Unicorn setup for local development environment and Heroku

unicorn_setup.md

Unicorn setup for local development environment and Heroku

More info can be found on Heroku: Deploying Rails Applications with Unicorn

1. Add unicorn, rack-timeout, and foreman to your 'Gemfile'.

    gem 'unicorn'
    gem 'rack-timeout'
    
    group :development do
      gem 'foreman'
    end
   

2. Run bundle install

3. Create Procfile at the root of the project and add the following line: web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb

4. Create unicorn config at 'config/unicorn.rb'

      # Example - https://devcenter.heroku.com/articles/rails-unicorn#config
      
      worker_processes ENV["RAILS_ENV"] == "development" ? 1 : Integer(ENV["WEB_CONCURRENCY"] || 2)
      timeout 60
      preload_app true
   
      before_fork do |server, worker|
          Signal.trap 'TERM' do
            puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
            Process.kill 'QUIT', Process.pid
          end
   
          defined?(ActiveRecord::Base) and
            ActiveRecord::Base.connection.disconnect!
       end
   
      after_fork do |server, worker|
          Signal.trap 'TERM' do
            puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
        end
   
        defined?(ActiveRecord::Base) and
          ActiveRecord::Base.establish_connection
      end
   

5. Set Rack::Timeout in 'config/initializers/timeout.rb'

    # Heroku recommends setting this value to a lower value than the 'timeout' in your unicorn config
    Rack::Timeout.timeout = 55 # in seconds
   

6. Create 'script/server' to start unicorn locally:

    #!/usr/bin/env ruby -w
    puts "Starting server..."
    exec "bundle exec foreman start"
   

   Note: to make script/server executable, type this in the terminal: chmod +x script/server