Add support for filtering expected resource types

Add optional resource-types input parameter that allows specifying which AWS
resource types the stack update is expected to change. The value is passed to
CloudFormation UpdateStack API as ResourceTypes parameter.

Author: artyom

action.yml

@@ -11,6 +11,9 @@ inputs:
       Newline-separated parameters to change in the Name=Value format.
       Stack parameters not set here would retain their existing values.
     required: true
+  resource-types:
+    description: >
+      Optional newline-separated AWS resource types that stack update is expected to change.
 
 runs:
   using: docker

main.go

@@ -52,6 +52,11 @@ func run(ctx context.Context, stackName string, args []string) error {
 		return errors.New("empty parameters list")
 	}
 	debugf("loaded parameters: %v", toReplace)
+	var resourceTypes []string
+	if val := os.Getenv("INPUT_RESOURCE_TYPES"); val != "" {
+		resourceTypes = strings.Split(val, "\n")
+	}
+	debugf("resource types: %v", resourceTypes)
 	cfg, err := config.LoadDefaultConfig(ctx)
 	if err != nil {
 		return err
@@ -96,6 +101,7 @@ func run(ctx context.Context, stackName string, args []string) error {
 		ClientRequestToken:  &token,
 		UsePreviousTemplate: ptr(true),
 		Parameters:          params,
+		ResourceTypes:       resourceTypes,
 		Capabilities:        stack.Capabilities,
 		NotificationARNs:    stack.NotificationARNs,
 	})