fix: separate durable async invoke flow (#8636)

* fix: separate durable async invoke flow

* test: mock durable_config to none for od async unit tests

Author: reedham-aws

samcli/local/lambda_service/local_lambda_http_service.py

@@ -274,7 +274,10 @@ def _invoke_request_handler(self, function_name):
             "function": function,
         }
 
-        if invocation_type == EVENT:
+        is_durable = function is not None and function.durable_config is not None
+
+        # Non-durable EVENT invocations run fully async
+        if invocation_type == EVENT and not is_durable:
             self.executor.submit(self._invoke_async_lambda, **arguments)
             return self.service_response("", headers, 202)
         try:
@@ -295,6 +298,10 @@ def _invoke_request_handler(self, function_name):
         if invoke_headers and isinstance(invoke_headers, dict):
             headers.update(invoke_headers)
 
+        # Durable EVENT invocations return 202 with execution ARN header but empty body
+        if is_durable and invocation_type == EVENT:
+            return self.service_response("", headers, 202)
+
         if is_lambda_user_error_response:
             headers["x-amz-function-error"] = "Unhandled"
 

tests/unit/local/lambda_service/test_local_lambda_http_service.py

@@ -414,6 +414,7 @@ def test_invoke_request_handler_async_invocation_returns_202(
         local_lambda_http_service.request = request_mock
 
         lambda_runner_mock = Mock()
+        lambda_runner_mock.get_function.return_value.durable_config = None
         lambda_runner_mock.invoke.return_value = {
             "X-Amz-Durable-Execution-Arn": "arn:aws:lambda:us-west-2:123456789012:function:test-function:$LATEST/durable-execution/test-123"
         }
@@ -492,6 +493,7 @@ def fake_invoke(*args, **kwargs):
         local_lambda_http_service.request = request_mock
 
         lambda_runner_mock = Mock()
+        lambda_runner_mock.get_function.return_value.durable_config = None
         service = LocalLambdaHttpService(lambda_runner=lambda_runner_mock, port=3000, host="localhost")
         service._invoke_lambda = fake_invoke
         service.create()
@@ -527,6 +529,7 @@ def test_invoke_request_handler_async_invocation_submits_to_executor(
         local_lambda_http_service.request = request_mock
 
         lambda_runner_mock = Mock()
+        lambda_runner_mock.get_function.return_value.durable_config = None
         service = LocalLambdaHttpService(lambda_runner=lambda_runner_mock, port=3000, host="localhost")
 
         response = service._invoke_request_handler(function_name="HelloWorld")
@@ -556,6 +559,7 @@ def test_invoke_async_lambda_logs_exceptions(self, executor_class_mock, log_mock
         local_lambda_http_service.request = request_mock
 
         lambda_runner_mock = Mock()
+        lambda_runner_mock.get_function.return_value.durable_config = None
         test_exception = Exception("Test async exception")
         lambda_runner_mock.invoke.side_effect = test_exception