117 django middleware only applies to default database connections ignoring other databases (#127)

Add support for multiple connection in django sqlcommenter

We used the `connections` middleware instead of `connections` to support multiple databases instead of only the default database.

TESTED=unittests

Author: Thiyagu55

python/sqlcommenter-python/google/cloud/sqlcommenter/django/middleware.py

@@ -15,9 +15,11 @@
 # limitations under the License.
 
 import logging
+from contextlib import ExitStack
 
 import django
-from django.db import connection
+from django.db import connections
+
 from django.db.backends.utils import CursorDebugWrapper
 from google.cloud.sqlcommenter import add_sql_comment
 from google.cloud.sqlcommenter.opencensus import get_opencensus_values
@@ -36,7 +38,9 @@ def __init__(self, get_response):
         self.get_response = get_response
 
     def __call__(self, request):
-        with connection.execute_wrapper(QueryWrapper(request)):
+        with ExitStack() as stack:
+            for db_alias in connections:
+                stack.enter_context(connections[db_alias].execute_wrapper(QueryWrapper(request)))
             return self.get_response(request)
 
 
@@ -88,7 +92,7 @@ def __call__(self, execute, sql, params, many, context):
         #  * https://github.com/basecamp/marginalia/pull/80
 
         # Add the query to the query log if debugging.
-        if context['cursor'].__class__ is CursorDebugWrapper:
+        if isinstance(context['cursor'], CursorDebugWrapper):
             context['connection'].queries_log.append(sql)
 
         return execute(sql, params, many, context)

python/sqlcommenter-python/tests/django/settings.py

@@ -18,6 +18,10 @@
     'default': {
         'ENGINE': 'django.db.backends.sqlite3',
     },
+
+    'other': {
+        'ENGINE': 'django.db.backends.sqlite3',
+    },
 }
 
 INSTALLED_APPS = ['tests.django']

python/sqlcommenter-python/tests/django/tests.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 import django
-from django.db import connection
+from django.db import connection, connections
 from django.http import HttpRequest
 from django.test import TestCase, override_settings, modify_settings
 from django.urls import resolve, reverse
@@ -41,7 +41,7 @@ def __call__(self, request):
 # Query log only active if DEBUG=True.
 @override_settings(DEBUG=True)
 class Tests(TestCase):
-
+    databases = '__all__'
     @staticmethod
     def get_request(path):
         request = HttpRequest()
@@ -55,6 +55,13 @@ def get_query(self, path='/'):
         self.assertEqual(len(connection.queries), 2)
         return connection.queries[0]
 
+    def get_query_other_db(self, path='/', connection_name='default'):
+        SqlCommenter(views.home_other_db)(self.get_request(path))
+        # Query with comment added by QueryWrapper and unaltered query added
+        # by Django's CursorDebugWrapper.
+        self.assertEqual(len(connections[connection_name].queries), 2)
+        return connections[connection_name].queries[0]
+
     def assertRoute(self, route, query):
         # route available in Django 2.2 and later.
         if django.VERSION < (2, 2):
@@ -69,6 +76,13 @@ def test_basic(self):
         self.assertIn("framework='django%%3A" + django.get_version(), query)
         self.assertRoute('', query)
 
+    def test_basic_multiple_db_support(self):
+        query = self.get_query_other_db(path='/other/', connection_name='other')
+        self.assertIn("/*controller='some-other-db-path'", query)
+        # Expecting url_quoted("framework='django:'")
+        self.assertIn("framework='django%%3A" + django.get_version(), query)
+        self.assertRoute('other/', query)
+
     def test_basic_disabled(self):
         with self.settings(
                 SQLCOMMENTER_WITH_CONTROLLER=False, SQLCOMMENTER_WITH_ROUTE=False,

python/sqlcommenter-python/tests/django/urls.py

@@ -21,5 +21,6 @@
 urlpatterns = [
     path('', views.home, name='home'),
     path('path/', views.home, name='some-path'),
+    path('other/', views.home_other_db, name='some-other-db-path'),
     path('app-urls/', include('tests.django.app_urls')),
 ]

python/sqlcommenter-python/tests/django/views.py

@@ -20,5 +20,10 @@
 
 
 def home(request):
-    list(Author.objects.all())
+    list(Author.objects.all().using('default'))
+    return HttpResponse()
+
+
+def home_other_db(request):
+    list(Author.objects.all().using('other'))
     return HttpResponse()