Simplify integrations cache on startupprobe (#3274)

Revert logic to detect integrations server on startupprobe and simplify
logic (and rework failing test having issues with urlpatterns cache and
reset), since cache is the same for engine and integrations, and it is
populated once.

engine/engine/tests/test_views.py

@@ -1,36 +1,12 @@
-import sys
-from importlib import import_module, reload
 from unittest.mock import patch
 
 import pytest
-from django.conf import settings
-from django.urls import clear_url_caches
 from rest_framework import status
 from rest_framework.test import APIClient
 
 
-def reload_urlconf():
-    clear_url_caches()
-    if settings.ROOT_URLCONF in sys.modules:
-        reload(sys.modules[settings.ROOT_URLCONF])
-    return import_module(settings.ROOT_URLCONF)
-
-
-@pytest.mark.skip(reason="TODO: This test is currently failing in oncall-private, skipping to unblock release")
-@pytest.mark.parametrize(
-    "detached_integrations,urlconf,is_cache_updated",
-    [
-        (False, None, True),
-        (True, None, False),
-        (True, "engine.integrations_urls", True),
-    ],
-)
-def test_startupprobe_populates_integrations_cache(settings, detached_integrations, urlconf, is_cache_updated):
-    settings.DETACHED_INTEGRATIONS_SERVER = detached_integrations
-    if urlconf:
-        settings.ROOT_URLCONF = urlconf
-    reload_urlconf()
-
+@pytest.mark.urls("engine.integrations_urls")
+def test_detached_integrations_startupprobe_populates_integrations_cache():
     client = APIClient()
 
     with patch(
@@ -39,4 +15,16 @@ def test_startupprobe_populates_integrations_cache(settings, detached_integratio
         response = client.get("/startupprobe/")
 
     assert response.status_code == status.HTTP_200_OK
-    assert mock_update_cache.called == is_cache_updated
+    mock_update_cache.assert_called_once
+
+
+def test_startupprobe_populates_integrations_cache():
+    client = APIClient()
+
+    with patch(
+        "apps.integrations.mixins.AlertChannelDefiningMixin.update_alert_receive_channel_cache"
+    ) as mock_update_cache:
+        response = client.get("/startupprobe/")
+
+    assert response.status_code == status.HTTP_200_OK
+    mock_update_cache.assert_called_once

engine/engine/views.py

@@ -1,4 +1,3 @@
-from django import urls
 from django.conf import settings
 from django.core.cache import cache
 from django.http import HttpResponse, JsonResponse
@@ -44,13 +43,7 @@ class StartupProbeView(View):
     dangerously_bypass_middlewares = True
 
     def get(self, request):
-        # enable integrations cache if current engine instance is serving them
-        integrations_enabled = True
-        if settings.DETACHED_INTEGRATIONS_SERVER:
-            url_resolver = urls.get_resolver(urls.get_urlconf())
-            integrations_enabled = url_resolver.namespace_dict.get("integrations")
-
-        if integrations_enabled and cache.get(AlertChannelDefiningMixin.CACHE_KEY_DB_FALLBACK) is None:
+        if cache.get(AlertChannelDefiningMixin.CACHE_KEY_DB_FALLBACK) is None:
             AlertChannelDefiningMixin().update_alert_receive_channel_cache()
 
         cache.set("healthcheck", "healthcheck", 30)  # Checking cache connectivity