Skip getatt validation with custom resources (#3346)

* Add exceptions for getatt format type
aws-cloudformation · Jun 20, 2024 · 41a17e3 · 41a17e3
1 parent 4c3a445
commit 41a17e3
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Showing 2 changed files with 21 additions and 0 deletions.
diff --git a/src/cfnlint/rules/functions/GetAttFormat.py b/src/cfnlint/rules/functions/GetAttFormat.py
@@ -27,6 +27,10 @@ def __init__(self):
             "AWS::EC2::SecurityGroup.GroupId",
             "AWS::EC2::SecurityGroup.GroupIds",
         ]
+        self._resource_type_exceptions = [
+            "AWS::CloudFormation::CustomResource",
+            "AWS::CloudFormation::Stack",
+        ]
 
     def validate(
         self, validator: Validator, _, instance: Any, schema: Any
@@ -40,6 +44,9 @@ def validate(
         getatt_ptr = validator.context.resources[resource].get_atts[attr]
         t = validator.context.resources[resource].type
 
+        if t in self._resource_type_exceptions:
+            return
+
         for (
             _,
             resource_schema,

diff --git a/test/unit/rules/functions/test_getatt_format.py b/test/unit/rules/functions/test_getatt_format.py
@@ -22,6 +22,8 @@ def template():
             "MyBucket": {"Type": "AWS::S3::Bucket"},
             "MyVpc": {"Type": "AWS::EC2::VPC"},
             "MySecurityGroup": {"Type": "AWS::EC2::SecurityGroup"},
+            "MyCustomResource": {"Type": "Custom::CustomResource"},
+            "MySubTemplate": {"Type": "AWS::CloudFormation::Stack"},
         },
     }
 
@@ -35,6 +37,18 @@ def template():
             {"format": "AWS::EC2::VPC.Id"},
             [],
         ),
+        (
+            "Valid GetAtt to a custom resource",
+            ["MyCustomResource", "ImageId"],
+            {"format": "AWS::EC2::VPC.Id"},
+            [],
+        ),
+        (
+            "Valid GetAtt to a sub template ",
+            ["MySubTemplate", "Outputs.ImageId"],
+            {"format": "AWS::EC2::VPC.Id"},
+            [],
+        ),
         (
             "Valid GetAtt because of exception",
             ["MyBucket", "Arn"],