Contents

require_relative('event_machine_driver')
module Wukong
  module Local

    # A class for driving processors over the STDIN/STDOUT protocol.
    class StdioDriver < EM::P::LineAndTextProtocol
      include EventMachineDriver
      include Processor::StdoutProcessor
      include Logging
      
      def self.start(label, settings = {})
        EM.attach($stdin, self, label, settings)
      end

      def post_init      
        self.class.add_signal_traps
        setup_dataflow
      end

      def receive_line line
        driver.send_through_dataflow(line)
      rescue => e
        error = Wukong::Error.new(e)
        EM.stop
        
        # We'd to *raise* `error` here and have it be handled by
        # Wukong::Runner.run but we are fighting with EventMachine.
        # It seems no matter what we do, EventMachine will swallow any
        # Exception raised here (including SystemExit) and exit the
        # Ruby process with a return code of 0.
        #
        # Instead we just log the message that *would* have gotten
        # logged by Wukong::Runner.run and leave it to EventMachine to
        # exit very unnaturally.
        log.error(error.message)
      end

      def unbind
        finalize_and_stop_dataflow
        EM.stop
      end
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
wukong-3.0.1	lib/wukong/local/stdio_driver.rb
wukong-3.0.0	lib/wukong/local/stdio_driver.rb