fix: Avoid crashing on invalid function name (#7392)

* fix: Avoid crashing on invalid function name

* Remove unused exception

samcli/lib/providers/exceptions.py

@@ -83,3 +83,12 @@ def resource_identifier(self) -> "ResourceIdentifier":
     @property
     def property_name(self) -> str:
         return self._property_name
+
+
+class MissingFunctionNameException(Exception):
+    """
+    Exception when a resource does not have function name specified
+    """
+
+    def __init__(self) -> None:
+        super().__init__("Unable to get Lambda function because the function identifier is not defined.")

samcli/lib/providers/sam_function_provider.py

@@ -11,7 +11,7 @@
 from samcli.commands._utils.template import TemplateFailedParsingException
 from samcli.commands.local.cli_common.user_exceptions import InvalidLayerVersionArn
 from samcli.lib.build.exceptions import MissingFunctionHandlerException
-from samcli.lib.providers.exceptions import InvalidLayerReference
+from samcli.lib.providers.exceptions import InvalidLayerReference, MissingFunctionNameException
 from samcli.lib.utils.colors import Colored, Colors
 from samcli.lib.utils.file_observer import FileObserver
 from samcli.lib.utils.packagetype import IMAGE, ZIP
@@ -119,7 +119,8 @@ def get(self, name: str) -> Optional[Function]:
         """
 
         if not name:
-            raise ValueError("Function name is required")
+            LOG.debug("Function name is not defined, unable to fetch Lambda function.")
+            raise MissingFunctionNameException()
 
         resolved_function = None
 

samcli/local/apigw/local_apigw_service.py

@@ -15,6 +15,7 @@
 
 from samcli.commands.local.lib.exceptions import UnsupportedInlineCodeError
 from samcli.commands.local.lib.local_lambda import LocalLambdaRunner
+from samcli.lib.providers.exceptions import MissingFunctionNameException
 from samcli.lib.providers.provider import Api, Cors
 from samcli.lib.telemetry.event import EventName, EventTracker, UsedFeature
 from samcli.lib.utils.stream_writer import StreamWriter
@@ -733,6 +734,10 @@ def _request_handler(self, **kwargs):
             endpoint_service_error = ServiceErrorResponses.lambda_body_failure_response()
         except DockerContainerCreationFailedException as ex:
             endpoint_service_error = ServiceErrorResponses.container_creation_failed(ex.message)
+        except MissingFunctionNameException as ex:
+            endpoint_service_error = ServiceErrorResponses.lambda_failure_response(
+                f"Failed to execute endpoint. Got an invalid function name ({str(ex)})",
+            )
 
         if endpoint_service_error:
             return endpoint_service_error

tests/unit/commands/local/lib/test_sam_function_provider.py

@@ -11,7 +11,7 @@
 from samcli.commands.local.cli_common.user_exceptions import InvalidLayerVersionArn
 from samcli.lib.providers.provider import Function, LayerVersion, Stack, FunctionBuildInfo
 from samcli.lib.providers.sam_function_provider import SamFunctionProvider, RefreshableSamFunctionProvider
-from samcli.lib.providers.exceptions import InvalidLayerReference
+from samcli.lib.providers.exceptions import InvalidLayerReference, MissingFunctionNameException
 from samcli.lib.utils.packagetype import IMAGE, ZIP
 
 
@@ -1908,7 +1908,7 @@ class TestSamFunctionProvider_get(TestCase):
     def test_raise_on_invalid_name(self):
         provider = SamFunctionProvider([])
 
-        with self.assertRaises(ValueError):
+        with self.assertRaises(MissingFunctionNameException):
             provider.get(None)
 
     def test_must_return_function_value(self):

tests/unit/local/apigw/test_local_apigw_service.py

@@ -8,6 +8,7 @@
 from parameterized import parameterized, param
 from werkzeug.datastructures import Headers
 
+from samcli.lib.providers.exceptions import MissingFunctionNameException
 from samcli.lib.providers.provider import Api
 from samcli.lib.providers.provider import Cors
 from samcli.lib.telemetry.event import EventName, EventTracker, UsedFeature
@@ -23,6 +24,7 @@
     LambdaResponseParseException,
     PayloadFormatVersionValidateException,
 )
+from samcli.local.apigw.service_error_responses import ServiceErrorResponses
 from samcli.local.docker.exceptions import DockerContainerCreationFailedException
 from samcli.local.lambdafn.exceptions import FunctionNotFound
 from samcli.commands.local.lib.exceptions import UnsupportedInlineCodeError
@@ -1040,6 +1042,47 @@ def test_authorizer_function_not_found_invokes_endpoint(
             self.api_gateway_route.function_name, ANY, stdout=ANY, stderr=self.stderr
         )
 
+    @patch.object(LocalApigwService, "get_request_methods_endpoints")
+    @patch.object(LocalApigwService, "_generate_lambda_authorizer_event")
+    @patch.object(LocalApigwService, "_valid_identity_sources")
+    @patch.object(LocalApigwService, "_invoke_lambda_function")
+    @patch.object(LocalApigwService, "_invoke_parse_lambda_authorizer")
+    @patch.object(EventTracker, "track_event")
+    @patch("samcli.local.apigw.local_apigw_service.construct_v1_event")
+    @patch("samcli.local.apigw.local_apigw_service.construct_v2_event_http")
+    @patch("samcli.local.apigw.local_apigw_service.ServiceErrorResponses")
+    def test_lambda_invoke_fails_no_function_name_exception(
+        self,
+        service_mock,
+        v2_event_mock,
+        v1_event_mock,
+        track_mock,
+        lambda_invoke_mock,
+        invoke_mock,
+        validate_id_mock,
+        gen_auth_event_mock,
+        request_mock,
+    ):
+        self.api_service._get_current_route = MagicMock()
+
+        self.api_gateway_route.authorizer_object = Mock()
+
+        self.api_service._get_current_route.return_value = self.api_gateway_route
+        self.api_service._get_current_route.methods = []
+        self.api_service._get_current_route.return_value.payload_format_version = "2.0"
+
+        invoke_mock.side_effect = MissingFunctionNameException()
+        service_mock.lambda_failure_response = Mock()
+        request_mock.return_value = ("test", "test")
+        v1_event_mock.return_value = {}
+
+        self.api_service._request_handler()
+
+        service_mock.lambda_failure_response.assert_called_once_with(
+            "Failed to execute endpoint. Got an invalid function name "
+            "(Unable to get Lambda function because the function identifier is not defined.)"
+        )
+
 
 class TestApiGatewayModel(TestCase):
     def setUp(self):