Fix an issue with W1011 to allow integers in the FindInMap (#3272)

Author: kddejong

src/cfnlint/rules/functions/FindInMapKeys.py

@@ -28,6 +28,7 @@ def check_keys(self, map_name, keys, mappings, tree, cfn):
                 mapping = mappings.get(map_name)
                 if mapping:
                     if isinstance(first_key, (str, int)):
+                        first_key = str(first_key)
                         if isinstance(map_name, (str)):
                             if mapping.get(first_key) is None:
                                 message = 'FindInMap first key "{0}" doesn\'t exist in map "{1}" at {3}'
@@ -44,6 +45,7 @@ def check_keys(self, map_name, keys, mappings, tree, cfn):
                                 )
                         if mapping.get(first_key):
                             # Don't double error if they first key doesn't exist
+                            second_key = str(second_key)
                             if mapping.get(first_key, {}).get(second_key) is None:
                                 message = 'FindInMap second key "{0}" doesn\'t exist in map "{1}" under "{2}" at {3}'
                                 matches.append(

test/fixtures/templates/good/functions/findinmap_keys.yaml

@@ -4,8 +4,10 @@ Mappings:
   CertificateMap:
     us-east-1:
       Arn: arn:aws:acm:us-east-1:<account>:certificate/<id>
-    2:
+    "2":
       Arn: "" # Empty string is a valid value
+    key:
+      3: "" # Empty string is a valid value
 Resources:
   AppAlbListener:
     Type: AWS::ElasticLoadBalancingV2::Listener
@@ -32,3 +34,9 @@ Resources:
       Certificates:
         - CertificateArn:  # Doesn't fail with integer
             Fn::FindInMap: [!Ref 'AWS::Region', 2, id]
+  AppAlbListener4:
+    Type: AWS::ElasticLoadBalancingV2::Listener
+    Properties:
+      Certificates:
+        - CertificateArn:  # Doesn't fail with integer
+            Fn::FindInMap: [!Ref 'AWS::Region', key, 3]