Question

I’m running Gitolite over the Git repository and I have post-receive hook there. The script of this hook written in Python and fails after

proc = subprocess.Popen('git log', shell = True, stdout=subprocess.PIPE)
out = proc.stdout.read()

It doesn’t execute after these lines. If I run this script manually, it works perfect.

What I’m doing wrong?

Answer 1

From subprocess documentation:

Warning

Use communicate() rather than .stdin.write, .stdout.read or
.stderr.read to avoid deadlocks due to any of the other OS pipe
buffers filling up and blocking the child process.

I’d avoid using shell=True if possible too (IMO it’s only useful if you wanna use shell built-ins and it’s platform/shell specific), and pass Popen command as a list, like ['git', 'log']

Try something like:

>>> proc = subprocess.Popen(['git', 'log'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
>>> proc.communicate()
('', 'fatal: Not a git repository (or any of the parent directories): .git\n')

communicate()[0] is stdout, communicate()[1] is stderr.