2-level memoize

* Allows for invalidating an entire function from the memoizer

awx/conf/license.py

@@ -2,7 +2,6 @@
 # All Rights Reserved.
 
 # Django
-from django.core.cache import cache
 from django.core.signals import setting_changed
 from django.dispatch import receiver
 from django.utils.translation import ugettext_lazy as _
@@ -12,7 +11,7 @@ from rest_framework.exceptions import APIException
 
 # Tower
 from awx.main.utils.common import get_licenser
-from awx.main.utils import memoize
+from awx.main.utils import memoize, memoize_delete
 
 __all__ = ['LicenseForbids', 'get_license', 'get_licensed_features',
            'feature_enabled', 'feature_exists']
@@ -23,7 +22,6 @@ class LicenseForbids(APIException):
     default_detail = _('Your Tower license does not allow that.')
 
 
-@memoize(cache_key='_validated_license_data')
 def _get_validated_license_data():
     return get_licenser().validate()
 
@@ -32,7 +30,7 @@ def _get_validated_license_data():
 def _on_setting_changed(sender, **kwargs):
     # Clear cached result above when license changes.
     if kwargs.get('setting', None) == 'LICENSE':
-        cache.delete('_validated_license_data')
+        memoize_delete('feature_enabled')
 
 
 def get_license(show_key=False):
@@ -52,6 +50,7 @@ def get_licensed_features():
     return features
 
 
+@memoize(track_function=True)
 def feature_enabled(name):
     """Return True if the requested feature is enabled, False otherwise."""
     validated_license_data = _get_validated_license_data()

awx/main/tests/unit/utils/test_common.py

@@ -6,6 +6,8 @@ import os
 import pytest
 from uuid import uuid4
 
+from django.core.cache import cache
+
 from awx.main.utils import common
 
 from awx.main.models import (
@@ -18,6 +20,14 @@ from awx.main.models import (
 )
 
 
+@pytest.fixture(autouse=True)
+def clear_cache():
+    '''
+    Clear cache (local memory) for each test to prevent using cached settings.
+    '''
+    cache.clear()
+
+
 @pytest.mark.parametrize('input_, output', [
     ({"foo": "bar"}, {"foo": "bar"}),
     ('{"foo": "bar"}', {"foo": "bar"}),
@@ -49,3 +59,59 @@ def test_set_environ():
 ])
 def test_get_type_for_model(model, name):
     assert common.get_type_for_model(model) == name
+
+
+@pytest.fixture
+def memoized_function(mocker):
+    @common.memoize(track_function=True)
+    def myfunction(key, value):
+        if key not in myfunction.calls:
+            myfunction.calls[key] = 0
+
+        myfunction.calls[key] += 1
+
+        if myfunction.calls[key] == 1:
+            return value
+        else:
+            return '%s called %s times' % (value, myfunction.calls[key])
+    myfunction.calls = dict()
+    return myfunction
+
+
+def test_memoize_track_function(memoized_function):
+    assert memoized_function('scott', 'scotterson') == 'scotterson'
+    assert cache.get('myfunction') == {u'scott-scotterson': 'scotterson'}
+    assert memoized_function('scott', 'scotterson') == 'scotterson'
+
+    assert memoized_function.calls['scott'] == 1
+
+    assert memoized_function('john', 'smith') == 'smith'
+    assert cache.get('myfunction') == {u'scott-scotterson': 'scotterson', u'john-smith': 'smith'}
+    assert memoized_function('john', 'smith') == 'smith'
+    
+    assert memoized_function.calls['john'] == 1
+
+
+def test_memoize_delete(memoized_function):
+    assert memoized_function('john', 'smith') == 'smith'
+    assert memoized_function('john', 'smith') == 'smith'
+    assert memoized_function.calls['john'] == 1
+    
+    assert cache.get('myfunction') == {u'john-smith': 'smith'}
+
+    common.memoize_delete('myfunction')
+
+    assert cache.get('myfunction') is None
+
+    assert memoized_function('john', 'smith') == 'smith called 2 times'
+    assert memoized_function.calls['john'] == 2
+
+
+def test_memoize_parameter_error():
+    @common.memoize(cache_key='foo', track_function=True)
+    def fn():
+        return
+
+    with pytest.raises(common.IllegalArgumentError):
+        fn()
+

awx/main/utils/common.py

@@ -34,7 +34,7 @@ from django.apps import apps
 
 logger = logging.getLogger('awx.main.utils')
 
-__all__ = ['get_object_or_400', 'get_object_or_403', 'camelcase_to_underscore', 'memoize',
+__all__ = ['get_object_or_400', 'get_object_or_403', 'camelcase_to_underscore', 'memoize', 'memoize_delete',
            'get_ansible_version', 'get_ssh_version', 'get_licenser', 'get_awx_version', 'update_scm_url',
            'get_type_for_model', 'get_model_for_type', 'copy_model_by_class',
            'copy_m2m_relationships' ,'cache_list_capabilities', 'to_python_boolean',
@@ -44,7 +44,7 @@ __all__ = ['get_object_or_400', 'get_object_or_403', 'camelcase_to_underscore',
            'callback_filter_out_ansible_extra_vars', 'get_search_fields', 'get_system_task_capacity',
            'wrap_args_with_proot', 'build_proot_temp_dir', 'check_proot_installed', 'model_to_dict',
            'model_instance_diff', 'timestamp_apiformat', 'parse_yaml_or_json', 'RequireDebugTrueOrTest',
-           'has_model_field_prefetched', 'set_environ']
+           'has_model_field_prefetched', 'set_environ', 'IllegalArgumentError',]
 
 
 def get_object_or_400(klass, *args, **kwargs):
@@ -107,22 +107,48 @@ class RequireDebugTrueOrTest(logging.Filter):
         return settings.DEBUG or 'test' in sys.argv
 
 
-def memoize(ttl=60, cache_key=None):
+class IllegalArgumentError(ValueError):
+    pass
+
+
+def memoize(ttl=60, cache_key=None, track_function=False):
     '''
     Decorator to wrap a function and cache its result.
     '''
     from django.core.cache import cache
 
+
     def _memoizer(f, *args, **kwargs):
-        key = cache_key or slugify('%s %r %r' % (f.__name__, args, kwargs))
-        value = cache.get(key)
-        if value is None:
-            value = f(*args, **kwargs)
-            cache.set(key, value, ttl)
+        if cache_key and track_function:
+            raise IllegalArgumentError("Can not specify cache_key when track_function is True")
+
+        if track_function:
+            cache_dict_key = slugify('%r %r' % (args, kwargs))
+            key = slugify("%s" % f.__name__)
+            cache_dict = cache.get(key) or dict()
+            if cache_dict_key not in cache_dict:
+                value = f(*args, **kwargs)
+                cache_dict[cache_dict_key] = value
+                cache.set(key, cache_dict, ttl)
+            else:
+                value = cache_dict[cache_dict_key]
+        else:
+            key = cache_key or slugify('%s %r %r' % (f.__name__, args, kwargs))
+            value = cache.get(key)
+            if value is None:
+                value = f(*args, **kwargs)
+                cache.set(key, value, ttl)
+
         return value
     return decorator(_memoizer)
 
 
+def memoize_delete(function_name):
+    from django.core.cache import cache
+
+    return cache.delete(function_name)
+
+
 @memoize()
 def get_ansible_version():
     '''