fix(idempotency): Correctly handle save_inprogress errors (#313)

Author: Michael Brewer

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

@@ -135,6 +135,8 @@ def handle(self) -> Any:
             # Now we know the item already exists, we can retrieve it
             record = self._get_idempotency_record()
             return self._handle_for_status(record)
+        except Exception as exc:
+            raise IdempotencyPersistenceLayerError("Failed to save in progress record to idempotency store") from exc
 
         return self._call_lambda_handler()
 

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

@@ -775,3 +775,25 @@ def test_custom_jmespath_function_overrides_builtin_functions(
         # WHEN calling _get_hashed_idempotency_key
         # THEN raise unknown function
         persistence_store._get_hashed_idempotency_key({})
+
+
+def test_idempotent_lambda_save_inprogress_error(persistence_store: DynamoDBPersistenceLayer):
+    # GIVEN a miss configured persistence layer
+    # like no table was created for the idempotency persistence layer
+    stubber = stub.Stubber(persistence_store.table.meta.client)
+    stubber.add_client_error("put_item", "ResourceNotFoundException")
+    stubber.activate()
+
+    @idempotent(persistence_store=persistence_store)
+    def lambda_handler(event, context):
+        return {}
+
+    # WHEN handling the idempotent call
+    # AND save_inprogress raises a ClientError
+    with pytest.raises(IdempotencyPersistenceLayerError) as e:
+        lambda_handler({}, {})
+
+    # THEN idempotent should raise an IdempotencyPersistenceLayerError
+    stubber.assert_no_pending_responses()
+    stubber.deactivate()
+    assert "Failed to save in progress record to idempotency store" == e.value.args[0]