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

Christian Heimes lists at cheimes.de
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.

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