service_haproxy_handler.rb

module OurService
  def run_thrift_server
    handler   = TcUser::Thrift::UserServiceHandler.new
    processor = TcUser::Thrift::UserService::Processor.new(handler)
    transport = ::Thrift::ServerSocket.new(port)
    t_factory = ::Thrift::BufferedTransportFactory.new

    @server = ::Thrift::MutexableThreadPoolServer.new(processor, transport, t_factory, nil, {:num => 20, :mutex => mutex})

    info "Service '#{name}' started with Process ID #{$$}"
    zookeeper_connect

    info "Writing PID to #{pid_file}..."
    write_pid!
    handle_signals!
    info "Done."

    info "Starting the #{TcUser::Thrift.name} server on port #{port}..."

    info "Running Serve Loop..."
    @server.serve {
      info "Serve Callback Called. Enabling HAProxy..."
      enable_haproxy!
    }

    info "Done?"
  end

  def handle_signals!
    %w{INT TERM USR1}.each do |sig|
      ::Signal.trap(sig) {
        info "received signal #{sig}. Stopping..."

        disable_haproxy!        # Tell HAProxy to stop sending traffic.

        info "Locking Mutex..." # Lock the Mutex, so the threads eventually die.
        mutex.lock

        # Give them 60 seconds to seppuku.
        Thread.new do
          info "Sleeping for 60-seconds, before hard exit."
          sleep(60)

          info "!! Done sleeping..."
          info "!! Begin hard exit... Deleting PID..."
          delete_pid!

          info "!! Hard Exiting."
          exit!
        end

        info "Stopping threads."  # Exit early if they end before those 60-seconds. This is how it *should* happen.
        @server.stop_threads

        info "Deleting PID..."
        delete_pid!

        info "Exiting..."
        # Bye.
        exit!
      }
    end
  end

  def enable_haproxy!
    shell_command = %{echo "enable server tc-user/#{name}" | socat unix-connect:/tmp/proxystats stdio}
    response = `#{shell_command}`
    return(true) if response == "\n"
    raise RuntimeError, "Failed to enable HAProxy. Received the message #{response}"
  end

  def disable_haproxy!
    shell_command = %{echo "disable server tc-user/#{name}" | socat unix-connect:/tmp/proxystats stdio}
    `#{shell_command}` == "\n"
  end
end