Unicorn + Octopus on Heroku

unicorn.rb

worker_processes Integer(ENV["WEB_CONCURRENCY"] || 4)
timeout 15
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

  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.connection_proxy.instance_variable_get(:@shards).each do |shard, connection_pool|
      connection_pool.disconnect!
    end

    ActiveRecord::Base.connection.disconnect!
  end
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

  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
    ActiveRecord::Base.connection_proxy.instance_variable_get(:@shards).each {|k,v| v.clear_reloadable_connections! }
  end

  Octopus.config['production']['master'] = ActiveRecord::Base.connection.config
  ActiveRecord::Base.connection.initialize_shards(Octopus.config)
end