Demonstration of how to create cron like periodic tasks using python RQ (http://python-rq.org/), django_rq (https://github.com/ui/django-rq), rq_scheduler (https://github.com/ui/rq-scheduler)

rqperiodic.py

# put in app/management/commands

from datetime import datetime
import importlib
import logging
from optparse import make_option

from django.conf import settings
from django.core.management.base import BaseCommand
import django_rq


logger = logging.getLogger(__name__)


def import_function(path):
    """
    Given the fully qualified path to the function, return that function.
    """
    # path should be of the form module.submodule...submodule.function
    # function name is the element after the last period
    function_name = path.split('.')[-1]
    # the module path is the full path minus the function_name and its leading
    # period.
    module_path = path[:-len(function_name)-1]
    lib = importlib.import_module(module_path)
    return lib.__getattribute__(function_name)


class Command(BaseCommand):
    """
    Runs RQ scheduler
    """
    help = __doc__

    option_list = BaseCommand.option_list + (
        make_option(
            '--verbose',
            dest='verbose',
            action="store_true",
            default=False,
            help="If True, it will print the list of scheduled tasks.",
        ),
        make_option(
            '--queue',
            dest='queue',
            default='default',
            help='Queue that scheduled tasks will be sent to.'
        )
    )

    def handle(self, task_module=None, *args, **options):
        verbose = options.get('verbose')
        queue = options.get('queue')

        scheduler = django_rq.get_scheduler(queue)

        # cancel any currently scheduled tasks that are listed in the
        # settings.
        func_names = [j['task'] for j in settings.RQ_PERIODIC]
        for j in scheduler.get_jobs():
            if j.func_name in func_names:
                j.cancel()

        for task in settings.RQ_PERIODIC:
            # grab the function path, remove it from the dictionary
            t = task.pop('task')

            # add the function object to the dictionary
            # and set repeat to None, the task will repeat forever.
            task.update({
                'func': import_function(t),
                'repeat': None
            })

            # add the task to the schedule
            scheduler.schedule(
                scheduled_time=datetime.now(),
                **task
            )

            # verbose logging
            if verbose:
                scheduled = scheduler.get_jobs()
                logger.info("Adding {} to scheduled tasks.".format(t))
                logger.info("Currently scheduled tasks ({}):\n {}".format(
                    len(scheduled),
                    '\n\t'.join([j.func_name for j in scheduled])
                ))

settings.py

# add the following to your django settings

# settings describing the tasks that should be run by the rqperiodc management
# command. A list of dicts of the form
# {
#    'task': fully qualified path to the task,
#    'args': list of arguments to pass to the task,
#    'kwargs': a dict of kwargs to pass,
#    'interval': seconds between runs,
#    'timeout': task timeout, use -1 to allow unlimited time,
#    'result_ttl': seconds the result is kept,
# }
RQ_PERIODIC = [
    {
        'task': 'app.my_hourly_task',
        'args': [],
        'kwargs': {},
        'interval': 3600,
        'timeout': -1,
        'result_ttl': 86400,
    },
    {
        'task': 'app.my_hourly_task_w_args',
        'args': [],
        'kwargs': {'name':'Bob'},
        'interval': 3600,
        'timeout': -1,
        'result_ttl': 86400,
    },
    
]

tasks.py

# I put all of my functions what will be run via RQ into a tasks.py folder, one per app.
from datetime import datetime
from django_rq import job


# use negative timeouts for unbound tasks.
@job('default', timeout=-1)
def my_hourly_task():
    print "This is a simple test", datetime.now()
    
    
@job('default')
def my_hourly_task_w_args(name=None):
    if name:
        print "{}'s hourly task".format(name)
    else:
        print "Another hourly task"