Allow configuring a routing key prefix

greg/management/commands/notification_publisher.py

@@ -21,14 +21,23 @@ def get_notifications(limit):
 def generate_event_type(n: Notification) -> str:
     """
     Generate CloudEvent compliant type field.
-
-    This can be used as routing key as well so that a future change to amqp where
-    routing key is removed results in minor changes to the code.
     """
     object_type = camel_to_snake(n.object_type)
     return f"{object_type}.{n.operation}"
 
 
+def generate_routing_key(n: Notification) -> str:
+    """
+    Generate an AMQP routing key.
+
+    By default this equals the payload type field, but is prefixed with the
+    value in settings.NOTIFICATION_ROUTING_KEY_PREFIX
+    """
+    event_type = generate_event_type(n)
+    prefix = settings.NOTIFICATION_ROUTING_KEY_PREFIX
+    return f"{prefix}{event_type}"
+
+
 def create_cloud_event_payload(n: Notification) -> str:
     """
     Produce a notification payload from a Notification object that matches CloudEvents
@@ -66,9 +75,7 @@ def handle_one_notification(notification: Notification, pcm: PCM, exchange: str)
     and delete the Notification afterwards.
     """
     payload = create_cloud_event_payload(notification)
-    # Use event_type for routing_key so that a future switch to amqp 1.0 that does not
-    # have routing keys is easier
-    routing_key = generate_event_type(notification)
+    routing_key = generate_routing_key(notification)
 
     if pcm.publish(
         exchange,

greg/tests/management/test_notification_publisher.py

@@ -4,6 +4,7 @@ import pytest
 from greg.management.commands.notification_publisher import (
     handle_one_notification,
     create_cloud_event_payload,
+    generate_routing_key,
 )
 from greg.models import Notification
 
@@ -41,3 +42,10 @@ def test_create_cloud_event_payload(role_type_notification):
         "type": "role_type.update",
         "data": {"integer": 123, "string": "foo"},
     }
+
+
+@pytest.mark.django_db
+def test_generate_routing_key(role_type_notification, settings):
+    assert generate_routing_key(role_type_notification) == "role_type.update"
+    settings.NOTIFICATION_ROUTING_KEY_PREFIX = "foo."
+    assert generate_routing_key(role_type_notification) == "foo.role_type.update"

gregsite/settings/base.py

@@ -266,6 +266,9 @@ structlog.configure(
 )
 
 
+# By default, the routing key format is "object_type.operation"
+# Setting the prefix to "foo." will result in "foo.object_type.operation"
+NOTIFICATION_ROUTING_KEY_PREFIX = ""
 NOTIFICATION_PUBLISHER = {
     "mq": {
         "connection": {