Simplifies cachalot_settings and forbids its modification.

CHANGELOG.rst

@@ -17,8 +17,7 @@ master
 - Adds 2 settings to customize how cache keys are generated
 - Adds a benchmark
 - Adds file-based cache support for Django 1.7
-- Fixes overridden settings not working when they are already defined in
-  Django settings
+- Simplifies cachalot_settings and forbids its modification
 
 
 0.8.1

benchmark.py

@@ -13,12 +13,11 @@ from django.conf import settings
 from django.contrib.auth.models import User, Group
 from django.core.cache import get_cache
 from django.db import connections, connection
-from django.test.utils import CaptureQueriesContext
+from django.test.utils import CaptureQueriesContext, override_settings
 import matplotlib.pyplot as plt
 import pandas as pd
 
 from cachalot.api import invalidate_all
-from cachalot.settings import cachalot_settings
 from cachalot.tests.models import Test
 
 
@@ -71,7 +70,7 @@ class Benchmark(object):
             query_str = 'list(%s)' % query_str
         self.query_function = eval('lambda using: ' + query_str)
 
-        with cachalot_settings(CACHALOT_ENABLED=False):
+        with override_settings(CACHALOT_ENABLED=False):
             self.bench_once(CONTEXTS[0], num_queries)
 
         self.bench_once(CONTEXTS[1], num_queries, invalidate_before=True)
@@ -97,7 +96,7 @@ class Benchmark(object):
             for cache_alias in settings.CACHES:
                 cache = get_cache(cache_alias)
                 self.cache_name = cache.__class__.__name__[:-5].lower()
-                with cachalot_settings(CACHALOT_CACHE=cache_alias):
+                with override_settings(CACHALOT_CACHE=cache_alias):
                     self.execute_benchmark()
 
         self.df = pd.DataFrame.from_records(self.data)

cachalot/settings.py

@@ -1,32 +1,6 @@
-from functools import wraps
 from django.conf import settings
 
 
-class SettingsOverrider(object):
-    def __init__(self, settings, overrides):
-        self.settings = settings
-        self.overrides = overrides
-        self.originals = [(k, getattr(settings, k)) for k in overrides]
-        self.overridden = set(overrides) - settings.overridden
-
-    def __enter__(self):
-        self.settings.overridden.update(self.overridden)
-        for k, v in self.overrides.items():
-            setattr(self.settings, k, v)
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        for k, v in self.originals:
-            setattr(self.settings, k, v)
-        self.settings.overridden.difference_update(self.overridden)
-
-    def __call__(self, func):
-        @wraps(func)
-        def inner(*args, **kwargs):
-            with self:
-                return func(*args, **kwargs)
-        return inner
-
-
 class Settings(object):
     CACHALOT_ENABLED = True
     CACHALOT_CACHE = 'default'
@@ -35,17 +9,16 @@ class Settings(object):
     CACHALOT_QUERY_KEYGEN = 'cachalot.utils.get_query_cache_key'
     CACHALOT_TABLE_KEYGEN = 'cachalot.utils.get_table_cache_key'
 
-    def __init__(self):
-        self.overridden = set()
-
     def __getattribute__(self, item):
-        overridden = super(Settings, self).__getattribute__('overridden')
-        if hasattr(settings, item) and item not in overridden:
+        if hasattr(settings, item):
             return getattr(settings, item)
         return super(Settings, self).__getattribute__(item)
 
-    def __call__(self, **kwargs):
-        return SettingsOverrider(self, kwargs)
+    def __setattr__(self, key, value):
+        raise AttributeError(
+            "Don't modify `cachalot_settings`, use "
+            "`django.test.utils.override_settings` or "
+            "`django.conf.settings` instead.")
 
 
 cachalot_settings = Settings()

cachalot/tests/settings.py

@@ -10,13 +10,13 @@ from django.conf import settings
 from django.core.cache import DEFAULT_CACHE_ALIAS
 from django.db import connection
 from django.test import TransactionTestCase
+from django.test.utils import override_settings
 
-from ..settings import cachalot_settings
 from .models import Test
 
 
 class SettingsTestCase(TransactionTestCase):
-    @cachalot_settings(CACHALOT_ENABLED=False)
+    @override_settings(CACHALOT_ENABLED=False)
     def test_decorator(self):
         with self.assertNumQueries(1):
             list(Test.objects.all())
@@ -36,13 +36,13 @@ class SettingsTestCase(TransactionTestCase):
                     list(Test.objects.all())
 
     def test_enabled(self):
-        with cachalot_settings(CACHALOT_ENABLED=True):
+        with self.settings(CACHALOT_ENABLED=True):
             with self.assertNumQueries(1):
                 list(Test.objects.all())
             with self.assertNumQueries(0):
                 list(Test.objects.all())
 
-        with cachalot_settings(CACHALOT_ENABLED=False):
+        with self.settings(CACHALOT_ENABLED=False):
             with self.assertNumQueries(1):
                 list(Test.objects.all())
             with self.assertNumQueries(1):
@@ -53,7 +53,7 @@ class SettingsTestCase(TransactionTestCase):
 
         is_sqlite = connection.vendor == 'sqlite'
 
-        with cachalot_settings(CACHALOT_ENABLED=False):
+        with self.settings(CACHALOT_ENABLED=False):
             with self.assertNumQueries(2 if is_sqlite else 1):
                 t = Test.objects.create(name='test')
         with self.assertNumQueries(1):
@@ -63,7 +63,7 @@ class SettingsTestCase(TransactionTestCase):
     @skipIf(len(settings.CACHES) == 1,
             'We can’t change the cache used since there’s only one configured')
     def test_cache(self):
-        with cachalot_settings(CACHALOT_CACHE=DEFAULT_CACHE_ALIAS):
+        with self.settings(CACHALOT_CACHE=DEFAULT_CACHE_ALIAS):
             with self.assertNumQueries(1):
                 list(Test.objects.all())
             with self.assertNumQueries(0):
@@ -72,7 +72,7 @@ class SettingsTestCase(TransactionTestCase):
         other_cache_alias = [alias for alias in settings.CACHES
                              if alias != DEFAULT_CACHE_ALIAS][0]
 
-        with cachalot_settings(CACHALOT_CACHE=other_cache_alias):
+        with self.settings(CACHALOT_CACHE=other_cache_alias):
             with self.assertNumQueries(1):
                 list(Test.objects.all())
             with self.assertNumQueries(0):
@@ -84,7 +84,7 @@ class SettingsTestCase(TransactionTestCase):
         with self.assertNumQueries(1):
             list(Test.objects.order_by('?'))
 
-        with cachalot_settings(CACHALOT_CACHE_RANDOM=True):
+        with self.settings(CACHALOT_CACHE_RANDOM=True):
             with self.assertNumQueries(1):
                 list(Test.objects.order_by('?'))
             with self.assertNumQueries(0):

docs/quickstart.rst

@@ -81,26 +81,21 @@ Settings
 Dynamic overriding
 ~~~~~~~~~~~~~~~~~~
 
-Obviously, you can set these settings in your Django settings.
-But you can also change them whenever you want!
-Simply use ``cachalot_settings`` as a context manager, a decorator,
-or simply by changing its attributes:
+Django-cachalot is built so that its settings can be dynamically changed.
+
+For example:
 
 .. code:: python
 
-    from cachalot.settings import cachalot_settings
+    from django.conf import settings
+    from django.test.utils import override_settings
 
-    with cachalot_settings(CACHALOT_ENABLED=False):
+    with override_settings(CACHALOT_ENABLED=False):
         # SQL queries are not cached in this block
 
-    @cachalot_settings(CACHALOT_CACHE='another_alias')
+    @override_settings(CACHALOT_CACHE='another_alias')
     def your_function():
         # What’s in this function uses another cache
 
     # Globally disables SQL caching until you set it back to True
-    cachalot_settings.CACHALOT_ENABLED = False
-
-In tests, you can use
-`Django’s testing tools <https://docs.djangoproject.com/en/1.7/topics/testing/tools/#overriding-settings>`_
-as well as ``cachalot_settings``.  The only difference is that you can’t use
-``cachalot_settings`` to decorate a class.
+    settings.CACHALOT_ENABLED = False