Class: ProcessWatcher::ProcessMonitor

Inherits:
Object
  • Object
show all
Includes:
Windows::Handle, Windows::Process, Windows::Synchronize
Defined in:
lib/process_watcher/linux/process_monitor.rb,
lib/process_watcher/win32/process_monitor.rb

Overview

Windows specific watcher implementation

Defined Under Namespace

Classes: Status

Instance Method Summary collapse

Instance Method Details

#cleanup ⇒ Object

Cleanup underlying handle

Return

true

Always return true



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# File 'lib/process_watcher/linux/process_monitor.rb', line 96

def cleanup
  @reader.join if @reader
  @io.close if @io && !@io.closed?
end

#spawn(cmd, *args) ⇒ Object

Spawn given process and callback given block with output and exit code

Parameters

cmd(String)

Process command line (including arguments)

arg1(String)

Optional, first command-line argumument

arg2(String)

Optional, first command-line argumument

…

argN(String)

Optional, Nth command-line argumument

Block

Given block should take one argument which is a hash which may contain the keys :output and :exit_code. The value associated with :output is a chunk of output while the value associated with :exit_code is the process exit code This block won’t be called anymore once the :exit_code key has associated value

Return

pid(Integer)

Spawned process pid



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# File 'lib/process_watcher/linux/process_monitor.rb', line 46

def spawn(cmd, *args)
  args = args.map { |a| a.to_s } #exec only likes string arguments

  #Run subprocess; capture its output using a pipe
  pr, pw = IO::pipe
  @pid = fork do
    oldstderr = STDERR.clone
    pr.close
    STDIN.close
    STDOUT.reopen(pw)
    STDERR.reopen(pw)
    begin
      exec(cmd, *args)
    rescue
      oldstderr.puts "Couldn't exec: #{$!}"
    end
  end

  #Monitor subprocess output and status in a dedicated thread
  pw.close
  @io = pr
  @reader = Thread.new do
    status = nil
    loop do
      status = Process.waitpid(@pid, Process::WNOHANG)
      break unless $?.nil?
      array = select([@io], nil, [@io], 0.1)
      array[0].each do |fdes|
        unless fdes.eof?
          # HACK HACK HACK 4096 is a magic number I pulled out of my
          # ass, the real one should depend on the kernel's buffer
          # sizes.
          result = fdes.readpartial(4096)
          yield(:output => result) if block_given?
        end
      end unless array.nil?
      array[2].each do |fdes|
        # Do something with erroneous condition.
      end unless array.nil?
    end
    yield(:exit_code => $?.exitstatus, :exit_status => $?) if block_given?
  end

  return @pid
end