unicorn config example

unicorn_example.rb

APP_ROOT = "/home/developer/exchanger/current"

before_exec do |server|
  # Fixing gemfile not found error
  # stop, startしてる場合は不要
  # USR2 -> WINCH -> QUITで無停止でrestartしてる場合は必要  
  ENV['BUNDLE_GEMFILE'] = "#{APP_ROOT}/Gemfile"
end

before_fork do |server, worker|
  begin
    defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!
  rescue Exception => ex
    warn "error occured at before_fork worker nr:#{worker.nr} : #{ex.inspect}"
    warn ex.backtrace.join("\n")
  end
  
  # 公式より
  # Throttle the master from forking too quickly by sleeping.  Due
  # to the implementation of standard Unix signal handlers, this
  # helps (but does not completely) prevent identical, repeated signals
  # from being lost when the receiving process is busy.
  sleep 1
end

after_fork do |server, worker|
  # 公式より
  # if preload_app is true, then you may also want to check and
  # restart any other shared sockets/descriptors such as Memcached,
  # and Redis.  TokyoCabinet file handles are safe to reuse
  # between any number of forked children (assuming your kernel
  # correctly implements pread()/pwrite() system calls)
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection(Rails.application.config.database_configuration[Rails.env])
    if ActiveRecord::Base.respond_to? :connection_proxy
      ActiveRecord::Base.connection_proxy.instance_variable_get(:@shards).each { |k, v| v.clear_reloadable_connections! }
    end
  end
end