fix: remove local Kafka settings

This commit removes Django settings from the local settings file, used by the local application server, related to setting up the Kafka implementation of the event bus. This is because the event bus does not work outside of a Docker container. This is because the event bus is run through the devstack networking layer, which is inaccessible by the local application server.

edx_exams/settings/devstack.py

@@ -53,6 +53,8 @@
 
 LMS_ROOT_URL = 'http://edx.devstack.lms:18000'
 
+# EVENT BUS
+
 EVENT_BUS_PRODUCER = 'edx_event_bus_kafka.create_producer'
 EVENT_BUS_CONSUMER = 'edx_event_bus_kafka.KafkaEventConsumer'
 EVENT_BUS_KAFKA_SCHEMA_REGISTRY_URL = 'http://edx.devstack.schema-registry:8081'

edx_exams/settings/local.py

@@ -135,11 +135,19 @@
 if os.path.isfile(join(dirname(abspath(__file__)), 'private.py')):
     from .private import *  # pylint: disable=import-error
 
+# EVENT BUS
+# Below are Django settings related to setting up the Open edX event bus.
+# Because the event bus requires a Docker based networking layer, as included in devstack, the event bus does not work
+# outside of a Docker container. Therefore, the settings related to networking are set to None, because this file is
+# used for the local application server. However, because these local Django settings are also used by Tutor, we include
+# sensible values for non-network related settings. Tutor users can override these settings when setting up the event
+# bus, including the network-related settings.
+
 EVENT_BUS_PRODUCER = 'edx_event_bus_kafka.create_producer'
 EVENT_BUS_CONSUMER = 'edx_event_bus_kafka.KafkaEventConsumer'
-EVENT_BUS_KAFKA_SCHEMA_REGISTRY_URL = 'http://edx.devstack.schema-registry:8081'
-EVENT_BUS_KAFKA_BOOTSTRAP_SERVERS = 'edx.devstack.kafka:29092'
 EVENT_BUS_TOPIC_PREFIX = 'dev'
+EVENT_BUS_KAFKA_SCHEMA_REGISTRY_URL = None
+EVENT_BUS_KAFKA_BOOTSTRAP_SERVERS = None
 
 # The EVENT_BUS_PRODUCER_CONFIG Django setting introduced in openedx-events 8.6.0 does not work properly.
 # In order to unblock development, EVENT_BUS_PRODUCER_CONFIG should be set to the empty object. Signal handlers