[PYTHON] Django Management Command Duplicate Launch Decorator

decorators.py

def find_process_ids(pattern):
    """
Finds and returns the process ID that matches the pattern(Other than your own)
    :rtype: list
    """
    self_pid = os.getpid()
    try:
        out = subprocess.check_output(['pgrep', '-f', pattern])
        return list(filter(
            lambda x: x != self_pid, map(int, out.splitlines())))
    except subprocess.CalledProcessError:
        return []


def runs_once(batch_name):
    """
Preventing duplicate activation of management commands
    @runs_once(__file__)
    def handle(...):
        ...
    """
    re_batch_name = re.compile(r'^/.*/(\w+)\.py$')
    m = re_batch_name.match(batch_name)
    if m:
        batch_name = m.group(1)

    def _inner(func):
        @wraps(func)
        def decorate(*args, **kwargs):
            process_ids = find_process_ids(batch_name)
            if process_ids:
                print('process already exists. {}, {}'.format(
                    batch_name, process_ids)
                )
                return
            else:
                return func(*args, **kwargs)

        return decorate

    return _inner