Add clean_observers management commands

that cleans old subscriptions

docs/CHANGELOG.rst

@@ -15,6 +15,10 @@ Changed
 - Relation slug can be updated
 - Anonymous user can access the annotation field endpoint
 
+Added
+-----
+- Add ``clean_observers`` management command to clean old subsciptions
+
 
 ===================
 36.0.0 - 2023-07-17

resolwe/observers/management/__init__.py

@@ -0,0 +1,10 @@
+""".. Ignore pydocstyle D400.
+
+====================
+Observers Management
+====================
+
+.. automodule:: resolwe.observers.management.commands.register
+    :members:
+
+"""

resolwe/observers/management/commands/__init__.py

@@ -0,0 +1 @@
+"""Management commands module."""

resolwe/observers/management/commands/clean_observers.py

@@ -0,0 +1,54 @@
+""".. Ignore pydocstyle D400.
+
+=======================
+Clean old observer data
+=======================
+
+Command to run:
+
+    ./manage.py clean_observers
+
+"""
+import logging
+
+from django.core.management.base import BaseCommand
+from django.utils import timezone
+
+from resolwe.observers.models import Observer, Subscription
+
+# Delete subscriptions older than DELETE_OLDER_THAN hours.
+DELETE_OLDER_THAN = 5 * 24
+
+logger = logging.getLogger(__name__)
+
+
+class Command(BaseCommand):
+    """Delete old observers subscriptions."""
+
+    help = "Delete old observer subscriptions."
+
+    def add_arguments(self, parser):
+        """Command arguments."""
+        parser.add_argument(
+            "--older-than",
+            type=int,
+            dest="older_than",
+            help="Delete subscriptions older than older-than hours",
+        )
+
+    def handle(self, *args, **options):
+        """Delete old observer subscriptions."""
+        delete_older_than = options["older_than"] or DELETE_OLDER_THAN
+        logger.info(
+            "Deleting observer subscriptions older than %d hours.", delete_older_than
+        )
+        # Delete subscriptions older than delete_older_than hours.
+        deleted_subscriptions = Subscription.objects.filter(
+            created__lt=timezone.now() - timezone.timedelta(hours=delete_older_than)
+        ).delete()[0]
+        logger.info("Deleted %d subscriptions.", deleted_subscriptions)
+        # Delete observers without subscriptions.
+        deleted_observers = Observer.objects.filter(
+            subscriptions__isnull=True
+        ).delete()[0]
+        logger.info("Deleted %d observers.", deleted_observers)