Notify on Event

The Notify on Event action notifies you of selected CloudTrail events.

Use of this action in a rule

The Notify on Event action must always be used in a rule with the CloudTrail Event trigger, which takes responsibility for sourcing selected events from your CloudTrail logs.

Turning events into notifications

Provide JMSEPath expressions to pluck values from your CloudTrail events. For example, the following expressions pluck key values from an UpdateAutoScalingGroup event.

JMSEPath expressions

Don’t worry about any <no-value> messages that you might see. They just mean that the sample event currently loaded in the Example Event box in the Notify on Event action screen does not contain any values that match your JMSEPath Expressions. However, you can replace any <no-value> messages with actual results by pasting an actual event of the desired type into the Example Box. For example, an UpdateAutoScalingGroup event like this one was loaded when creating the mappings shown above:

  "eventInfo": {
    "sourceEvent": {
      "detail-type": "AWS API Call via CloudTrail",
      "source": "aws.autoscaling",
      "detail": {
        "requestParameters": {
          "maxSize": 4,
          "minSize": 2,
          "desiredCapacity": 3,
          "autoScalingGroupName": "test-existing-asg-settings",
    "source": "aws-cloudwatch"

To find examples of real events that have occurred in your own AWS account, log into CloudTrail in the AWS Console, then click Event History.

Once you have saved the rule and AWS generates a matching CloudWatch event, you will receive a notification that looks like this:

Example Slack notification