python - How to clean up after subprocess.Popen? -

i have long-running python script perl worker subprocess. data sent in , out of child proc through stdin , stdout. periodically, child must restarted.

unfortunately, after while of running, runs out of files ('too many open files'). lsof shows many remaining open pipes.

what's proper way clean after popen'd process? here's i'm doing right now:

def start_helper(self):     # spawn perl helper     cwd = os.path.dirname(__file__)     if not cwd:         cwd = '.'      self.subp = subprocess.popen(['perl', 'theperlthing.pl'], shell=false, cwd=cwd,                                  stdin=subprocess.pipe, stdout=subprocess.pipe,                                  bufsize=1, env=perl_env)  def restart_helper(self):     # clean     if self.subp.stdin:         self.subp.stdin.close()     if self.subp.stdout:         self.subp.stdout.close()     if self.subp.stderr:         self.subp.stderr.close()      # kill     try:         self.subp.kill()     except oserror:         # can't kill dead proc         pass     self.subp.wait() # ?      self.start_helper() 

i think that's need:

def restart_helper(self):     # kill process if open     try:         self.subp.kill()     except oserror:         # can't kill dead proc         pass      self.start_helper()     # wait comes after opened process     # if want know how process ended can add     # > if self.subp.wait() != 0:     # process exits 0 had no errors     self.subp.wait() 

as far know file objects closed before popen process gets killed.