Git post-receive hook sample for basic Django project

post-receive

#!/usr/bin/env python
#
# No Rights Reserved
# http://creativecommons.org/publicdomain/zero/1.0/
"""Git post-receive hook script

Suggested project structure::

    /home/$_USER/
        env/
            $_PROJECT/
                { venv named after project }
                bin/
                    activate
                    python
                    ...
        remote/
            { git bare repo }
        work/
            $_PROJECT/
                { project code }
                www/
                    { served as static content }
            settings.env
            settings.sample
            setup.py
            manage.py
        var/
            log/
                { dir for logs }
            www -> /home/$_USER/work/$_PROJECT/www

Note: '->' means symbolic link, created via `ln -s`

Database server is PostgreSQL and the database is in UTF-8 encoding
and named after $_PROJECT.
"""
import os

HOME = os.path.expanduser('~')
PYTHON = HOME + '/env/$_PROJECT/bin/python'
GIT_BRANCH = 'master'
WORK_DIR = HOME + '/work'
VAR_DIR = HOME + '/var'
DATABASE = '$_PROJECT'
RESTART_COMMAND = 'pkill -f /$_PROJECT/bin/waitress-serve' # For Waitress
# RESTART_COMMAND = 'pkill -f /$_PROJECT/bin/uwsgi' # For uWSGI

def hook(from_commit, to_commit, branch):
    """Handle post-receive hook.
    """
    git_require_branch(branch, GIT_BRANCH)

    db_create(DATABASE)

    makedirs(WORK_DIR)

    makedirs(VAR_DIR + '/log')

    git_checkout(WORK_DIR, branch)

    with cd(VAR_DIR):
        linkdirs([WORK_DIR + '/$_PROJECT/www', '.'])

    with cd(WORK_DIR):
        run(PYTHON + ' setup.py develop')
        run(PYTHON + ' manage.py migrate')
        run(PYTHON + ' manage.py collectstatic --noinput')
        run(PYTHON + ' manage.py compilemessages')

    run(RESTART_COMMAND)


###########
# Helpers #
###########

import sys
import logging
from subprocess import call
from contextlib import contextmanager

def makedirs(path, mode=0o755):
    try:
        os.makedirs(path, mode=mode)
        echo("CREATE PATH: %s" % path)
    except OSError:
        pass

def linkdirs(*links):
    """Add symlinks, `links` is a list of 2-tuples (from, to).
    """
    for l in links:
        path, to = l[0], l[1]
        makedirs(to)
        run('ln -s %s %s' % (path, to), ignore_fail=True)

def venv(path):
    """Create Python env via pyvenv-3.5 command line tool.
    """
    makedirs(os.path.dirname(path))
    if not os.path.exists(path):
        run('pyvenv-3.5 %s' % path)

def run(cmd, ignore_fail=False):
    """Run shell command and check for result. If not 0 then exit.
    """
    if not cmd:
        return 0
    echo("RUN: %s" % cmd)
    result = call(cmd, shell=True)
    if result > 0:
        if ignore_fail:
            echo("IGNORE: exit code %s" % result)
        else:
            echo("ERROR: exit code %s" % result)
            sys.exit(result)
    return result

@contextmanager
def cd(path):
    """Change current working directory and restore on exit, context manager.

    Usage:

        with cd(/my/path):
            run('my_command')
    """
    old_path = os.getcwd()
    os.chdir(path)
    yield
    os.chdir(old_path)

def git_checkout(to_path, branch='master'):
    """Perform git checkout call.
    """
    run('GIT_WORK_TREE="%s" git checkout -f %s' % (to_path, branch))

def git_require_branch(branch, check_branch):
    """Check branch name or exit.
    """
    if not branch.endswith(check_branch):
        echo("Received branch %s, not matching %s." %
            (branch, check_branch))
        sys.exit(1)

def db_create(db):
    """Try create database. Ignore fail.
    """
    if run('psql -c ";" %s' % db, ignore_fail=True):
        run('createdb -E utf-8 %s' % db)

def get_console():
    """Setup stdout logger and return function to print messages
    via logging.info().
    """
    console = logging.getLogger('console')
    console.setLevel(logging.DEBUG)
    ch = logging.StreamHandler()
    console.addHandler(ch)

    def echo(message, *args):
        more = ' '.join(map(str, args)) if args else ''
        console.info(message + more)

    return echo

echo = get_console() # Use echo() instead of print()

########
# Run! #
########

if __name__ == '__main__':
    # Read values from stdin: from commit, to commit, branch name
    args = sys.stdin.read().split()
    hook(*args)