🚧 Add celery scripts to docker image

Author: SilviaAmAm

Dockerfile

@@ -66,6 +66,10 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 WORKDIR /app
 COPY ./backend/bin/docker_start.sh /start.sh
+COPY ./backend/bin/celery_worker.sh /celery_worker.sh
+COPY ./backend/bin/celery_beat.sh /celery_beat.sh
+COPY ./backend/bin/celery_flower.sh /celery_flower.sh
+COPY ./backend/bin/check_celery_worker_liveness.py /check_celery_worker_liveness.py
 
 RUN mkdir -p /app/log /app/media /app/src/openarchiefbeheer/static/
 

backend/Dockerfile

@@ -66,11 +66,13 @@ RUN apt-get update && apt-get upgrade -y && apt-get install -y --no-install-reco
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
+
 COPY ./bin/docker_start.sh /start.sh
-# Uncomment if you use celery
-# COPY ./bin/celery_worker.sh /celery_worker.sh
-# COPY ./bin/celery_beat.sh /celery_beat.sh
-# COPY ./bin/celery_flower.sh /celery_flower.sh
+COPY ./bin/celery_worker.sh /celery_worker.sh
+COPY ./bin/celery_beat.sh /celery_beat.sh
+COPY ./bin/celery_flower.sh /celery_flower.sh
+COPY ./bin/check_celery_worker_liveness.py /check_celery_worker_liveness.py
+
 RUN mkdir /app/bin /app/log /app/media
 
 VOLUME ["/app/log", "/app/media"]

backend/bin/check_celery_worker_liveness.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+#
+# Check the health of a Celery worker.
+#
+# The worker process writes and periodically touches a number of files that indicate it
+# is available and still healthy. If the worker becomes unhealthy for any reason, the
+# timestamp of when the heartbeat file was last touched will not update and the delta
+# becomes too big, allowing (container) orchestration to terminate and restart the
+# worker process.
+#
+# Example usage with Kubernetes, as a liveness probe:
+#
+# .. code-block:: yaml
+#
+#       livenessProbe:
+#         exec:
+#           command:
+#           - python
+#           - /app/bin/check_celery_worker_liveness.py
+#         initialDelaySeconds: 10
+#         periodSeconds: 30  # must be smaller than `MAX_WORKER_LIVENESS_DELTA`
+#
+# Reference: https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/#define-a-liveness-command
+#
+# Supported environment variables:
+#
+# * ``MAX_WORKER_LIVENESS_DELTA``: maximum delta between heartbeats before reporting
+#   failure, in seconds. Defaults to 60 (one minute).
+
+
+import os
+import sys
+import time
+from pathlib import Path
+
+HEARTBEAT_FILE = Path(__file__).parent.parent / "tmp" / "celery_worker_heartbeat"
+READINESS_FILE = Path(__file__).parent.parent / "tmp" / "celery_worker_ready"
+MAX_WORKER_LIVENESS_DELTA = int(os.getenv("MAX_WORKER_LIVENESS_DELTA", 60))  # seconds
+
+
+# check if worker is ready
+if not READINESS_FILE.is_file():
+    print("Celery worker not ready.")
+    sys.exit(1)
+
+# check if worker is live
+if not HEARTBEAT_FILE.is_file():
+    print("Celery worker heartbeat not found.")
+    sys.exit(1)
+
+# check if worker heartbeat satisfies constraint
+stats = HEARTBEAT_FILE.stat()
+worker_timestamp = stats.st_mtime
+current_timestamp = time.time()
+time_diff = current_timestamp - worker_timestamp
+
+if time_diff > MAX_WORKER_LIVENESS_DELTA:
+    print("Celery worker heartbeat: interval exceeds constraint (60s).")
+    sys.exit(1)
+
+print("Celery worker heartbeat found: OK.")
+sys.exit(0)