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• Killing python ffmpeg subprocess breaks cli output

  17 mars 2016, par JayLev

  I’m trying to execute a system command with subprocess and reading the output.

  But if the command takes more than 10 seconds I want to kill the subprocess.

  I’ve tried doing this in several ways.

  My last try was inspired by this post : http://stackoverflow.com/a/3326559/969208

  Example :

  import os
  
  import signal
  
  from subprocess import Popen, PIPE
  
  
  
  class Alarm(Exception):
  
      pass
  
  
  
  def alarm_handler(signum, frame):
  
      raise Alarm
  
  
  
  def pexec(args):
  
  
  
      p = Popen(args, stdout=PIPE, stderr=PIPE)
  
  
  
      signal.signal(signal.SIGALRM, alarm_handler)
  
      signal.alarm(10)
  
  
  
      stdout = stderr = ''
  
      try:
  
          stdout, stderr = p.communicate()
  
          signal.alarm(0)
  
      except Alarm:
  
          try:
  
              os.kill(p.pid, signal.SIGKILL)
  
          except:
  
              pass
  
  
  
      return (stdout, stderr)

  The problem is : After the program exits no chars are shown in the cli until I hit return. And hitting return will not give me a new line.

  I suppose this has something to do with the stdout and stderr pipe.

  I’ve tried flushing and reading from the pipe (p.stdout.flush())

  I’ve also tried with different Popen args, but might’ve missed something. Just thought I’d keep it simple here.

  I’m running this on a Debian server.

  Am I missing something here ?

  EDIT :

  It seems this is only the case when killing an ongoing ffmpeg process. If the ffmpeg process exits normally before 10 seconds, there is no problem at all.

  I’ve tried executing a couple of different command that take longer than 10 seconds, one who prints output, one who doesn’t and a ffmpeg command to check the integrity of a file.

  args = ['sleep', '12s'] # Works fine
  
  args = ['ls', '-R', '/var'] # Works fine, prints lots for a long time
  
  args = ['ffmpeg', '-v', '1', '-i', 'large_file.mov','-f', 'null', '-'] # Breaks cli output

  I believe ffmpeg prints using \r and prints everything on the strerr pipe. Can this be the cause ? Any ideas how to fix it ?

• Killing python ffmpeg subprocess breaks cli output

  27 septembre 2017, par JayLev

  I’m trying to execute a system command with subprocess and reading the output.

  But if the command takes more than 10 seconds I want to kill the subprocess.

  I’ve tried doing this in several ways.

  My last try was inspired by this post : https://stackoverflow.com/a/3326559/969208

  Example :

  import os
  
  import signal
  
  from subprocess import Popen, PIPE
  
  
  
  class Alarm(Exception):
  
      pass
  
  
  
  def alarm_handler(signum, frame):
  
      raise Alarm
  
  
  
  def pexec(args):
  
  
  
      p = Popen(args, stdout=PIPE, stderr=PIPE)
  
  
  
      signal.signal(signal.SIGALRM, alarm_handler)
  
      signal.alarm(10)
  
  
  
      stdout = stderr = ''
  
      try:
  
          stdout, stderr = p.communicate()
  
          signal.alarm(0)
  
      except Alarm:
  
          try:
  
              os.kill(p.pid, signal.SIGKILL)
  
          except:
  
              pass
  
  
  
      return (stdout, stderr)

  The problem is : After the program exits no chars are shown in the cli until I hit return. And hitting return will not give me a new line.

  I suppose this has something to do with the stdout and stderr pipe.

  I’ve tried flushing and reading from the pipe (p.stdout.flush())

  I’ve also tried with different Popen args, but might’ve missed something. Just thought I’d keep it simple here.

  I’m running this on a Debian server.

  Am I missing something here ?

  EDIT :

  It seems this is only the case when killing an ongoing ffmpeg process. If the ffmpeg process exits normally before 10 seconds, there is no problem at all.

  I’ve tried executing a couple of different command that take longer than 10 seconds, one who prints output, one who doesn’t and a ffmpeg command to check the integrity of a file.

  args = ['sleep', '12s'] # Works fine
  
  args = ['ls', '-R', '/var'] # Works fine, prints lots for a long time
  
  args = ['ffmpeg', '-v', '1', '-i', 'large_file.mov','-f', 'null', '-'] # Breaks cli output

  I believe ffmpeg prints using \r and prints everything on the strerr pipe. Can this be the cause ? Any ideas how to fix it ?

• Révision 93109 : Compat PHP7 (peut être pas encore suffisant).

  23 novembre 2015, par marcimat@rezo.net

  La structure foreach change de comportement et s’applique par défaut sur une copie du tableau passé.
  Si on modifie le tableau dans le foreach… bien celui d’origine n’est pas affecté. Pour retrouver
  le comportement d’avant dans ces cas là, il faut passer la valeur par référence.

  cf.
  https://wiki.php.net/rfc/php7_foreach
  http://php.net/manual/fr/migration70.incompatible.php