[WIP] Create missing model (Switch/Flag/Sample) in get_from_db

waffle/models.py

@@ -56,6 +56,13 @@ def get_from_db(cls, name):
         objects = cls.objects
         if get_setting('READ_FROM_WRITE_DB'):
             objects = objects.using(router.db_for_write(cls))
+
+        if get_setting(cls.CREATE_MISSING_SETTING):
+            obj, _created = objects.get_or_create(
+                name=name, defaults=cls._defaults()
+            )
+            return obj
+
         return objects.get(name=name)
 
     @classmethod
@@ -197,12 +204,17 @@ class AbstractBaseFlag(BaseModel):
 
     SINGLE_CACHE_KEY = 'FLAG_CACHE_KEY'
     ALL_CACHE_KEY = 'ALL_FLAGS_CACHE_KEY'
+    CREATE_MISSING_SETTING = 'CREATE_MISSING_FLAGS'
 
     class Meta:
         abstract = True
         verbose_name = _('Flag')
         verbose_name_plural = _('Flags')
 
+    @classmethod
+    def _defaults(cls):
+        return {'everyone': get_setting('FLAG_DEFAULT')}
+
     def flush(self):
         cache = get_cache()
         keys = self.get_flush_keys()
@@ -247,16 +259,6 @@ def is_active(self, request):
             log_level = get_setting('LOG_MISSING_FLAGS')
             if log_level:
                 logger.log(log_level, 'Flag %s not found', self.name)
-            if get_setting('CREATE_MISSING_FLAGS'):
-                flag, _created = get_waffle_flag_model().objects.get_or_create(
-                    name=self.name,
-                    defaults={
-                        'everyone': get_setting('FLAG_DEFAULT')
-                    }
-                )
-                cache = get_cache()
-                cache.set(self._cache_key(self.name), flag)
-
             return get_setting('FLAG_DEFAULT')
 
         if get_setting('OVERRIDE'):
@@ -443,25 +445,21 @@ class Switch(BaseModel):
 
     SINGLE_CACHE_KEY = 'SWITCH_CACHE_KEY'
     ALL_CACHE_KEY = 'ALL_SWITCHES_CACHE_KEY'
+    CREATE_MISSING_SETTING = 'CREATE_MISSING_SWITCHES'
 
     class Meta:
         verbose_name = _('Switch')
         verbose_name_plural = _('Switches')
 
+    @classmethod
+    def _defaults(cls):
+        return {'active': get_setting('SWITCH_DEFAULT')}
+
     def is_active(self):
         if not self.pk:
             log_level = get_setting('LOG_MISSING_SWITCHES')
             if log_level:
                 logger.log(log_level, 'Switch %s not found', self.name)
-            if get_setting('CREATE_MISSING_SWITCHES'):
-                switch, _created = Switch.objects.get_or_create(
-                    name=self.name,
-                    defaults={
-                        'active': get_setting('SWITCH_DEFAULT')
-                    }
-                )
-                cache = get_cache()
-                cache.set(self._cache_key(self.name), switch)
 
             return get_setting('SWITCH_DEFAULT')
 
@@ -510,28 +508,22 @@ class Sample(BaseModel):
 
     SINGLE_CACHE_KEY = 'SAMPLE_CACHE_KEY'
     ALL_CACHE_KEY = 'ALL_SAMPLES_CACHE_KEY'
+    CREATE_MISSING_SETTING = 'CREATE_MISSING_SAMPLES'
 
     class Meta:
         verbose_name = _('Sample')
         verbose_name_plural = _('Samples')
 
+    @classmethod
+    def _defaults(cls):
+        default_percent = 100 if get_setting('SAMPLE_DEFAULT') else 0
+        return {'percent': default_percent}
+
     def is_active(self):
         if not self.pk:
             log_level = get_setting('LOG_MISSING_SAMPLES')
             if log_level:
                 logger.log(log_level, 'Sample %s not found', self.name)
-            if get_setting('CREATE_MISSING_SAMPLES'):
-
-                default_percent = 100 if get_setting('SAMPLE_DEFAULT') else 0
-
-                sample, _created = Sample.objects.get_or_create(
-                    name=self.name,
-                    defaults={
-                        'percent': default_percent
-                    }
-                )
-                cache = get_cache()
-                cache.set(self._cache_key(self.name), sample)
 
             return get_setting('SAMPLE_DEFAULT')
         return Decimal(str(random.uniform(0, 100))) <= self.percent

waffle/tests/test_waffle.py

@@ -441,6 +441,16 @@ def test_flag_created_dynamically_default_false(self):
     def test_flag_created_dynamically_default_true(self):
         self.assert_flag_dynamically_created_with_value(True)
 
+    @override_settings(WAFFLE_CREATE_MISSING_FLAGS=True)
+    @override_settings(WAFFLE_FLAG_DEFAULT=True)
+    def test_flag_created_dynamically_upon_retrieval(self):
+        FLAG_NAME = 'myflag'
+        flag_model = waffle.get_waffle_flag_model()
+        flag = flag_model.get(FLAG_NAME)
+
+        assert flag.is_active(get())
+        assert flag_model.objects.filter(name=FLAG_NAME).exists()
+
     @mock.patch('waffle.models.logger')
     def test_no_logging_missing_flag_by_default(self, mock_logger):
         request = get()