A development team is using AWS CodeCommit to version control application code and AWS CodePipeline...

When you create a pipeline from CodePipeline during the step-by-step it creates a CloudWatch Event rule for a given branch and repo

like this:

{

"source": [

"aws.codecommit"

],

"detail-type": [

"CodeCommit Repository State Change"

],

"resources": [

"arn:aws:codecommit:us-east-1:xxxxx:repo-name"

],

"detail": {

"event": [

"referenceCreated",

"referenceUpdated"

],

"referenceType": [

"branch"

],

"referenceName": [

"master"

]

}

}

https://docs.aws.amazon.com/codepipeline/latest/userguide/pipelines-trigger-source-repo-changes-console.html