[stresstests] Support CSTRESS_BROKER and CSTRESS_PREFETCH envvars

funtests/stress/stress/app.py

@@ -12,14 +12,16 @@ from celery import Celery
 from celery.exceptions import SoftTimeLimitExceeded
 
 CSTRESS_QUEUE = os.environ.get('CSTRESS_QUEUE_NAME', 'c.stress')
+CSTRESS_BROKER = os.environ.get('CSTRESS_BROKER', 'amqp://')
 CSTRESS_BACKEND = os.environ.get('CSTRESS_BACKEND', 'redis://')
+CSTRESS_PREFETCH = int(os.environ.get('CSTRESS_PREFETCH', 1))
 
 app = Celery(
-    'stress', broker='amqp://', backend=CSTRESS_BACKEND,
+    'stress', broker=CSTRESS_BROKER, backend=CSTRESS_BACKEND,
     set_as_current=False,
 )
 app.conf.update(
-    CELERYD_PREFETCH_MULTIPLIER=1,
+    CELERYD_PREFETCH_MULTIPLIER=CSTRESS_PREFETCH,
     CELERY_DEFAULT_QUEUE=CSTRESS_QUEUE,
     CELERY_QUEUES=(
         Queue(CSTRESS_QUEUE,