fix: throw better error for improper api reference

samtranslator/plugins/api/implicit_api_plugin.py

@@ -150,6 +150,11 @@ def _process_api_events(self, function, api_events, template, condition=None):
                 raise InvalidEventException(logicalId,
                                             "Api Event must have a String specified for 'Method'.")
 
+            # !Ref is resolved by this time. If it is still a dict, we can't parse/use this Api.
+            if (isinstance(api_id, dict)):
+                raise InvalidEventException(logicalId,
+                                            "Api Event must reference an Api in the same template.")
+
             api_dict = self.api_conditions.setdefault(api_id, {})
             method_conditions = api_dict.setdefault(path, {})
             method_conditions[method] = condition

tests/plugins/api/test_implicit_api_plugin.py

@@ -447,6 +447,31 @@ def test_must_verify_method_is_string(self):
         with self.assertRaises(InvalidEventException) as context:
             self.plugin._process_api_events(function, api_events, template)
 
+    def test_must_verify_rest_api_id_is_string(self):
+        api_events = {
+            "Api1": {
+                "Type": "Api",
+                "Properties": {
+                    "Path": "/",
+                    "Method": ["POST"],
+                    "RestApiId": {"Fn::ImportValue": {"Fn::Sub": {"ApiName"}}}
+                }
+            }
+        }
+
+        template = Mock()
+        function_events_mock = Mock()
+        function = SamResource({
+            "Type": SamResourceType.Function.value,
+            "Properties": {
+                "Events": function_events_mock
+            }
+        })
+        function_events_mock.update = Mock()
+
+        with self.assertRaises(InvalidEventException) as context:
+            self.plugin._process_api_events(function, api_events, template)
+
     def test_must_verify_path_is_string(self):
         api_events = {
             "Api1": {

tests/translator/input/error_api_event_import_vaule_reference.yaml

@@ -0,0 +1,21 @@
+Parameters:
+  Api:
+    Type: String
+    Default: MyApi
+
+Resources:
+  Function:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: s3://sam-demo-bucket/member_portal.zip
+      Handler: index.gethtml
+      Runtime: nodejs4.3
+      Events:
+        GetHtml:
+          Type: Api
+          Properties:
+            Path: /
+            Method: get
+            RestApiId:
+              Fn::ImportValue:
+                Fn::Sub: ${Api}

tests/translator/output/error_api_event_import_vaule_reference.json

@@ -0,0 +1 @@
+{"errorMessage":"Invalid Serverless Application Specification document. Number of errors found: 1. Resource with id [Function] is invalid. Event with id [GetHtml] is invalid. Api Event must reference an Api in the same template."}

tests/translator/test_translator.py

@@ -548,7 +548,8 @@ def _generate_new_deployment_hash(self, logical_id, dict_to_hash, rest_api_to_sw
     'error_invalid_document_empty_semantic_version',
     'error_api_with_invalid_open_api_version_type',
     'error_api_with_custom_domains_invalid',
-    'error_api_with_custom_domains_route53_invalid'
+    'error_api_with_custom_domains_route53_invalid',
+    'error_api_event_import_vaule_reference'
 ])
 @patch('boto3.session.Session.region_name', 'ap-southeast-1')
 @patch('samtranslator.plugins.application.serverless_app_plugin.ServerlessAppPlugin._sar_service_call', mock_sar_service_call)