Add check to service_health for Enketo Redis main

kobo/apps/__init__.py

@@ -1,7 +1,6 @@
 # coding: utf-8
 from django.apps import AppConfig
-from django.conf import settings
-from django.core.checks import register, Tags, Error
+from django.core.checks import register, Tags
 
 from kpi.utils.two_database_configuration_checker import \
     TwoDatabaseConfigurationChecker
@@ -19,27 +18,3 @@ def ready(self, *args, **kwargs):
 
 
 register(TwoDatabaseConfigurationChecker().as_check(), Tags.database)
-
-
-@register()
-def check_enketo_redis_main_url(app_configs, **kwargs):
-    """
-    `ENKETO_REDIS_MAIN_URL` is required to make the app run properly.
-    """
-    errors = []
-
-    if not settings.CACHES.get('enketo_redis_main'):
-        # We need to set `BACKEND` property. Otherwise, this error is shadowed
-        # by DRF system checks.
-        settings.CACHES['enketo_redis_main']['BACKEND'] = (
-            'django.core.cache.backends.dummy.DummyCache'
-        )
-        errors.append(
-            Error(
-                f'Please set environment variable `ENKETO_REDIS_MAIN_URL`',
-                hint='Enketo Express Redis main URL is missing.',
-                obj=settings,
-                id='kpi.enketo_redis_main.E001',
-            )
-        )
-    return errors

kobo/apps/service_health/views.py

@@ -4,7 +4,7 @@
 
 import requests
 from django.conf import settings
-from django.core.cache import cache
+from django.core.cache import cache, caches
 from django.http import HttpResponse
 
 from kobo.celery import celery_app
@@ -75,6 +75,7 @@ def service_health(request):
         'Enketo': lambda: requests.get(
             settings.ENKETO_INTERNAL_URL, timeout=10
         ).raise_for_status(),
+        'Enketo Redis (main)': lambda: caches['enketo_redis_main'].set('a', True, 1),
     }
 
     check_results = []

kobo/settings/base.py

@@ -1301,8 +1301,10 @@ def dj_stripe_request_callback_method():
 
 CACHES = {
     # Set CACHE_URL to override
-    'default': env.cache(default='redis://redis_cache:6380/3'),
-    'enketo_redis_main': env.cache(var='ENKETO_REDIS_MAIN_URL', default=None)
+    'default': env.cache_url(default='redis://redis_cache:6380/3'),
+    'enketo_redis_main': env.cache_url(
+        'ENKETO_REDIS_MAIN_URL', default='redis://change-me.invalid/0'
+    ),
 }
 
 # How long to retain cached responses for kpi endpoints