Executing python subprocess via git hook

Question

I'm running Gitolite over the Git repository and I have post-receive hook there written in Python. I need to execute "git" command at git repository directory. There are few lines of code:

proc = subprocess.Popen(['git', 'log', '-n1'], cwd='/home/git/repos/testing.git' stdout=subprocess.PIPE, stderr=subprocess.PIPE)
proc.communicate()

After I make new commit and push to repository, scripts executes and says

fatal: Not a git repository: '.'

If I run

proc = subprocess.Popen(['pwd'], cwd='/home/git/repos/testing.git' stdout=subprocess.PIPE, stderr=subprocess.PIPE)

it says, as expected, correct path to git repository (/home/git/repos/testing.git)

If I run this script manually from bash, it works correct and show correct output of "git log". What I'm doing wrong?

Answer 1

There is a comma missing after the cwd argument:

proc = subprocess.Popen(['git', 'log', '-n1'], cwd='/home/git/repos/testing.git', stdout=subprocess.PIPE, stderr=subprocess.PIPE)

Answer 2

You could try to set the git repository using a command-line switch:

proc = subprocess.Popen(['git', '--git-dir', '/home/git/repos/testing.git', 'log', '-n1'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)

--git-dir needs to point to an actual git directory (.git in a working tree). Note that for some commands you also need to set a --work-tree option too.

Another way to set the directory is using the GIT_DIR environment variable:

import os
env = os.environ.copy()
env['GIT_DIR'] = '/home/git/repos/testing.git'
proc = subprocess.Popen((['git', 'log', '-n1', stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env)

Apparently hooks already set GIT_DIR but obviously this is incorrect for your case (it could be relative); the above code sets it to a full, explicit path.

See the git manpage.

Edit: Apparently it only works for the OP when specifying both a cwd and overriding the GIT_DIR var:

import os
repo = '/home/git/repos/testing.git'
env = os.environ.copy()
env['GIT_DIR'] = repo
proc = subprocess.Popen((['git', 'log', '-n1', stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env, cwd=repo)