Adding extra logging to celery tasks ans gunicorn, specifically log on SIGTERM and SIGINIT so that we can track better when an app restarts and why it restarts e.g. when it restarts after another signal.

app/celery/tasks.py

@@ -2,6 +2,7 @@ import json
 from datetime import (datetime)
 from collections import namedtuple
 
+from celery.signals import worker_process_init, worker_process_shutdown
 from flask import current_app
 from notifications_utils.recipients import (
     RecipientCSV
@@ -56,6 +57,11 @@ from app.statsd_decorators import statsd
 from notifications_utils.s3 import s3upload
 
 
+@worker_process_shutdown.connect
+def worker_process_shutdown(sender, signal, pid, exitcode):
+    current_app.logger.info('Tasks worker shutdown: PID: {} Exitcode: {}'.format(pid, exitcode))
+
+
 @notify_celery.task(name="process-job")
 @statsd(namespace="tasks")
 def process_job(job_id):