如何对违反特定阈值的 EventBridge 规则数量创建警报？

Question

I have a system that auto creates and deletes CloudWatch Rules but there is a hard limit of 300 rules in every Event Bus. I want to create an alarm that gets triggered whenever a certain number, say 100, is reached. How can I do that using CDK code?

Answer 1

Create a Lambda function that calls the ListRules API. The Lambda counts the rules. Have EventBridge trigger the Lambda periodically with a scheduled Rule . If you want an Alarm, your Lambda could write the rule count to CloudWatch as a custom metric and configure an Alarm to monitor it. A simpler option is to have the Lambda put an SNS notification to a Topic if the rule count exceeds 100.

To recap, the CDK constructs would be: a Lambda Function , an EventBridge Rule and a CloudWatch Alarm (or SNS Topic and Subscription ).