Merge pull request #5048 from kobotoolbox/TASK-931-minimal-healthcheck-middleware

[Task 931] Minimal health-check middleware

Author: bufke

hub/middleware.py

@@ -4,7 +4,6 @@
 
 
 class LocaleMiddleware(DjangoLocaleMiddleware):
-
     def process_response(self, request, response):
         response = super().process_response(request, response)
         try:

kobo/apps/openrosa/apps/main/service_health.py

@@ -47,6 +47,3 @@ def service_health(request):
     return HttpResponse(
         output, status=(500 if any_failure else 200), content_type='text/plain'
     )
-
-def service_health_minimal(request):
-    return HttpResponse('ok', content_type='text/plain')

kobo/apps/openrosa/apps/main/tests/test_service_health_minimal.py

@@ -1,7 +1,7 @@
 # coding: utf-8
 from django.conf import settings
 
-from django.urls import include, re_path, path
+from django.urls import include, re_path
 from django.views.generic import RedirectView
 from django.views.i18n import JavaScriptCatalog
 
@@ -10,10 +10,7 @@
 from kobo.apps.openrosa.apps.api.urls import XFormListApi
 from kobo.apps.openrosa.apps.api.urls import XFormSubmissionApi
 from kobo.apps.openrosa.apps.api.urls import router, router_with_patch_list
-from kobo.apps.openrosa.apps.main.service_health import (
-    service_health,
-    service_health_minimal,
-)
+from kobo.apps.openrosa.apps.main.service_health import service_health
 
 # exporting stuff
 from kobo.apps.openrosa.apps.viewer.views import (
@@ -38,11 +35,6 @@
     re_path('^api/v1/', include(router.urls)),
     re_path('^api/v1/', include(router_with_patch_list.urls)),
     re_path(r'^legacy/service_health/$', service_health, name='legacy-service-health'),
-    path(
-        'legacy/service_health/minimal/',
-        service_health_minimal,
-        name='legacy-service-health-minimal',
-    ),
 
     # main website views
     re_path(

kobo/apps/openrosa/apps/main/urls.py

@@ -0,0 +1,17 @@
+from django.http import HttpResponse
+
+
+class HealthCheckMiddleware:
+    """
+    Provides healthcheck URL that skips other middleware.
+    Add this before SecurityMiddleware.
+    https://stackoverflow.com/a/64623669
+    """
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        if request.path == '/service_health/minimal/':
+            return HttpResponse('ok', content_type='text/plain')
+        return self.get_response(request)

kobo/apps/service_health/middleware.py

@@ -1,14 +1,14 @@
-from django.test import TestCase
-from django.urls import reverse
+from django.test import TestCase, override_settings
 
 
 class ServiceHealthMinimalTestCase(TestCase):
-    url = reverse('service-health-minimal')
+    url = '/service_health/minimal/'  # Path checked in middleware, can't use reverse
 
+    @override_settings(ALLOWED_HOSTS=['nope'])
     def test_service_health_minimal(self):
         """
         Test for endpoint which makes no connections to databases or other external
-        services and is helpful for HTTP health checks.
+        services, ignores ALLOWED_HOSTS, and is helpful for HTTP health checks.
         """
         with self.assertNumQueries(0):
             res = self.client.get(self.url)

kobo/apps/service_health/test_service_health_minimal.py

@@ -1,12 +1,7 @@
 from django.urls import path
 
-from .views import service_health, service_health_minimal
+from .views import service_health
 
 urlpatterns = [
     path('service_health/', service_health, name='service-health'),
-    path(
-        'service_health/minimal/',
-        service_health_minimal,
-        name='service-health-minimal',
-    ),
 ]

kobo/apps/service_health/urls.py

@@ -113,7 +113,3 @@ def service_health(request):
     return HttpResponse(
         output, status=(500 if any_failure else 200), content_type='text/plain'
     )
-
-
-def service_health_minimal(request):
-    return HttpResponse('ok', content_type='text/plain')

kobo/apps/service_health/views.py

@@ -147,6 +147,7 @@
 )
 
 MIDDLEWARE = [
+    'kobo.apps.service_health.middleware.HealthCheckMiddleware',
     'kobo.apps.openrosa.koboform.redirect_middleware.ConditionalRedirects',
     'kobo.apps.openrosa.apps.main.middleware.RevisionMiddleware',
     'django_dont_vary_on.middleware.RemoveUnneededVaryHeadersMiddleware',