Auto-pull from a gitlab server everytime there is a push to your branch

gitlab_autopull.php

<?php

define('REMOTE', '199.198.197.196'); # gitlab server
define('BRANCH', 'development');
define('USER', 'remote_user'); # remote user with SSH keys to gitlab

openlog('gitlab', LOG_PID | LOG_ODELAY, LOG_LOCAL1);

if ($_SERVER['REMOTE_ADDR'] != REMOTE) {
  syslog(LOG_NOTICE, 'Calling wrong git server ' . $_SERVER['REMOTE_ADDR']);
}

$data = json_decode(file_get_contents('php://input'));

if ($data->ref == 'refs/heads/' . BRANCH) {
  $out = shell_exec('/usr/bin/sudo -u ' . USER . ' /usr/bin/git pull');
  syslog(LOG_NOTICE, $out);
} else {
  syslog(LOG_NOTICE, $data->ref);
}

closelog();

You need to add this line to the /etc/sudoers file:

www-data ALL=(ALL) NOPASSWD: /usr/bin/git pull