Sample Docer+Phoenix project

.gitignore

# App artifacts
/_build
/db
/deps
/*.ez

# Generate on crash by the VM
erl_crash.dump

# The config/prod.secret.exs file by default contains sensitive
# data and you should not commit it into version control.
#
# Alternatively, you may comment the line below and commit the
# secrets file as long as you replace its contents by environment
# variables.
/config/prod.secret.exs

config-dev.exs

use Mix.Config

# For development, we disable any cache and enable
# debugging and code reloading.
#
# The watchers configuration can be used to run external
# watchers to your application. For example, we use it
# with brunch.io to recompile .js and .css sources.
config :hi_phoenix, HiPhoenix.Endpoint,
  http: [port: 4000],
  debug_errors: true,
  code_reloader: true,
  cache_static_lookup: false,
  check_origin: false,
  watchers: []

# Watch static and templates for browser reloading.
config :hi_phoenix, HiPhoenix.Endpoint,
  live_reload: [
    patterns: [
      ~r{priv/static/.*(js|css|png|jpeg|jpg|gif|svg)$},
      ~r{web/views/.*(ex)$},
      ~r{web/templates/.*(eex)$}
    ]
  ]

# Do not include metadata nor timestamps in development logs
config :logger, :console, format: "[$level] $message\n"

# Set a higher stacktrace during development.
# Do not configure such in production as keeping
# and calculating stacktraces is usually expensive.
config :phoenix, :stacktrace_depth, 20

# Configure your database
config :hi_phoenix, HiPhoenix.Repo,
  adapter: Ecto.Adapters.Postgres,
  url: System.get_env("DATABASE_URL"),
  pool_size: 10

development-entrypoint.sh

#! /bin/bash

set -e

: ${APP_PATH:="/usr/src/app"}
: ${APP_TEMP_PATH:="$APP_PATH/tmp"}
: ${APP_SETUP_LOCK:="$APP_TEMP_PATH/setup.lock"}
: ${APP_SETUP_WAIT:="5"}

# 1: Define the functions lock and unlock our app containers setup processes:
function lock_setup { mkdir -p $APP_TEMP_PATH && touch $APP_SETUP_LOCK; }
function unlock_setup { rm -rf $APP_SETUP_LOCK; }
function wait_setup { echo "Waiting for app setup to finish..."; sleep $APP_SETUP_WAIT; }

# 2: 'Unlock' the setup process if the script exits prematurely:
trap unlock_setup HUP INT QUIT KILL TERM

# 3: Wait until the setup 'lock' file no longer exists:
while [ -f $APP_SETUP_LOCK ]; do wait_setup; done

# 4: 'Lock' the setup process, to prevent a race condition when the project's
# app containers will try to install gems and setup the database concurrently:
lock_setup

# 5: Check or install the app dependencies via Mix:
mix deps.get

# X: Check if the database exists, or setup the database if it doesn't, as it is
# the case when the project runs for the first time.
mix ecto.create

# 7: 'Unlock' the setup process:
unlock_setup

# 8: Especificar el comando default:
if [ -z "$1" ]; then set -- mix phoenix.server "$@"; fi

# 9: If the command to execute is 'rails server', then force it to write the pid
# file into an private directory - suddenly killing and removing app containers
# without this would leave a pidfile in the project's tmp dir, preventing containers
# from starting up on further attempts:
# if [[ "$1" = "rails" && ("$2" = "s" || "$2" = "server") ]]; then set -- "$@" -P /tmp/server.pid; fi

# 10: Execute the given or default command:
exec "$@"

development.Dockerfile

# This should be very similar to an official Phoenix Docker Image:

# 1: Begin with the elixir image, which should include Erlang+rebar & Elixir+Hex:
FROM elixir:1.1.1

# 2: Make a base install of Phoenix... which is just needed for... wtf???
ENV PHOENIX_VERSION=1.0.3
RUN PHOENIX_DOWNLOAD_SHA512=68cd993932140cde233a0ac35a9927799e58b81235b9e8a95d75800137eaebf9f6a603131faa7b9c5b4cac049f5f8590fd73275d83fb6c59462ab61bd7b0605a \
 && mix archive.install --force --sha512 $PHOENIX_DOWNLOAD_SHA512 \
    https://github.com/phoenixframework/phoenix/releases/download/v${PHOENIX_VERSION}/phoenix_new-${PHOENIX_VERSION}.ez

# 3: Install NodeJS from dist, as debian:jessie's nodejs is outdated for use with Phoenix:
RUN NODE_VERSION=5.0.0 \
 && set -ex \
 && for key in \
    9554F04D7259F04124DE6B476D5A82AC7E37093B \
    94AE36675C464D64BAFA68DD7434390BDBE9B9C5 \
    0034A06D9D9B0064CE8ADF6BF1747F4AD2306D93 \
    FD3A5288F042B6850C66B31F09FE44734EB7990E \
    71DCFD284A79C3B38668286BC97EC7A07EDE3FC1 \
    DD8F2338BAE7501E3DD5AC78C273792F7D83545D \
  ; do \
    gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
  done \
 && curl -SLO "https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION-linux-x64.tar.gz" \
 && curl -SLO "https://nodejs.org/dist/v$NODE_VERSION/SHASUMS256.txt.asc" \
 && gpg --verify SHASUMS256.txt.asc \
 && grep " node-v$NODE_VERSION-linux-x64.tar.gz\$" SHASUMS256.txt.asc | sha256sum -c - \
 && tar -xzf "node-v$NODE_VERSION-linux-x64.tar.gz" -C /usr/local --strip-components=1 \
 && rm "node-v$NODE_VERSION-linux-x64.tar.gz" SHASUMS256.txt.asc

# 4: Install postgres client used by ecto-postgres, and the inotify-tools:
RUN apt-get update \
 && apt-get install -y postgresql-client inotify-tools \
 && rm -rf /var/lib/apt/lists/*

EXPOSE 4000
CMD ["mix","phoenix.server"]

docker-compose.yml

---
# Our data container, mainly for storing the Postgres container's database
# files. This will allow us to move between postgres versions without losing the
# data currently in our development environment.

# We won't worry if this container is not in a "running state" when you
# type 'docker-compose ps'.
data:
  image: tianon/true
  volumes: [ "/var/lib/postgresql/data", "/app/tablas" ]

# Our PostgreSQL service:
postgres:
  image: postgres:9.4.5
  # Bind host port 5432 to PostgreSQL port 5432:
  ports: [ "5432:5432" ]
  # We're mounting 'db/dumps' into the postgres container so we can backup and
  # restore data dumps easily:
  volumes: [ "./priv/repo/dumps:/data-dumps" ]
  volumes_from: [ "data" ]
  environment:
    LC_ALL: C.UTF-8

# Web:
web:
  build: .
  dockerfile: development.Dockerfile
  volumes: [ ".:/usr/src/app" ]
  ports: [ "4000:4000" ]
  working_dir: /usr/src/app
  entrypoint: /usr/src/app/development-entrypoint.sh
  command: mix phoenix.server
  environment: &app_environment
    DATABASE_URL: postgres://postgres:h1ph03n1x@postgres.hi-phoenix.local:5432/hi_phoenix_dev?pool=25&encoding=unicode&schema_search_path=public
    PHO_ENV: development
  links:
    - postgres:postgres.hi-phoenix.local
  env_file: [] # [ "dev.env" ]