​​How to send repeated notifications for CloudWatch Alarms: h | AWS Notes

​​How to send repeated notifications for CloudWatch Alarms:

https://aws.amazon.com/blogs/mt/how-to-enable-amazon-cloudwatch-alarms-to-send-repeated-notifications/

CloudWatch alarm is triggered and goes into the ALARM state.
CloudWatch alarm sends the first alarm notification to the associated SNS alarm actions.
CloudWatch Alarms service sends an alarm state change event which triggers the EventBridge rule.
With a match event, the EventBridge rule invokes the Step Function target.
Once the Step Function starts execution, it first enters a Wait state.
The Step Function enters the Lambda Invocation task. The Lambda invocation task:
Checks if the alarm has the specific tag key and value (e.g., RepeatedAlarm:true). If not, the function exits
Checks the alarm’s current state by performing a DescribeAlarms API with the alarm name.
Publishes the existing alarm’s status returned from the DescribeAlarms API call to all the SNS topics subscribed on the alarm
Returns the alarm’s current state together with the original received event back to the Step Function.
The Choice state checks the alarm state returned by the Lambda function and directs the workflow to go back to the Wait state if the alarm state is ‘ALARM’ otherwise it ends the step function’s execution.
The repeated notification for an alarm within the workflow above stops when:
The alarm transitions to a non-ALARM state.
The alarm is deleted.
A specific tag is removed from the alarm.

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