Create an EventBridge rule for a CodeCommit source (CloudFormation template)

To use CloudFormation to create a rule, update your template as shown here.

To update your pipeline CloudFormation template and create EventBridge rule

1. In the template, under Resources, use the AWS::IAM::Role CloudFormation resource to configure the IAM role that allows your event to start your pipeline. This entry creates a role that uses two policies:

   • The first policy allows the role to be assumed.

   • The second policy provides permissions to start the pipeline.

   Why am I making this change? Adding the AWS::IAM::Role resource enables CloudFormation to create permissions for EventBridge. This resource is added to your CloudFormation stack.

   YAML

     EventRole:
       Type: AWS::IAM::Role
       Properties:
         AssumeRolePolicyDocument:
           Version: 2012-10-17		 	 	 
           Statement:
             -
               Effect: Allow
               Principal:
                 Service:
                   - events.amazonaws.com
               Action: sts:AssumeRole
         Path: /
         Policies:
           -
             PolicyName: eb-pipeline-execution
             PolicyDocument:
               Version: 2012-10-17		 	 	 
               Statement:
                 -
                   Effect: Allow
                   Action: codepipeline:StartPipelineExecution
                   Resource: !Join [ '', [ 'arn:aws:codepipeline:', !Ref 'AWS::Region', ':', !Ref 'AWS::AccountId', ':', !Ref AppPipeline ] ] 

   JSON

   "EventRole": {
     "Type": "AWS::IAM::Role", 
     "Properties": {
       "AssumeRolePolicyDocument": {
         "Version": "2012-10-17",		 	 	 
         "Statement": [
           {
             "Effect": "Allow",
             "Principal": {
               "Service": [
                 "events.amazonaws.com"
               ]
             },
             "Action": "sts:AssumeRole"
           }
         ]
       },
       "Path": "/",
       "Policies": [
         {
           "PolicyName": "eb-pipeline-execution",
           "PolicyDocument": {
             "Version": "2012-10-17",		 	 	 
             "Statement": [
               {
                 "Effect": "Allow",
                 "Action": "codepipeline:StartPipelineExecution",
                 "Resource": {
                   "Fn::Join": [
                     "",
                     [
                       "arn:aws:codepipeline:",
                       {
                         "Ref": "AWS::Region"
                       },
                       ":",
                       {
                         "Ref": "AWS::AccountId"
                       },
                       ":",
                       {
                         "Ref": "AppPipeline"
                       }
                     ]
   
   ...

2. In the template, under Resources, use the AWS::Events::Rule CloudFormation resource to add an EventBridge rule. This event pattern creates an event that monitors push changes to your repository. When EventBridge detects a repository state change, the rule invokes StartPipelineExecution on your target pipeline.

   Why am I making this change? Adding the AWS::Events::Rule resource enables CloudFormation to create the event. This resource is added to your CloudFormation stack.

   YAML

     EventRule:
       Type: AWS::Events::Rule
       Properties:
         EventPattern:
           source:
             - aws.codecommit
           detail-type:
             - 'CodeCommit Repository State Change'
           resources:
             - !Join [ '', [ 'arn:aws:codecommit:', !Ref 'AWS::Region', ':', !Ref 'AWS::AccountId', ':', !Ref RepositoryName ] ]
           detail:
             event:
               - referenceCreated
               - referenceUpdated
             referenceType:
               - branch
             referenceName:
               - main
         Targets:
           -
             Arn: 
               !Join [ '', [ 'arn:aws:codepipeline:', !Ref 'AWS::Region', ':', !Ref 'AWS::AccountId', ':', !Ref AppPipeline ] ]
             RoleArn: !GetAtt EventRole.Arn
             Id: codepipeline-AppPipeline

   JSON

   
   "EventRule": {
     "Type": "AWS::Events::Rule",
     "Properties": {
       "EventPattern": {
         "source": [
           "aws.codecommit"
         ],
         "detail-type": [
           "CodeCommit Repository State Change"
         ],
         "resources": [
           {
             "Fn::Join": [
               "",
               [
                 "arn:aws:codecommit:",
                 {
                   "Ref": "AWS::Region"
                 },
                 ":",
                 {
                   "Ref": "AWS::AccountId"
                 },
                 ":",
                 {
                   "Ref": "RepositoryName"
                 }
               ]
             ]
           }
         ],
         "detail": {
           "event": [
             "referenceCreated",
             "referenceUpdated"
           ],
           "referenceType": [
             "branch"
           ],
           "referenceName": [
             "main"
           ]
         }
       },
       "Targets": [
         {
           "Arn": {
             "Fn::Join": [
               "",
               [
                 "arn:aws:codepipeline:",
                 {
                   "Ref": "AWS::Region"
                 },
                 ":",
                 {
                   "Ref": "AWS::AccountId"
                 },
                 ":",
                 {
                   "Ref": "AppPipeline"
                 }
               ]
             ]
           },
           "RoleArn": {
             "Fn::GetAtt": [
               "EventRole",
               "Arn"
             ]
           },
           "Id": "codepipeline-AppPipeline"
         }
       ]
     }
   },

3. (Optional) To configure an input transformer with source overrides for a specific image ID, use the following YAML snippet. The following example configures an override where:

   • The actionName, Source in this example, is the dynamic value, defined at pipeline creation, not derived from the source event.

   • The revisionType, COMMIT_ID in this example, is the dynamic value, defined at pipeline creation, not derived from the source event.

   • The revisionValue, <revisionValue> in this example, is derived from the source event variable.

   • The output variables for BranchName and Value are specified.

   
   Rule: my-rule
   Targets:
   - Id: MyTargetId
     Arn: pipeline-ARN
     InputTransformer:
       sourceRevisions:
         actionName: Source
         revisionType: COMMIT_ID
         revisionValue: <revisionValue>
       variables:
       - name: BranchName
         value: value

4. Save the updated template to your local computer, and then open the CloudFormation console.

5. Choose your stack, and then choose Create Change Set for Current Stack.

6. Upload the template, and then view the changes listed in CloudFormation. These are the changes to be made to the stack. You should see your new resources in the list.

7. Choose Execute.

To edit your pipeline's PollForSourceChanges parameter

Important

In many cases, the PollForSourceChanges parameter defaults to true when you create a pipeline. When you add event-based change detection, you must add the parameter to your output and set it to false to disable polling. Otherwise, your pipeline starts twice for a single source change. For details, see Valid settings for the PollForSourceChanges parameter.

• In the template, change PollForSourceChanges to false. If you did not include PollForSourceChanges in your pipeline definition, add it and set it to false.

  Why am I making this change? Changing this parameter to false turns off periodic checks so you can use event-based change detection only.

  YAML

            Name: Source
            Actions: 
              - 
                Name: SourceAction
                ActionTypeId: 
                  Category: Source
                  Owner: AWS
                  Version: 1
                  Provider: CodeCommit
                OutputArtifacts: 
                  - Name: SourceOutput
                Configuration: 
                  BranchName: !Ref BranchName
                  RepositoryName: !Ref RepositoryName
                  PollForSourceChanges: false
                RunOrder: 1

  JSON

  {
    "Name": "Source", 
    "Actions": [
      {
        "Name": "SourceAction",
        "ActionTypeId": {
          "Category": "Source",
          "Owner": "AWS",
          "Version": 1,
          "Provider": "CodeCommit"
        },
        "OutputArtifacts": [
          {
            "Name": "SourceOutput"
          }
        ],
        "Configuration": {
          "BranchName": {
            "Ref": "BranchName"
          },
          "RepositoryName": {
            "Ref": "RepositoryName"
          },
          "PollForSourceChanges": false
        },
        "RunOrder": 1
      }
    ]
  },