Add simple poc tests for event callbacks.

.devcontainer/post_install.sh

@@ -2,11 +2,7 @@
 set -ex
 
 # Install package
-sudo python -m venv .venv
-source .venv/bin/activate
-pip install -U -r requirements.txt
-python setup.py install
-./get-spec.sh
+sudo su - vscode bash -c "cd /workspaces/unleash-client-python; python -m venv .venv; source .venv/bin/activate; pip install -U -r requirements.txt; python setup.py install; ./get-spec.sh;"
 
 # Install pre-config
 # pip install pre-commit

UnleashClient/__init__.py

@@ -47,7 +47,7 @@ class UnleashClient:
     :param scheduler: Custom APScheduler object.  Use this if you want to customize jobstore or executors.  When unset, UnleashClient will create it's own scheduler.
     :param scheduler_executor: Name of APSCheduler executor to use if using a custom scheduler.
     :param multiple_instance_mode: Determines how multiple instances being instantiated is handled by the SDK, when set to InstanceAllowType.BLOCK, the client constructor will fail when more than one instance is detected, when set to InstanceAllowType.WARN, multiple instances will be allowed but log a warning, when set to InstanceAllowType.SILENTLY_ALLOW, no warning or failure will be raised when instantiating multiple instances of the client. Defaults to InstanceAllowType.WARN
-    :param event_callback: Function to call if impression events are enabled.
+    :param event_callback: Function to call if impression events are enabled.  WARNING: Depending on your event library, this may have performance implications!
     """
     def __init__(self,
                  url: str,
@@ -302,16 +302,20 @@ def is_enabled(self,
                 feature = self.features[feature_name]
                 feature_check = feature.is_enabled(context)
 
-                if self.unleash_event_callback and feature.impression_data:
-                    event = UnleashEvent(
-                        event_type=UnleashEventType.FEATURE_FLAG,
-                        event_id=uuid.uuid1(),
-                        context=context,
-                        enabled=feature_check,
-                        feature_name=feature_name
-                    )
-
-                    self.unleash_event_callback(event)
+                try:
+                    if self.unleash_event_callback and feature.impression_data:
+                        event = UnleashEvent(
+                            event_type=UnleashEventType.FEATURE_FLAG,
+                            event_id=uuid.uuid4(),
+                            context=context,
+                            enabled=feature_check,
+                            feature_name=feature_name
+                        )
+
+                        self.unleash_event_callback(event)
+                except Exception as excep:
+                    LOGGER.log(self.unleash_verbose_log_level, "Error in event callback: %s", excep)
+                    return feature_check
 
                 return feature_check
             except Exception as excep:
@@ -347,16 +351,20 @@ def get_variant(self,
                 variant_check = feature.get_variant(context)
 
                 if self.unleash_event_callback and feature.impression_data:
-                    event = UnleashEvent(
-                        event_type=UnleashEventType.VARIANT,
-                        event_id=uuid.uuid1(),
-                        context=context,
-                        enabled=variant_check['enabled'],
-                        feature_name=feature_name,
-                        variant=variant_check['enabled']
-                    )
-
-                    self.unleash_event_callback(event)
+                    try:
+                        event = UnleashEvent(
+                            event_type=UnleashEventType.VARIANT,
+                            event_id=uuid.uuid4(),
+                            context=context,
+                            enabled=variant_check['enabled'],
+                            feature_name=feature_name,
+                            variant=variant_check['name']
+                        )
+
+                        self.unleash_event_callback(event)
+                    except Exception as excep:
+                        LOGGER.log(self.unleash_verbose_log_level, "Error in event callback: %s", excep)
+                        return variant_check
 
                 return variant_check
             except Exception as excep:

UnleashClient/api/features.py

@@ -61,7 +61,7 @@ def get_feature_toggles(url: str,
         if resp.status_code not in [200, 304]:
             log_resp_info(resp)
             LOGGER.warning("Unleash Client feature fetch failed due to unexpected HTTP status code.")
-            raise Exception("Unleash Client feature fetch failed!") # pylint: disable=broad-exception-raised
+            raise Exception("Unleash Client feature fetch failed!")  # pylint: disable=broad-exception-raised
 
         etag = ''
         if 'etag' in resp.headers.keys():

requirements.txt

@@ -31,3 +31,4 @@ m2r2
 tox
 types-requests
 twine
+blinker

tests/unit_tests/test_client.py

@@ -7,6 +7,8 @@
 import responses
 from apscheduler.schedulers.background import BackgroundScheduler
 from apscheduler.executors.pool import ThreadPoolExecutor
+from blinker import signal
+
 from UnleashClient import UnleashClient, INSTANCES
 from UnleashClient.strategies import Strategy
 from UnleashClient.utils import InstanceAllowType
@@ -17,6 +19,7 @@
 from tests.utilities.mocks.mock_all_features import MOCK_ALL_FEATURES
 from UnleashClient.constants import REGISTER_URL, FEATURES_URL, METRICS_URL
 from UnleashClient.cache import FileCache
+from UnleashClient.events import UnleashEvent, UnleashEventType
 
 
 class EnvironmentStrategy(Strategy):
@@ -574,3 +577,48 @@ def test_multiple_instances_are_unique_on_api_key(caplog):
     UnleashClient(URL, "some-probably-unique-app-name", custom_headers={"Authorization": "penguins"})
     UnleashClient(URL, "some-probably-unique-app-name", custom_headers={"Authorization": "hamsters"})
     assert not all(["Multiple instances has been disabled" in r.msg for r in caplog.records])
+
+@responses.activate
+def test_signals_feature_flag(cache):
+    # Set up API
+    responses.add(responses.POST, URL + REGISTER_URL, json={}, status=202)
+    responses.add(responses.GET, URL + FEATURES_URL, json=MOCK_FEATURE_RESPONSE, status=200)
+    responses.add(responses.POST, URL + METRICS_URL, json={}, status=202)
+
+    # Set up signals
+    send_data = signal('send-data')
+
+    @send_data.connect
+    def receive_data(sender, **kw):
+        print("Caught signal from %r, data %r" % (sender, kw))
+
+        if kw['data'].event_type == UnleashEventType.FEATURE_FLAG:
+            assert kw['data'].feature_name == 'testFlag'
+            assert kw['data'].enabled == True
+        elif kw['data'].event_type == UnleashEventType.VARIANT:
+            assert kw['data'].feature_name == 'testVariations'
+            assert kw['data'].enabled == True
+            assert kw['data'].variant == 'VarA'
+
+        raise Exception("Random!")
+
+    def example_callback(event: UnleashEvent):
+        send_data.send('anonymous', data=event)
+
+    # Set up Unleash
+    unleash_client = UnleashClient(
+        URL,
+        APP_NAME,
+        refresh_interval=REFRESH_INTERVAL,
+        metrics_interval=METRICS_INTERVAL,
+        cache=cache,
+        event_callback=example_callback
+    )
+
+    # Create Unleash client and check initial load
+    unleash_client.initialize_client()
+    time.sleep(1)
+
+    assert unleash_client.is_enabled("testFlag")
+    variant = unleash_client.get_variant("testVariations", context={'userId': '2'})
+    assert variant['name'] == 'VarA'

tests/utilities/mocks/mock_features.py

@@ -12,7 +12,7 @@
                 }
             ],
             "createdAt": "2018-10-04T01:27:28.477Z",
-            "impressionData": False
+            "impressionData": True
         },
         {
             "name": "testFlag2",
@@ -113,7 +113,7 @@
                 }
             ],
             "createdAt": "2019-10-25T13:22:02.035Z",
-            "impressionData": False
+            "impressionData": True
         }
     ]
 }