From e8cff823d376ec1ce163ccf4fbdc9b90a59644d9 Mon Sep 17 00:00:00 2001
From: Bertrand Bordage <bordage.bertrand@gmail.com>
Date: Sun, 5 Oct 2014 02:36:19 +0200
Subject: [PATCH] Adds a CACHALOT_ENABLED setting.

---
 README.rst               | 15 ++++++++-------
 cachalot/monkey_patch.py |  3 ++-
 cachalot/settings.py     |  1 +
 cachalot/tests.py        | 23 +++++++++++++++++++++++
 4 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/README.rst b/README.rst
index 67ebc46..3074fa4 100644
--- a/README.rst
+++ b/README.rst
@@ -41,12 +41,14 @@ Usage
 Settings
 ........
 
-================== ============= ==============================================
-Setting            Default value Description
-================== ============= ==============================================
-``CACHALOT_CACHE`` ``'default'`` Name of the cache from |CACHES|_ used by
-                                 django-cachalot
-================== ============= ==============================================
+==================== ============= ============================================
+Setting              Default value Description
+==================== ============= ============================================
+``CACHALOT_ENABLED`` ``True``      If set to ``False``, disables SQL caching
+                                   but keeps invalidating to avoid stale cache
+``CACHALOT_CACHE``   ``'default'`` Name of the cache from |CACHES|_ used by
+                                   django-cachalot
+==================== ============= ============================================
 
 .. |CACHES| replace:: ``CACHES``
 .. _CACHES: https://docs.djangoproject.com/en/1.7/ref/settings/#std:setting-CACHES
@@ -119,7 +121,6 @@ For version 1.0
 - Add memcached support
 - Handle multiple databases
 - Add invalidation on migrations in Django 1.7 (& South?)
-- Add a ``CACHALOT_ENABLED`` setting
 
 In a more distant future
 ........................
diff --git a/cachalot/monkey_patch.py b/cachalot/monkey_patch.py
index da8deaf..8e237f5 100644
--- a/cachalot/monkey_patch.py
+++ b/cachalot/monkey_patch.py
@@ -165,7 +165,8 @@ def get_cache():
 def _patch_orm_read():
     def patch_execute_sql(original):
         def inner(compiler, *args, **kwargs):
-            if isinstance(compiler, WRITE_COMPILERS):
+            if not cachalot_settings.CACHALOT_ENABLED \
+                    or isinstance(compiler, WRITE_COMPILERS):
                 return original(compiler, *args, **kwargs)
 
             query = compiler.query
diff --git a/cachalot/settings.py b/cachalot/settings.py
index 7079041..9c79eaf 100644
--- a/cachalot/settings.py
+++ b/cachalot/settings.py
@@ -2,6 +2,7 @@ from django.conf import settings
 
 
 class Settings(object):
+    CACHALOT_ENABLED = True
     CACHALOT_CACHE = 'default'
 
     def __getattribute__(self, item):
diff --git a/cachalot/tests.py b/cachalot/tests.py
index 4a4b7f5..574544f 100644
--- a/cachalot/tests.py
+++ b/cachalot/tests.py
@@ -1178,6 +1178,29 @@ class AtomicTestCase(TestCase):
 
 
 class SettingsTestCase(TestCase):
+    def test_enabled(self):
+        with self.settings(CACHALOT_ENABLED=True):
+            with self.assertNumQueries(1):
+                list(Test.objects.all())
+            with self.assertNumQueries(0):
+                list(Test.objects.all())
+
+        with self.settings(CACHALOT_ENABLED=False):
+            with self.assertNumQueries(1):
+                list(Test.objects.all())
+            with self.assertNumQueries(1):
+                list(Test.objects.all())
+
+        with self.assertNumQueries(0):
+            list(Test.objects.all())
+
+        with self.settings(CACHALOT_ENABLED=False):
+            with self.assertNumQueries(1):
+                t = Test.objects.create(name='test')
+        with self.assertNumQueries(1):
+            data = list(Test.objects.all())
+        self.assertListEqual(data, [t])
+
     @skipIf(len(settings.CACHES) == 1,
             'We can’t change the cache used since there’s only one configured')
     def test_cache(self):