cloudwatch alarms: how to add alarm dependency?

[clareliguori]

Version: 0.18.0

I'm running into a dependency issue creating an alarm: the alarm dimensions indirectly refer to a target group and load balancer that have not yet been created during stack creation. How do I add a dependency on these objects? There doesn't seem to be a way to add the equivalent of "DependsOn" to a construct.

Code:

   new Alarm(this, 'TargetGroupUnhealthyHosts', {
      metric: service.targetGroup.metricUnhealthyHostCount(),
      threshold: 1,
      evaluationPeriods: 2,
    });

Error:

Template error: Fn::Select  cannot select nonexistent value at index 0

Generated snippet:

      Dimensions:
        - Name: TargetGroup
          Value:
            'Fn::GetAtt':
              - ServiceLBPublicListenerECSGroup0CC8688C
              - TargetGroupFullName
        - Name: LoadBalancer
          Value:
            'Fn::Join':
              - ''
              - - 'Fn::Select':
                    - 1
                    - 'Fn::Split':
                        - /
                        - 'Fn::Select':
                            - 0
                            - 'Fn::GetAtt':
                                - ServiceLBPublicListenerECSGroup0CC8688C
                                - LoadBalancerArns
                - /
                - 'Fn::Select':
                    - 2
                    - 'Fn::Split':
                        - /
                        - 'Fn::Select':
                            - 0
                            - 'Fn::GetAtt':
                                - ServiceLBPublicListenerECSGroup0CC8688C
                                - LoadBalancerArns
                - /
                - 'Fn::Select':
                    - 3
                    - 'Fn::Split':
                        - /
                        - 'Fn::Select':
                            - 0
                            - 'Fn::GetAtt':
                                - ServiceLBPublicListenerECSGroup0CC8688C
                                - LoadBalancerArns

[rix0rrr]

It's again that association problem. Grrr.

[rix0rrr]

Ye gods this is a tricky one, too.