Method: ExecApp#initialize

Defined in:
lib/omf_common/exec_app.rb

#initialize(id, cmd, map_std_err_to_out = false, working_directory = nil, &observer) ⇒ ExecApp

Run an application ‘cmd’ in a separate thread and monitor its stdout. Also send status reports to the ‘observer’ by calling its “call(eventType, appId, message”)“

Parameters:

  • id —

    ID of application (used for reporting)

  • observer —

    Observer of application’s progress

  • cmd —

    Command path and args

  • map_std_err_to_out (defaults to: false) —

    If true report stderr as stdin [false]



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# File 'lib/omf_common/exec_app.rb', line 92

def initialize(id, cmd, map_std_err_to_out = false, working_directory = nil, &observer)

  @id = id || self.object_id
  @observer = observer
  @@all_apps[@id] = self
  @exit_status = nil
  @threads = []

  pw = IO::pipe   # pipe[0] for read, pipe[1] for write
  pr = IO::pipe
  pe = IO::pipe

  logger.debug "Starting application '#{@id}' - cmd: '#{cmd}'"
  #@observer.call(:STARTED, id, cmd)
  call_observer(:STARTED, cmd)
  @pid = fork {
    # child will remap pipes to std and exec cmd
    pw[1].close
    STDIN.reopen(pw[0])
    pw[0].close

    pr[0].close
    STDOUT.reopen(pr[1])
    pr[1].close

    pe[0].close
    STDERR.reopen(pe[1])
    pe[1].close

    begin
      pgid = Process.setsid # Create a new process group
                            # which includes all potential child processes
      STDOUT.puts "INTERNAL WARNING: Assuming process_group_id == pid" unless pgid == $$
      Dir.chdir working_directory if working_directory
      exec(cmd)
    rescue => ex
      cmd = cmd.join(' ') if cmd.kind_of?(Array)
      STDERR.puts "exec failed for '#{cmd}' (#{$!}): #{ex}"
    end
    # Should never get here
    exit!
  }

  pw[0].close
  pr[1].close
  pe[1].close
  monitor_pipe(:stdout, pr[0])
  monitor_pipe(map_std_err_to_out ? :stdout : :stderr, pe[0])
  # Create thread which waits for application to exit
  @threads << Thread.new(id, @pid) do |id, pid|
    Process.waitpid(pid)
    # Exit status is sometimes nil (OSX 10.8, ping)
    @exit_status = $?.exitstatus || 0
    if @exit_status > 127
      @exit_status = 128 - @exit_status
    end
    @@all_apps.delete(@id)
    # app finished
    if (@exit_status == 0) || @clean_exit
      logger.debug "Application '#{@id}' finished"
    else
      logger.debug "Application '#{@id}' failed (code=#{@exit_status})"
    end
  end
  @stdin = pw[1]

  # wait for done in yet another thread
  Thread.new do
    @threads.each {|t| t.join }
    call_observer("EXIT", @exit_status)
  end
  logger.debug "Application is running with PID #{@pid}"
end