feat(idempotencty): Raise error when event data is None

GIVEN a persistence_store with event_key_jmespath = `body`
WHEN getting the hashed idempotency key with an event without a `body` key
THEN raise IdempotencyValidationError

Author: Michael Brewer

Diff for: aws_lambda_powertools/utilities/idempotency/persistence/base.py

@@ -162,6 +162,10 @@ def _get_hashed_idempotency_key(self, lambda_event: Dict[str, Any]) -> str:
         data = lambda_event
         if self.event_key_jmespath:
             data = self.event_key_compiled_jmespath.search(lambda_event)
+
+        if data is None:
+            raise IdempotencyValidationError("No data found to create a hashed idempotency_key")
+
         return self._generate_hash(data)
 
     def _get_hashed_payload(self, lambda_event: Dict[str, Any]) -> str:

Diff for: tests/functional/idempotency/conftest.py

@@ -152,7 +152,7 @@ def hashed_validation_key(lambda_apigw_event):
 @pytest.fixture
 def persistence_store(config, request, default_jmespath):
     persistence_store = DynamoDBPersistenceLayer(
-        event_key_jmespath=default_jmespath,
+        event_key_jmespath=request.param.get("event_key_jmespath") or default_jmespath,
         table_name=TABLE_NAME,
         boto_config=config,
         use_local_cache=request.param["use_local_cache"],

Diff for: tests/functional/idempotency/test_idempotency.py

@@ -627,3 +627,17 @@ def test_user_local_disabled(persistence_store):
     # THEN raise AttributeError
     # AND don't have a _cache attribute
     assert not hasattr("persistence_store", "_cache")
+
+
+@pytest.mark.parametrize("persistence_store", [{"use_local_cache": False, "event_key_jmespath": "body"}], indirect=True)
+def test_no_data_for_generate_hash(persistence_store):
+    # GIVEN a persistence_store with use_local_cache = False and event_key_jmespath = "body"
+    assert persistence_store.use_local_cache is False
+    assert "body" in persistence_store.event_key_jmespath
+
+    # WHEN getting the hashed idempotency key for an event with no `body` key
+    with pytest.raises(IdempotencyValidationError) as excinfo:
+        persistence_store._get_hashed_idempotency_key({})
+
+    # THEN raise IdempotencyValidationError error
+    assert "No data found to create a hashed idempotency_key" in str(excinfo.value)