scheduler/runner-first-visits: Log number of first visits scheduled

Refs. swh/devel/swh-scheduler#4687

swh/scheduler/celery_backend/first_visits.py

@@ -40,7 +40,7 @@ def schedule_first_visits(backend: SchedulerInterface):
                 f"{lister.first_visits_queue_prefix}:{task_type.backend_name}"
             )
 
-        send_to_celery(
+        nb_first_visits = send_to_celery(
             backend,
             visit_type_to_queue=visit_type_to_queue,
             policy="first_visits_after_listing",
@@ -84,3 +84,5 @@ def schedule_first_visits(backend: SchedulerInterface):
             )
             lister.first_visits_scheduled_at = utcnow()
             backend.update_lister(lister)
+
+        return nb_first_visits

swh/scheduler/cli/admin.py

@@ -248,9 +248,10 @@ def runner_first_visits(ctx, period):
 
     try:
         while True:
-            logger.debug("Schedule first visits")
+            logger.debug("Schedule first visits...")
             try:
-                schedule_first_visits(scheduler)
+                nb_first_visits = schedule_first_visits(scheduler)
+                logger.info("Scheduled %s first visits", nb_first_visits)
             except ValueError:
                 logger.exception("Unexpected error in run_high_priority_first_visits()")
                 sentry_sdk.capture_exception()