Module: Collective::Utilities::Process

Extended by:
Process
Included in:
Process
Defined in:
lib/collective/utilities/process.rb

Instance Method Summary collapse

Instance Method Details

#alive?(pid) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/collective/utilities/process.rb', line 74

def alive?( pid )
  !! ::Process.kill( 0, pid )
rescue Errno::ESRCH
  false
end

#fork_and_detach(options = {}, &action) ⇒ Object 



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# File 'lib/collective/utilities/process.rb', line 39

def fork_and_detach( options = {}, &action)
  # Fork twice. First child doesn't matter. The second is our favorite.
  pid1 = fork do
    ::Process.setsid
    exit if fork
    redirect_stdio( options[:stdout] )
    action.call
  end

  # We must call waitpid on the first child to keep it from turning into a zombie
  ::Process.waitpid(pid1)
end

#redirect_stdio(stdout) ⇒ Object 



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# File 'lib/collective/utilities/process.rb', line 60

def redirect_stdio( stdout )
  STDIN.reopen "/dev/null"
  if stdout then
    mask = File.umask(0000)
    file = File.new( stdout, "a" ) # append or create, write only
    File.umask( mask )
    STDOUT.reopen( file )
  else
    STDOUT.reopen "/dev/null"
  end
  STDERR.reopen(STDOUT)
end

#wait2_now(pid) ⇒ Object 



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# File 'lib/collective/utilities/process.rb', line 53

def wait2_now( pid )
  ::Process.wait2( pid, ::Process::WNOHANG )
rescue Errno::ECHILD # No child processes
  return [ nil, 0 ]
end

#wait_and_terminate(pid, options = {}) ⇒ Object 



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# File 'lib/collective/utilities/process.rb', line 19

def wait_and_terminate( pid, options = {} )
  #log "Monitoring job #{pid}"
  timeout = options[:timeout] || 1024
  signal  = options[:signal] || "TERM"
  
  status = wait_until_deadline( pid, Time.now.to_f + timeout )
  return status if status
  
  #log "Job #{pid} is overdue, killing"
  
  ::Process.kill( signal, pid )
  status = wait_until_deadline( pid, Time.now.to_f + 1 )
  return status if status
  
  ::Process.kill( "KILL", pid ) if ! status
  dummy, status = wait2_now(pid)
  status
end

#wait_until_deadline(pid, deadline) ⇒ Object 



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# File 'lib/collective/utilities/process.rb', line 5

def wait_until_deadline( pid, deadline )
  status   = nil
  interval = 0.125
  begin # execute at least once to get status
    dummy, status = wait2_now(pid)
    break if status
    #log "Waiting for #{pid}", "Sleeping #{interval}" if false
    sleep(interval)
    interval *= 2 if interval < 1.0
  end while Time.now.to_f < deadline
  status
end