Tags not applied to `AWS::Events::Rule`

[raphael-riel]

Tag not applied to AWS::Events::Rule Ressource.

Reproduction Steps

With following Stack:

import cdk = require('@aws-cdk/core');
import events = require("@aws-cdk/aws-events");

export class CdkIssueEventsRuleTagsStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const rule = new events.Rule(this, "ScheduleRule", {
      schedule: events.Schedule.rate(cdk.Duration.hours(12)),
      targets: []
    });

    cdk.Tag.add(rule, "MyTag", "ThatValue");
  }
}

Synthesized template is:

Resources:
  ScheduleRuleDA5BD877:
    Type: AWS::Events::Rule
    Properties:
      ScheduleExpression: rate(12 hours)
      State: ENABLED
    Metadata:
      aws:cdk:path: CdkIssueEventsRuleTagsStack/ScheduleRule/Resource
  CDKMetadata:
    Type: AWS::CDK::Metadata
    Properties:
      Modules: aws-cdk=1.15.0,@aws-cdk/aws-events=1.15.0,@aws-cdk/core=1.15.0,@aws-cdk/cx-api=1.15.0,jsii-runtime=node.js/v12.12.0
    Condition: CDKMetadataAvailable

[...]

In console, the Tags are available.

Environment

Using CDK 1.15.0

---

This is 🐛 Bug Report

[raphael-riel]

While writing the report, I've seen that it seems to be CloudFormation that doesn't support Tags for this kind of Ressource.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-rule.html

Should a Ressource that doesn't support Tags emit some sort of WARN or raises when we try to apply Tags to it?

[rix0rrr]

Because we assign tags recursively to all constructs in a scope it really doesn't make much sense to warn for constructs that don't support it. You would get a deluge of warnings if you apply tags at a high level.

We will have to wait for CloudFormation support.

[raphael-riel]

@rix0rrr I totally agree!

In my specific case, I explicitly attempt to add the Tag on the invalid Construct; it's in no way recursive.
Could a quick-win be to somehow only check at the initial cdk.Tag.add() invocation?

Or could there be two add, one public for the explicit call, and one internal for recursive calls?
This way the Constructs classes could get a proper ITaggeable type and benefit from compile-time checking ?

Cause in the end, there's always be some stuff not supported in CloudFormation, and reflecting those in my IDE while coding (IntelliSense) would greatly help! (The main reason I love so much working with the CDK!)

What do you think of the proposal/brainstorm above?

Thanks!