feat: implement api-level hooks

Signed-off-by: Federico Bond <[email protected]>

Author: federicobond

open_feature/hooks/__init__.py

@@ -0,0 +1,21 @@
+import typing
+
+from open_feature.hooks.hook import Hook
+
+
+_hooks: typing.List[Hook] = []
+
+
+def add_api_hooks(hooks: typing.List[Hook]):
+    global _hooks
+    _hooks = _hooks + hooks
+
+
+def clear_api_hooks():
+    global _hooks
+    _hooks = []
+
+
+def api_hooks() -> typing.List[Hook]:
+    global _hooks
+    return _hooks

open_feature/open_feature_client.py

@@ -13,6 +13,7 @@
 from open_feature.flag_evaluation.flag_type import FlagType
 from open_feature.flag_evaluation.reason import Reason
 from open_feature.flag_evaluation.resolution_details import FlagResolutionDetails
+from open_feature.hooks import api_hooks
 from open_feature.hooks.hook import Hook
 from open_feature.hooks.hook_context import HookContext
 from open_feature.hooks.hook_support import (
@@ -248,13 +249,14 @@ def evaluate_flag_details(
             client_metadata=None,
             provider_metadata=None,
         )
-        # Todo add api level hooks
-        # https://github.com/open-feature/spec/blob/main/specification/sections/04-hooks.md#requirement-442
         # Hooks need to be handled in different orders at different stages
         # in the flag evaluation
         # before: API, Client, Invocation, Provider
         merged_hooks = (
-            self.hooks + evaluation_hooks + self.provider.get_provider_hooks()
+            api_hooks()
+            + self.hooks
+            + evaluation_hooks
+            + self.provider.get_provider_hooks()
         )
         # after, error, finally: Provider, Invocation, Client, API
         reversed_merged_hooks = merged_hooks[:]

tests/hooks/test_init.py

@@ -0,0 +1,18 @@
+from unittest.mock import MagicMock
+
+from open_feature.hooks.hook import Hook
+from open_feature.hooks import add_api_hooks, clear_api_hooks, api_hooks
+
+
+def test_should_add_hooks_to_api_hooks():
+    # Given
+    hook_1 = MagicMock(spec=Hook)
+    hook_2 = MagicMock(spec=Hook)
+    clear_api_hooks()
+
+    # When
+    add_api_hooks([hook_1])
+    add_api_hooks([hook_2])
+
+    # Then
+    assert api_hooks() == [hook_1, hook_2]

tests/test_open_feature_client.py

@@ -5,6 +5,7 @@
 from open_feature.exception.error_code import ErrorCode
 from open_feature.exception.exceptions import OpenFeatureError
 from open_feature.flag_evaluation.reason import Reason
+from open_feature.hooks import clear_api_hooks, add_api_hooks
 from open_feature.hooks.hook import Hook
 
 
@@ -132,3 +133,19 @@ def test_should_handle_an_open_feature_exception_thrown_by_a_provider(
     assert isinstance(flag_details.value, bool)
     assert flag_details.reason == Reason.ERROR.value
     assert flag_details.error_message == "error_message"
+
+
+def test_should_call_api_level_hooks(no_op_provider_client):
+    # Given
+    clear_api_hooks()
+    api_hook = MagicMock(spec=Hook)
+    add_api_hooks([api_hook])
+
+    # When
+    no_op_provider_client.get_boolean_details(
+        flag_key="Key", default_value=True
+    )
+
+    # Then
+    api_hook.before.assert_called_once()
+    api_hook.after.assert_called_once()