[Python-Dev] Avoiding file descriptors leakage in subprocess.Popen()

Sat Jun 13 02:06:13 CEST 2009

Facundo Batista wrote:
> I just don't like a huge try/finally... but as FDs are just ints, do
> you think is there a better way to handle it?

How about a nice 'n shiny context wrapper for the pipe:
import os
class Pipe(object):
 def __enter__(self):
 self.read, self.write = os.pipe()
 return self.read, self.write
 def __exit__(self, *args):
 try:
 os.close(self.read)
 finally:
 # make sure that write is closed even if
 # self.read can't be closed
 os.close(self.write)
with Pipe() as (read, write):
 print read, write
Christian
PS and nit pick:
File descriptor are opaque resource handlers which just happened to be
ints. They should be treated as magic cookies.