docker Rails + postgres

README.md

Criar cada arquivo + Gemfile.lock - config/database.yml

docker-compose build

docker-compose run web rails new . --force --no-deps --database=postgresql

Substitui o config/database.yml criado pelo que está descrito aqui

docker-compose up

docker-compose exec web bash

database.yml

default: &default
  adapter:  postgresql
  host:     <%= ENV["POSTGRES_HOST"] %>
  encoding: unicode
  pool:     5
  username: <%= ENV["POSTGRES_USER"] %>
  password: <%= ENV["POSTGRES_PASSWORD"] %>
  template: template0

development:
  <<: *default
  database: myapp_development

test:
  <<: *default
  database: myapp_test

production:
  <<: *default
  database: myapp_production
  password: <%= ENV["POSTGRES_PASSWORD_PRODUCTION"] %>

docker-compose.yml

version: '3.7'
services:
  db_pg:
    image: postgres:12.6
    volumes:
      - postgres:/var/lib/postgresql/data
    env_file: .env
    ports:
      - "5433:5432"

  app:
    build: .
    depends_on:
      - db_pg
    ports:
      - "3000:3000"
    volumes:
      - .:/myapp
    env_file: .env
    command: bash -c "sleep 100000"

volumes:
  postgres:

Dockerfile

FROM ruby:2.7.2

RUN apt-get update -yqq && apt-get install -y build-essential libpq-dev nodejs

## install yarn
RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - \
    && echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
    && apt-get update && apt-get install -y yarn && rm -rf /var/lib/apt/lists/*

RUN mkdir /myapp
WORKDIR /myapp
COPY Gemfile /myapp/Gemfile
COPY Gemfile.lock /myapp/Gemfile.lock

##
RUN gem install bundler:2.0.2
RUN bundle check || bundle install
COPY . /myapp

## Add Endpoint
COPY docker-entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/docker-entrypoint.sh
ENTRYPOINT ["docker-entrypoint.sh"]
# EXPOSE 3000

entrypoint.sh

#!/bin/bash
set -e

rm -f tmp/pids/server.pid

bundle check || bundle install

yarn install

exec "$@"

Gemfile

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

gem 'rails', '~> 6.0.2'