install -y -q nodejs

# Install inotify
RUN apt-get install -y -q inotify-tools

# Set /app as workdir
WORKDIR /app