🐳 Added code to provide health check for Celery.

src/open_inwoner/celery.py

@@ -1,7 +1,9 @@
+from pathlib import Path
+
 from django.conf import settings
 
-from celery import Celery
-from celery.signals import setup_logging
+from celery import Celery, bootsteps
+from celery.signals import setup_logging, worker_ready, worker_shutdown
 
 from .setup import setup_env
 
@@ -26,3 +28,45 @@ def config_loggers(*args, **kwargs):
     from logging.config import dictConfig
 
     dictConfig(settings.LOGGING)
+
+
+HEARTBEAT_FILE = Path(settings.BASE_DIR) / "tmp" / "celery_worker_heartbeat"
+READINESS_FILE = Path(settings.BASE_DIR) / "tmp" / "celery_worker_ready"
+
+
+#
+# Utilities for checking the health of celery workers
+#
+class LivenessProbe(bootsteps.StartStopStep):
+    requires = {"celery.worker.components:Timer"}
+
+    def __init__(self, worker, **kwargs):
+        self.requests = []
+        self.tref = None
+
+    def start(self, worker):
+        self.tref = worker.timer.call_repeatedly(
+            10.0,
+            self.update_heartbeat_file,
+            (worker,),
+            priority=10,
+        )
+
+    def stop(self, worker):
+        HEARTBEAT_FILE.unlink(missing_ok=True)
+
+    def update_heartbeat_file(self, worker):
+        HEARTBEAT_FILE.touch()
+
+
+@worker_ready.connect
+def worker_ready(**_):
+    READINESS_FILE.touch()
+
+
+@worker_shutdown.connect
+def worker_shutdown(**_):
+    READINESS_FILE.unlink(missing_ok=True)
+
+
+app.steps["worker"].add(LivenessProbe)