Send mail to admins if celery tasks fail

aleksis/core/celery.py

 import os
 
+from django.conf import settings
+
 from celery import Celery
+from celery.signals import task_failure
+from templated_email import send_templated_mail
+
+from .util.core_helpers import get_site_preferences
 
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "aleksis.core.settings")
 
 app = Celery("aleksis")  # noqa
 app.config_from_object("django.conf:settings", namespace="CELERY")
 app.autodiscover_tasks()
+
+
+@task_failure.connect
+def task_failure_notifier(
+    sender=None, task_id=None, exception=None, args=None, traceback=None, **kwargs
+):
+    recipient_list = [e[1] for e in settings.ADMINS]
+    send_templated_mail(
+        template_name="celery_failure",
+        from_email=get_site_preferences()["mail__address"],
+        recipient_list=recipient_list,
+        context={
+            "task_name": sender.name,
+            "task": str(sender),
+            "task_id": str(task_id),
+            "exception": str(exception),
+            "args": str(args),
+            "kwargs": str(kwargs),
+            "traceback": str(traceback),
+        },
+    )