Management command to set Repeater.max_workers.

corehq/motech/repeaters/management/commands/set_repeater_workers.py

@@ -0,0 +1,37 @@
+from django.conf import settings
+from django.core.management.base import BaseCommand
+
+from corehq.motech.repeaters.models import Repeater
+
+
+class Command(BaseCommand):
+    help = f"""
+    Sets Repeater.max_workers, which is the number of Celery workers
+    allocated to sending a batch of repeat records. Set to "0" to use
+    the default, which is {settings.DEFAULT_REPEATER_WORKERS}. Set to
+    "1" to send repeat records chronologically, one at a time. The
+    maximum value is {settings.MAX_REPEATER_WORKERS}.
+    """
+
+    def add_arguments(self, parser):
+        parser.add_argument('domain')
+        parser.add_argument('repeater_id')
+        parser.add_argument('max_workers', type=int)
+
+    def handle(self, domain, repeater_id, max_workers, *args, **options):
+        if not 0 <= max_workers <= settings.MAX_REPEATER_WORKERS:
+            self.stderr.write(
+                'max_workers must be between 0 and '
+                f'{settings.MAX_REPEATER_WORKERS}.'
+            )
+        # Use QuerySet.update() to avoid a race condition if the
+        # repeater is currently in use.
+        rows = (
+            Repeater.objects
+            .filter(domain=domain, id=repeater_id)
+            .update(max_workers=max_workers)
+        )
+        if not rows:
+            self.stderr.write(
+                f'Repeater {repeater_id} was not found in domain {domain}.'
+            )

settings.py

@@ -632,7 +632,7 @@
 # repeater can use to send repeat records at the same time. This is a
 # guardrail to prevent one repeater from hogging repeat_record_queue
 # workers and to ensure that repeaters are iterated fairly.
-MAX_REPEATER_WORKERS = 144
+MAX_REPEATER_WORKERS = 79
 
 # websockets config
 WEBSOCKET_URL = '/ws/'