Docker & Docker Compose for Ruby on Rails

docker-compose.yml

services:
  db:
    image: postgres:15.2-alpine # or define exact version, postgres:14
    container_name: the_office_db
    ports:
      - "5432:5432"
    environment:
      - POSTGRES_DB=the_office_db
      - POSTGRES_USER=db_user
      - POSTGRES_PASSWORD=super_secure_password # change to secure password
    volumes:
      - pg_data:/var/lib/postgresql/data # where we will store data      
  redis:
    image: redis:7.0.8-alpine # or define exact version, redis:6
    container_name: the_office_redis
    volumes:
      - redis_data:/data # where we will store data    
  app:
    container_name: the_office_app
    build: .
    # command: bin/rails s -b "0.0.0.0"
    command: bin/dev
    ports:
      - "3000:3000"
    stdin_open: true
    tty: true      
    environment:
      - HISTFILE=/app/log/.bash_history 
      - DATABASE_URL=postgresql://db_user:super_secure_password@db
      - REDIS_URL=redis://redis:6379
      - DOCKER=true
      - HOST=localhost:3000
      - SITE=localhost
      - EMAIL=no-reply@yourmail.com
      - NAME=Name of you app
    depends_on:
      - db
      - redis
    volumes:
      - .:/app
      - bundle:/gems
    tmpfs:  
      # Use temporary file system, instead of manually removing files through `bash -c "rm -f tmp/pids/server.pid"`
      - /tmp
      - /app/tmp/pids
volumes:
  pg_data:
  redis_data:
  bundle:

docker-entrypoint.sh

#!/bin/bash
set -e

# Remove a potentially pre-existing server.pid for Rails.
echo "Remove a potentially pre-existing server.pid for Rails..."
rm -f /usr/src/app/tmp/pids/server.pid

echo "Run bundle install..."
bundle check || bundle install --jobs 4

# Then exec the container's main process (what's set as CMD in the Dockerfile).
exec "$@"

Dockerfile

ARG RUBY_VERSION=3.2.1
FROM ruby:$RUBY_VERSION-slim

# Install essentials for running gems and app
RUN apt-get update -qq && apt-get install -yq --no-install-recommends \
    build-essential \
    postgresql-client \
    gnupg2 \
    less \
    git \
    git-core \
    curl \ 
    libssl-dev \
    libreadline-dev \
    libyaml-dev \
    libsqlite3-dev \
    libpq-dev \
    libcurl4-openssl-dev \
    postgresql-client \
    libffi-dev \ 
    libvips \
    imagemagick \ 
    dirmngr \
    tzdata \
    vim-tiny \
    && apt-get clean autoclean \
    && apt-get autoremove -y \
    && rm -rf \
    /var/lib/apt \
    /var/lib/dpkg \
    /var/lib/cache \
    /var/lib/log \
    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

# Update Gems and install Bundler
RUN gem update --system
RUN gem install bundler

# Add Bundle to $PATH
ENV BUNDLE_PATH /gems
ENV LANG=C.UTF-8 \
    BUNDLE_JOBS=4 \
    BUNDLE_RETRY=3

# Setup workdir and copy code from local machine to container working directory
WORKDIR /app
COPY . /app/

# Copy Gemfile to container
COPY Gemfile Gemfile.lock /app/

ENTRYPOINT ["./bin/docker-entrypoint.sh"]

CMD ["bundle", "exec", "rails", "s", "-b", "0.0.0.0", "-p", "3000"]

# Expose port to defined
EXPOSE 3000

dockerignore

.git
.git/
.gitignore

#
# OS X
#
.DS_Store
.AppleDouble
.LSOverride
# Icon must end with two \r
Icon
# Thumbnails
._*
# Files that might appear on external disk
.Spotlight-V100
.Trashes
# Directories potentially created on remote AFP share
.AppleDB
.AppleDesktop
Network Trash Folder
Temporary Items
.apdisk

#
# Rails
#
.env
.env.sample
*.rbc
capybara-*.html
.rspec
log
tmp
db/*.sqlite3
db/*.sqlite3-journal
public/system
coverage/
spec/tmp
**.orig
rerun.txt
pickle-email-*.html
db/*.sqlite3
db/*.sqlite3-journal
.rvmrc
.byebug_history
node_modules
yarn-error.log

# if using bower-rails ignore default bower_components path bower.json files
vendor/assets/bower_components
*.bowerrc
bower.json