Simple Form With Docker

A basic RoR app that uses: Docker Compose, Postgres, PGAdmin, Rspec, Simplecov, Brakeman, Devise, PaperTrail, SimpleForm, Pagy

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.

Prerequisites

Requires Docker installed on your environment.

Installing & Running

Installation uses Docker Compose:

docker-compose build
docker-compose up
docker-compose run web rails db:create

Stopping the App

docker-compose down

Testing

Testing with RSpec

Step-by-step of Development

Create the Rails App in a Docker Container

Prerequisite: Install Docker on your environment.
Modified instructions from: Docker Docs, Quickstart: Compose and Rails
Create a Dockerfile containing:

FROM ruby:2.5.3-alpine3.8
RUN apk update && apk add --update build-base postgresql-dev nodejs tzdata
RUN mkdir /SimpleFormWithDocker
WORKDIR /SimpleFormWithDocker
COPY Gemfile /SimpleFormWithDocker/Gemfile
COPY Gemfile.lock /SimpleFormWithDocker/Gemfile.lock
RUN bundle install
COPY . /SimpleFormWithDocker

And a Gemfile containing:

source 'https://rubygems.org'
gem 'rails', '~> 5.2.1'

Create an empty Gemfile.lock.
Finally, describe the 3 services - web, postgres and pgadmin by creating a docker-compose.yml containing:

version: '3'
services:
  postgres:
    container_name: postgres_container
    image: postgres
    environment:
      POSTGRES_USER: ${POSTGRES_USER:-postgres}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-postgres}
      PGDATA: /data/postgres
    volumes:
       - postgres:/data/postgres
    networks:
      - postgres
    restart: unless-stopped

  web:
    container_name: web_container
    build: .
    command: bundle exec rails s -p 3000 -b '0.0.0.0'
    volumes:
      - .:/SimpleFormWithDocker
    ports:
      - "3000:3000"
    depends_on:
      - postgres
    networks:
      - postgres

  pgadmin:
    container_name: pgadmin_container
    image: dpage/pgadmin4
    environment:
      PGADMIN_DEFAULT_EMAIL: ${PGADMIN_DEFAULT_EMAIL:-pgadmin4@pgadmin.org}
      PGADMIN_DEFAULT_PASSWORD: ${PGADMIN_DEFAULT_PASSWORD:-admin}
    volumes:
       - pgadmin:/root/.pgadmin
    ports:
      - "${PGADMIN_PORT:-5050}:80"
    networks:
      - postgres
    restart: unless-stopped

networks:
  postgres:
    driver: bridge

volumes:
    postgres:
    pgadmin:
    web:

Build the rails skeleton app with:

docker-compose run web rails new . --force --database=postgresql

This will update the Gemfile and we need to rebuild the docker file:

docker-compose build

Connect the database by replacing the contents of config/database.yml with:

default: &default
  adapter: postgresql
  encoding: unicode
  host: postgres
  username: postgres
  password: postgres
  pool: 5

development:
  <<: *default
  database: simpleformwithdocker_development

test:
  <<: *default
  database: simpleformwithdocker_test

Boot the web app with:

docker-compose up

View the web app at localhost:3000 but note the error that the development database doesn't exist.
Now create the database:

docker-compose run web rails db:create

Visit localhost:3000 and see the skeleton Rails app is running.
Note: To stop the app use docker-compose down and restart it with docker-compose up
Check PGAdmin is functional at localhost:5050 and login using the username and password in the docker-compose.yml

Add RSpec Testing Framework for TDD

Add to the Gemfile into the group :development, :test do:

# Testing framework
gem 'rspec-rails'

Re-build the container after updating Gemfile:

docker-compose build

Generate the RSpec configuration:

docker-compose run web rails generate rspec:install

Ensure the correct version of RSpec is used:

docker-compose run web bundle binstubs rspec-core

Create a new folder spec/features and 3 new files: create_survey_spec.rb, delete_survey_spec.rb and edit_survey_spec.rb.
Let's begin TDD by adding a test scenario to create_survey_spec.rb:

require "rails_helper"

RSpec.feature "Creating Survey" do
  scenario "A user creates a new survey" do
    visit "/"

    click_link "New Survey"
    fill_in "Title", with: "What is your fave Pokemon?"
    fill_in "Field 1", with: "Bulbasaur"
    fill_in "Field 2", with: "Squirtle"
    fill_in "Field 3", with: "Charmander"
    click_button "Create Survey"

    expect(page).to have_content("Survey has been created")
    expect(page.current_path).to eq(surveys_path)
  end
end

To ensure test code coverage we add to the Gemfile:

group :test do
  ...
  # Code coverage
  gem 'simplecov', require: false
end

We don't want to upload the coverage reports to Git, so add to .gitignore:

#Ignore coverage files
coverage/*

At the top of spec/spec_helper.rb:

require 'simplecov'
SimpleCov.start 'rails' do
  # These filters are excluded from results
  add_filter '/bin/'
  add_filter '/db/'
  add_filter '/spec/'
  add_filter '/test/'
  add_filter do |source_file|
    source_file.lines.count < 5
  end
end

Now when you run RSpec you will see the code coverage and generate a report in the coverage folder.
Let's use Brakeman for static analysis by adding to the Gemfile:

group :development do
  ...
  # Static security vulnerability analysis
  gem 'brakeman'
end

Now re-build:

docker-compose build

To run RSpec:

docker-compose run web rspec

To run Brakeman and store it's report in our coverage folder:

docker-compose run web brakeman -o coverage/brakeman_report

Authors

David Provest - LinkedIn

License

This project is licensed under the MIT License - see the LICENSE.md file for details