Deleting bulk data

#!/usr/bin/python

import logging
import os
from datetime import datetime, timedelta

import django

django.setup()

from posthog.models import Event, ElementGroup
from django.utils import timezone

max_age_days = int(os.getenv("POSTHOG_CLEANUP_OLDER_THAN_DAYS", 30))
step_size = int(os.getenv("POSTHOG_CLEANUP_BATCH_SIZE", 1000))
dry_run = True if os.getenv("POSTHOG_CLEANUP_DRY_RUN", "False").lower() in ["true", "yes", "1"] else False
logging.basicConfig(level=logging.INFO, format='%(asctime)s %(message)s', datefmt='%m/%d/%Y %H:%M:%S ')


def get_events_older_than(older_than):
    return Event.objects.filter(timestamp__lt=timezone.make_aware(datetime.now() - timedelta(older_than))).values_list(
        'pk', flat=True)


def get_non_referenced_event_groups():
    event_group_hashes = Event.objects.all().values_list('elements_hash', flat=True)
    return ElementGroup.objects.exclude(hash__in=list(event_group_hashes))


def delete_items(item_type, items):
    if dry_run:
        logging.info("Skipping delete of items in dry run mode...")
        return
    item_type.objects.filter(id__in=list(items)).delete()


def delete_items_batched(item_type, items, logging_indent=6 * " "):
    number_of_items = len(items)
    logging.info("%sDeleting %d items of type %s using batches of %d size:", logging_indent, number_of_items,
                 item_type.__name__, step_size)
    last_id = 0
    while last_id + step_size <= number_of_items:
        delete_items(item_type, items[last_id:last_id + step_size])
        logging.info("%s   %d%%", logging_indent, int(last_id / number_of_items * 100))
        last_id += step_size
    delete_items(item_type, items[last_id:])
    logging.info("%s   100%%", logging_indent)


if __name__ == "__main__":
    logging.info("Running cleanup of PostHog...")
    start_time = datetime.now()
    logging.info(" - Deleting all events older than %d days:", max_age_days)
    delete_items_batched(Event, get_events_older_than(max_age_days))
    logging.info(" - Deleting all elements and element groups not referenced by any event anymore:")
    delete_items_batched(ElementGroup, get_non_referenced_event_groups())
    logging.info("Cleanup finished, total duration: %s", datetime.now() - start_time)