Fn::If in AWS::Serverless::Function-Events

[farski]

cfn-lint version: 0.63.0

Description of issue.

I'm seeing a couple weird behaviors with Fn:If in the Events property of AWS::Serverless::Function.

When I do the following, I get a warning that IsPrimaryRegion is never used.

Conditions:
  IsPrimaryRegion: !Equals [!Ref RegionMode, Primary]

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri:
        Bucket: !Ref CodeS3Bucket
        Key: !Ref CodeS3ObjectKey
      Events:
        ScheduleTrigger:
          Properties:
            Schedule: !Sub rate(${kScheduleIntervalMinutes} ${kScheduleIntervalLabel})
            Enabled: !If [IsPrimaryRegion, true, false]
          Type: Schedule

If I change to putting the entire event in an If:

Conditions:
  IsPrimaryRegion: !Equals [!Ref RegionMode, Primary]

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri:
        Bucket: !Ref CodeS3Bucket
        Key: !Ref CodeS3ObjectKey
      Events:
        ScheduleTrigger: !If
          - IsPrimaryRegion
          - Properties:
              Schedule: !Sub rate(${kScheduleIntervalMinutes} ${kScheduleIntervalLabel})
              Enabled: true
            Type: Schedule
          - !Ref AWS::NoValue

It complains that ScheduleTrigger has no ID. (There are other Events, so that property is never empty).

[chrisoverzero]

cfn-lint is correct here: The Enabled property in SAM Schedule configuration doesn't work the way it seems like it should. I've addressed this before, but the short answer is that Enabled can't accept an intrinsic – like !If – it gets transformed to a constant ENABLED.

The SAM team has added State, which is passed through directly in the CloudFormation transformation, but I think it hasn't been released yet. SAM 1.50.0 was released 22 days ago, and that MR was merged 21 days ago. So close!

[farski]

@chrisoverzero Ah, that's an interesting gotcha. Good to know about the forthcoming State. Thanks.