Add get feature flag method (#67)

* get feature flag method

* remove groups param from method

* use personal api key

* add groups

* add capture

* black reformat

* black?

* Update posthog/client.py

Co-authored-by: Neil Kakkar <[email protected]>

* add to init

* formatting

Co-authored-by: Neil Kakkar <[email protected]>

Author: liyiy

posthog/__init__.py

@@ -254,6 +254,20 @@ def feature_enabled(
     return _proxy("feature_enabled", key=key, distinct_id=distinct_id, default=default, groups=groups)
 
 
+def get_feature_flag(key, distinct_id, groups):
+    """
+    Get feature flag variant for users. Used with experiments.
+    Example:
+    ```python
+    if posthog.get_feature_flag('beta-feature', 'distinct_id') == 'test-variant':
+        # do test variant code
+    if posthog.get_feature_flag('beta-feature', 'distinct_id') == 'control':
+        # do control code
+    ```
+    """
+    return _proxy("get_feature_flag", key=key, distinct_id=distinct_id, groups=groups)
+
+
 def page(*args, **kwargs):
     """Send a page call."""
     _proxy("page", *args, **kwargs)

posthog/client.py

@@ -412,10 +412,21 @@ def feature_enabled(self, key, distinct_id, default=False, *, groups={}):
                 self.log.exception(f"[FEATURE FLAGS] Unable to get feature variants: {e}")
                 response = default
             else:
-                response = feature_flags.get(key, default)
+                response = True if feature_flags.get(key) else default
         self.capture(distinct_id, "$feature_flag_called", {"$feature_flag": key, "$feature_flag_response": response})
         return response
 
+    def get_feature_flag(self, key, distinct_id, groups={}):
+        require("key", key, string_types)
+        require("distinct_id", distinct_id, ID_TYPES)
+        require("groups", groups, dict)
+
+        variants = self.get_feature_variants(distinct_id, groups=groups)
+        self.capture(
+            distinct_id, "$feature_flag_called", {"$feature_flag": key, "$feature_flag_response": variants.get(key)}
+        )
+        return variants.get(key)
+
 
 # This function takes a distinct_id and a feature flag key and returns a float between 0 and 1.
 # Given the same distinct_id and key, it'll always return the same float. These floats are

posthog/test/test_client.py

@@ -524,7 +524,7 @@ def test_feature_enabled_request_multi_variate(self, patch_decide):
         client.feature_flags = [
             {"id": 1, "name": "Beta Feature", "key": "beta-feature", "is_simple_flag": False, "rollout_percentage": 100}
         ]
-        self.assertEqual(client.feature_enabled("beta-feature", "distinct_id"), "variant-1")
+        self.assertTrue(client.feature_enabled("beta-feature", "distinct_id"))
 
     @mock.patch("posthog.client.get")
     def test_feature_enabled_simple_without_rollout_percentage(self, patch_get):
@@ -536,10 +536,19 @@ def test_feature_enabled_simple_without_rollout_percentage(self, patch_get):
     def test_feature_enabled_simple_with_none_rollout_percentage(self, patch_get):
         client = Client(TEST_API_KEY)
         client.feature_flags = [
-            {"id": 1, "name": "Beta Feature", "key": "beta-feature", "is_simple_flag": True, "rollout_percantage": None}
+            {"id": 1, "name": "Beta Feature", "key": "beta-feature", "is_simple_flag": True, "rollout_percentage": None}
         ]
         self.assertTrue(client.feature_enabled("beta-feature", "distinct_id"))
 
+    @mock.patch("posthog.client.decide")
+    def test_get_feature_flag(self, patch_decide):
+        patch_decide.return_value = {"featureFlags": {"beta-feature": "variant-1"}}
+        client = Client(TEST_API_KEY, personal_api_key="test")
+        client.feature_flags = [
+            {"id": 1, "name": "Beta Feature", "key": "beta-feature", "is_simple_flag": False, "rollout_percentage": 100}
+        ]
+        self.assertEqual(client.get_feature_flag("beta-feature", "distinct_id"), "variant-1")
+
     @mock.patch("posthog.client.Poller")
     @mock.patch("posthog.client.decide")
     def test_feature_enabled_doesnt_exist(self, patch_decide, patch_poll):