Merge branch 'main' of github.com:awslabs/serverless-rules into main

Author: nmoutschen

cfn-lint-serverless/cfn_lint_serverless/rules/sqs.py

@@ -5,6 +5,8 @@
 
 from cfnlint.rules import CloudFormationLintRule, RuleMatch
 
+from ..utils import Value
+
 
 class SqsNoRedrivePolicyRule(CloudFormationLintRule):
     """
@@ -24,12 +26,19 @@ def match(self, cfn):
         Match against SQS queues without RedrivePolicy
         """
 
-        matches = []
+        matches = {}
+        dlqs = []
 
         for key, value in cfn.get_resources(["AWS::SQS::Queue"]).items():
             redrive_policy = value.get("Properties", {}).get("RedrivePolicy", None)
 
             if redrive_policy is None:
-                matches.append(RuleMatch(["Resources", key], self._message.format(key)))
+                matches[key] = RuleMatch(["Resources", key], self._message.format(key))
+
+            else:
+                redrive_policy = Value(redrive_policy)
+                # If a queue is used as a DLQ, it doesn't need a redrive policy
+                # See https://github.com/awslabs/serverless-rules/issues/79
+                dlqs.extend(redrive_policy.references)
 
-        return matches
+        return [v for k, v in matches.items() if k not in dlqs]

cfn-lint-serverless/tests/templates/es6000-multiple.pass.yaml

@@ -0,0 +1,15 @@
+# Test for https://github.com/awslabs/serverless-rules/issues/79
+AWSTemplateFormatVersion: "2010-09-09"
+
+Resources:
+  Queue:
+    Type: AWS::SQS::Queue
+    Properties:
+      RedrivePolicy: !Sub |
+        {
+          "deadLetterTargetArn": "${DLQ}",
+          "maxReceiveCount": 4
+        }
+
+  DLQ:
+    Type: AWS::SQS::Queue