Add ServiceTimeout rule

The ServiceTimeout rule emits a warning if the ServiceTimeout property is not specified for a CloudFormation Custom Resource.

Author: ConnorKirk

src/cfnlint/rules/resources/cloudformation/ServiceTimeout.py

@@ -0,0 +1,57 @@
+"""
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: MIT-0
+"""
+
+from cfnlint.rules import CloudFormationLintRule
+from cfnlint.rules import RuleMatch
+
+
+class ServiceTimeout(CloudFormationLintRule):
+    """Check a ServiceTimeout property is specified for custom resources"""
+
+    id = "W3046"
+    shortdesc = "Ensure a service timeout is specified"
+    description = """
+      Custom resources should have a ServiceTimeout property specified. 
+      The default service timeout is 60 minutes. 
+      Specify a short timeout to reduce waiting if the custom resource fails 
+    """
+    source_url = "https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-cloudformation-customresource.html#cfn-cloudformation-customresource-servicetimeout"
+    tags = [
+        "resources",
+        "cloudformation",
+        "custom resource",
+    ]
+
+    def match(self, cfn):
+        """Basic Rule Matching"""
+
+        matches = []
+
+        resources = self._get_custom_resources(cfn)
+
+        for resource_name, attributes in resources.items():
+            properties = attributes.get("Properties", {})
+            resource_type = attributes.get("Type", None)
+
+            if "ServiceTimeout" not in properties:
+                message = f"Missing ServiceTimeout property in {resource_type}"
+                matches.append(RuleMatch(["Resources", resource_name], message))
+
+        return matches
+
+    def _get_custom_resources(self, cfn):
+        resources = cfn.template.get("Resources", {})
+        if not isinstance(resources, dict):
+            return {}
+
+        results = {}
+        for k, v in resources.items():
+            if isinstance(v, dict):
+                if (v.get("Type", None) == "AWS::CloudFormation::CustomResource") or (
+                    v.get("Type", None).startswith("Custom::")
+                ):
+                    results[k] = v
+
+        return results

test/fixtures/templates/bad/resources/cloudformation/service_timeout.yaml

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+Resources:
+  CustomResource:
+    Type: AWS::CloudFormation::CustomResource
+    Properties:
+      ServiceToken: "arn::aws::fake"
+  
+  CustomResource2:
+    Type: Custom::CustomResource
+    Properties:
+      ServiceToken: "arn::aws::fake"

test/fixtures/templates/good/resources/cloudformation/service_timeout.yaml

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+Resources:
+  CustomResource:
+    Type: AWS::CloudFormation::CustomResource
+    Properties:
+      ServiceToken: "arn::aws::fake"
+      ServiceTimeout: 60
+  
+  CustomResource2:
+    Type: Custom::CustomResource
+    Properties:
+      ServiceToken: "arn::aws::fake"
+      ServiceTimeout: 90

test/unit/rules/resources/cloudformation/test_service_timeout.py

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+"""
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: MIT-0
+"""
+
+import logging
+from test.unit.rules import BaseRuleTestCase
+
+from cfnlint.rules.resources.cloudformation.ServiceTimeout import (
+    ServiceTimeout,
+)
+
+
+class TestServiceTimeout(BaseRuleTestCase):
+    """Test CloudFormation Nested stack parameters"""
+
+    def tearDown(self) -> None:
+        super().tearDown()
+        logger = logging.getLogger("cfnlint.decode.decode")
+        logger.disabled = False
+
+    def setUp(self):
+        """Setup"""
+        super(ServiceTimeout, self).setUp()
+        self.collection.register(ServiceTimeout())
+        logger = logging.getLogger("cfnlint.decode.decode")
+        logger.disabled = True
+        self.success_templates = [
+            "test/fixtures/templates/good/resources/cloudformation/service_timeout.yaml"
+        ]
+
+    def test_file_positive(self):
+        """Test Positive"""
+        self.helper_file_positive()
+
+    def test_file_negative(self):
+        """Test failure"""
+        err_count = 2
+        self.helper_file_negative(
+            "test/fixtures/templates/bad/resources/cloudformation/service_timeout.yaml",
+            err_count,
+        )