Harden Celery schedule parsing and startup safety

config/celery.py

@@ -1,9 +1,11 @@
+import logging
 import os
 from celery import Celery
 from celery.schedules import crontab
 from django.conf import settings
 
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "config.settings.development")
+logger = logging.getLogger(__name__)
 
 app = Celery("hoopscout")
 app.config_from_object("django.conf:settings", namespace="CELERY")
@@ -27,15 +29,25 @@ def _parse_cron_expression(expression: str) -> dict[str, str]:
 
 def build_periodic_schedule() -> dict:
     if not settings.INGESTION_SCHEDULE_ENABLED:
+        logger.info("Periodic ingestion schedule disabled by INGESTION_SCHEDULE_ENABLED=0.")
         return {}
 
-    schedule_kwargs = _parse_cron_expression(settings.INGESTION_SCHEDULE_CRON)
-    return {
-        "ingestion.scheduled_provider_sync": {
-            "task": "apps.ingestion.tasks.scheduled_provider_sync",
-            "schedule": crontab(**schedule_kwargs),
+    try:
+        schedule_kwargs = _parse_cron_expression(settings.INGESTION_SCHEDULE_CRON)
+        return {
+            "ingestion.scheduled_provider_sync": {
+                "task": "apps.ingestion.tasks.scheduled_provider_sync",
+                "schedule": crontab(**schedule_kwargs),
+            }
         }
-    }
+    except Exception as exc:  # noqa: BLE001
+        logger.error(
+            "Invalid periodic ingestion schedule config. Task disabled. "
+            "INGESTION_SCHEDULE_CRON=%r error=%s",
+            settings.INGESTION_SCHEDULE_CRON,
+            exc,
+        )
+        return {}
 
 
 app.conf.beat_schedule = build_periodic_schedule()