Using docker and docker-compose for Ruby on Rails development with PostgreSQL

README.md

Instructions

Setup Base file structure:

Create the directory that will contain your project:

mkdir my-new-app
cd my-new-app

Create 3 blank files:

touch Dockerfile
touch docker-compose.yml
touch entrypoint.sh

Then copy/paste the corresponding files below.

You may want to replace my_new_app by the name of your app in the file docker-compose.yml.

Build the containers

docker-compose build

Install rails

docker-compose run web bash
# you're now running a bash terminal inside the container
gem install rails
rails new -d postgresql .
exit
# you're now out of the container

Update webpack config file

In config/webpacker.yml replace the key development/dev_server/host with the value 0.0.0.0 (localhost is the default value and we don't want it).

Update database.yml file

Replace your default database.yml file with the one provided here.

Update gitignore

echo "/docker" >> .gitignore
echo "/bundle" >> .gitignore

Launch local stack

docker-compose up

Create database

docker-compose run web bundle exec rails db:create

database.yml

default: &default
  encoding: unicode
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  url: <%= ENV['DATABASE_URL'] %>

test:
  <<: *default
  url: <%= ENV['DATABASE_URL_TEST'] %>

production:
  <<: *default
  url: <%= ENV['DATABASE_URL'] %>

docker-compose.yml

version: "2"
services:
  web:
    build:
      context: .
      args:
        USER_ID: ${USER_ID:-1000}
        GROUP_ID: ${GROUP_ID:-1000}
    volumes:
      - .:/usr/src/app:rw
    environment:
      DATABASE_URL: postgresql://admin:admin-secret@postgresql:5432/my_new_app_development
      DATABASE_URL_TEST: postgresql://admin:admin-secret@postgresql:5432/my_new_app_test
      WEBPACKER_DEV_SERVER_HOST: 172.17.0.1
    links:
      - postgresql
      - webpack
    ports:
      - 3000:3000
    command: bundle exec rails server -b 0.0.0.0 -p 3000 -e development
    stdin_open: true
    tty: true
  webpack:
    build:
      context: .
      args:
        USER_ID: ${USER_ID:-1000}
        GROUP_ID: ${GROUP_ID:-1000}
    ports:
      - 3035:3035
    volumes:
      - ./:/usr/src/app
    command: ./bin/webpack-dev-server
    environment:
      WEBPACK_HOST: "172.17.0.1:3035"
  specs:
    build:
      context: .
      args:
        USER_ID: ${USER_ID:-1000}
        GROUP_ID: ${GROUP_ID:-1000}
    volumes:
      - ./:/usr/src/app/
    environment:
      DATABASE_URL_TEST: postgresql://admin:admin-secret@postgresql:5432/my_new_app_test
      RAILS_ENV: test
    links:
      - postgresql
    command: "tail -F /dev/null"
  postgresql:
    image: scalingo/postgresql:12.2.0-6
    ports:
      - 5432:5432
    environment:
      DB_USER_ID: 1000
    volumes:
      - ./docker/postgresql-data:/var/lib/postgresql:rw
    command: /postgresql

Dockerfile

FROM ruby:3.0.1

ARG USER_ID
ARG GROUP_ID

RUN addgroup --gid $GROUP_ID user
RUN adduser --disabled-password --gecos '' --uid $USER_ID --gid $GROUP_ID user

RUN apt-get update -qq

ENV GEM_HOME="/usr/src/app/bundle"
ENV PATH $GEM_HOME/bin:$GEM_HOME/gems/bin:$PATH

RUN apt-get update -qq

# PostgreSQL client lib
RUN apt-get install libpq-dev

# Install NodeJS
RUN apt-get install -y nodejs
# To install a specific NodeJS version, comment the line above and
# uncomment the lines below
# RUN apt-get install apt-transport-https
# ENV NODE_VERSION 14.16.1
# RUN cd /opt && \
#     curl -L "https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION-linux-x64.tar.xz" | tar -xJf - && \
#     mv -v node-v$NODE_VERSION-linux-x64 node
# ENV PATH /node_modules/.bin:/opt/node/bin:$PATH

# Install yarn
RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
RUN apt-get update -qq
RUN apt-get install -y yarn

WORKDIR /usr/src/app

# Add a script to be executed every time the container starts.
COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh

USER $USER_ID

ENTRYPOINT ["entrypoint.sh"]

entrypoint.sh

#!/bin/sh
set -e

if [ -f tmp/pids/server.pid ]; then
  rm tmp/pids/server.pid
fi

exec $@