singleton warning: method_is_called_from

Author: kp-cat

configcatclient/configcatclient.py

@@ -14,46 +14,13 @@
 import hashlib
 from collections import namedtuple
 import copy
-import inspect
+from .utils import method_is_called_from
 
 log = logging.getLogger(sys.modules[__name__].__name__)
 
 KeyValue = namedtuple('KeyValue', 'key value')
 
 
-def get_class_from_stack_frame(frame):
-    args, _, _, value_dict = inspect.getargvalues(frame)
-    # we check the first parameter for the frame function is
-    # named 'self' or 'cls'
-    if len(args):
-        if args[0] == 'self':
-            # in that case, 'self' will be referenced in value_dict
-            instance = value_dict.get(args[0], None)
-            if instance:
-                # return its class
-                return getattr(instance, '__class__', None)
-        if args[0] == 'cls':
-            # return the class
-            return value_dict.get(args[0], None)
-
-    # return None otherwise
-    return None
-
-
-def guard_call(allowed_classes, level=1):
-    """
-    Checks if the current method is being called from a method of certain classes.
-    """
-    stack_info = inspect.stack()[level + 1]
-    frame = stack_info[0]
-    calling_class = get_class_from_stack_frame(frame)
-    if calling_class:
-        for klass in allowed_classes:
-            if issubclass(calling_class, klass):
-                return True
-    return False
-
-
 class ConfigCatClient(object):
     _instances = {}
 
@@ -85,7 +52,7 @@ def __init__(self,
                  sdk_key,
                  options=ConfigCatOptions()):
 
-        if not guard_call([ConfigCatClient]):
+        if not method_is_called_from(ConfigCatClient.get):
             log.warning('ConfigCatClient.__init__() is deprecated. '
                         'Create the ConfigCat Client as a Singleton object with `ConfigCatClient.get()` instead')
 

configcatclient/utils.py

@@ -0,0 +1,51 @@
+import sys
+import inspect
+from qualname import qualname
+
+
+def get_class_from_method(method):
+    method_class = sys.modules.get(method.__module__)
+    if method_class is None:
+        return None
+    for name in qualname(method).split('.')[:-1]:
+        method_class = getattr(method_class, name)
+    if not inspect.isclass(method_class):
+        return None
+    return method_class
+
+
+def get_class_from_stack_frame(frame):
+    args, _, _, value_dict = inspect.getargvalues(frame)
+    # we check the first parameter for the frame function is
+    # named 'self' or 'cls'
+    if len(args):
+        if args[0] == 'self':
+            # in that case, 'self' will be referenced in value_dict
+            instance = value_dict.get(args[0], None)
+            if instance:
+                # return its class
+                return getattr(instance, '__class__', None)
+        if args[0] == 'cls':
+            # return the class
+            return value_dict.get(args[0], None)
+
+    # return None otherwise
+    return None
+
+
+def method_is_called_from(method, level=1):
+    """
+    Checks if the current method is being called from a certain method.
+    """
+    stack_info = inspect.stack()[level + 1]
+    frame = stack_info[0]
+    calling_method_name = frame.f_code.co_name
+    expected_method_name = method.__name__
+    if calling_method_name != expected_method_name:
+        return False
+
+    calling_class = get_class_from_stack_frame(frame)
+    expected_class = get_class_from_method(method)
+    if calling_class == expected_class:
+        return True
+    return False

configcatclienttests/test_configcatclient.py

@@ -28,7 +28,7 @@ def test_ensure_singleton_per_sdk_key(self):
 
     def test_without_sdk_key(self):
         try:
-            ConfigCatClient.get(None)
+            ConfigCatClient(None)
             self.fail('Expected ConfigCatClientException')
         except ConfigCatClientException:
             pass

configcatclienttests/test_utils.py

@@ -0,0 +1,51 @@
+import logging
+import unittest
+
+from configcatclient.utils import method_is_called_from
+
+logging.basicConfig(level=logging.INFO)
+
+
+def no_operation():
+    pass
+
+
+def test_method_is_called_from():
+    pass
+
+
+class OtherClass(object):
+    def no_operation(self):
+        pass
+
+    def test_method_is_called_from(self):
+        pass
+
+
+class UtilsTests(unittest.TestCase):
+    def no_operation(self):
+        pass
+
+    def test_method_is_called_from(self):
+        class TestClass(object):
+            @classmethod
+            def class_method(cls, method):
+                return method_is_called_from(method)
+
+            def object_method(self, method):
+                return method_is_called_from(method)
+
+        self.assertTrue(TestClass.class_method(UtilsTests.test_method_is_called_from))
+        self.assertTrue(TestClass().object_method(UtilsTests.test_method_is_called_from))
+
+        self.assertFalse(TestClass.class_method(UtilsTests.no_operation))
+        self.assertFalse(TestClass().object_method(UtilsTests.no_operation))
+
+        self.assertFalse(TestClass.class_method(no_operation))
+        self.assertFalse(TestClass().object_method(test_method_is_called_from))
+        self.assertFalse(TestClass.class_method(OtherClass.no_operation))
+        self.assertFalse(TestClass().object_method(OtherClass.test_method_is_called_from))
+
+
+if __name__ == '__main__':
+    unittest.main()

requirements.txt

@@ -1,3 +1,4 @@
 requests>=2.17.3
 semver>=2.8.1
-enum-compat>=0.0.3
+enum-compat>=0.0.3
+qualname>=0.1.0