🔥 [#3049] -- delete beat/task to send e-mails

django-yubin now uses celery for queuing out of the box, so we no longer
need to simulate cron to actually send out the e-mails.

See https://django-yubin.readthedocs.io/en/latest/install.html\#upgrading-from-previous-versions
which documents the upgrade steps.

src/openforms/conf/base.py

@@ -349,7 +349,7 @@
 #
 # Sending EMAIL
 #
-EMAIL_BACKEND = "django_yubin.smtp_queue.EmailBackend"
+EMAIL_BACKEND = "django_yubin.backends.QueuedEmailBackend"
 EMAIL_HOST = config("EMAIL_HOST", default="localhost")
 EMAIL_PORT = config(
     "EMAIL_PORT", default=25
@@ -674,10 +674,6 @@
         # https://docs.celeryproject.org/en/v4.4.7/userguide/periodic-tasks.html#crontab-schedules
         "schedule": crontab(minute=0, hour=0),
     },
-    "send-emails": {
-        "task": "openforms.utils.tasks.send_emails",
-        "schedule": config("BEAT_SEND_EMAIL_INTERVAL", default=20),  # every 20 seconds
-    },
     "retry-submissions-processing": {
         "task": "openforms.submissions.tasks.retry_processing_submissions",
         "schedule": config("RETRY_SUBMISSIONS_INTERVAL", default=60 * 5),

src/openforms/utils/tasks.py

@@ -2,8 +2,6 @@
 
 from django.core import management
 
-from celery_once import QueueOnce
-
 from ..celery import app
 
 logger = logging.getLogger(__name__)
@@ -16,16 +14,6 @@ def clear_session_store():
     management.call_command("clearsessions")
 
 
-@app.task(
-    base=QueueOnce,
-    ignore_result=True,
-    once={"graceful": True},  # do not spam error monitoring
-)
-def send_emails() -> None:
-    logger.debug("Processing e-mail queue")
-    management.call_command("send_mail")
-
-
 @app.task(ignore_result=True)
 def cleanup_csp_reports() -> None:
     logger.debug("Cleanup CSP reports")