Example: Create a trigger in AWS CodeCommit for an existing AWS Lambda function

Open a plain-text editor and create a JSON file that specifies the Lambda function name, the details of the CodeCommit repository, and the actions you want to allow in Lambda, similar to the following:

{
    "FunctionName": "MyCodeCommitFunction", 
    "StatementId": "1", 
    "Action": "lambda:InvokeFunction", 
    "Principal": "codecommit.amazonaws.com", 
    "SourceArn": "arn:aws:codecommit:us-east-1:111122223333:MyDemoRepo", 
    "SourceAccount": "111122223333"
}

Save the file as a JSON file with a name that is easy for you to remember (for example, AllowAccessfromMyDemoRepo.json).

Using the JSON file you just created, at the terminal (Linux, macOS, or Unix) or command line (Windows), run the aws lambda add-permissions command to add a permission to the resource policy associated with your Lambda function:

aws lambda add-permission --cli-input-json file://AllowAccessfromMyDemoRepo.json

This command returns the JSON of the policy statement you just added, similar to the following:

{
    "Statement": "{\"Condition\":{\"StringEquals\":{\"AWS:SourceAccount\":\"111122223333\"},\"ArnLike\":{\"AWS:SourceArn\":\"arn:aws:codecommit:us-east-1:111122223333:MyDemoRepo\"}},\"Action\":[\"lambda:InvokeFunction\"],\"Resource\":\"arn:aws:lambda:us-east-1:111122223333:function:MyCodeCommitFunction\",\"Effect\":\"Allow\",\"Principal\":{\"Service\":\"codecommit.amazonaws.com\"},\"Sid\":\"1\"}"
}

For more information about resource policies for Lambda functions, see AddPermission and The Pull/Push Event Models in the AWS Lambda User Guide.

Sign in to the AWS Management Console and open the IAM console at https://console.aws.amazon.com/iam/.

In the Dashboard navigation pane, choose Roles, and in the list of roles, select lambda_basic_execution.

On the summary page for the role, choose the Permissions tab, and in Inline Policies, choose Create Role Policy.

On the Set Permissions page, choose Policy Generator, and then choose Select.

On the Edit Permissions page, do the following:

Choose Add Statement, and then choose Next Step.

On the Review Policy page, choose Apply Policy.

Your policy statement should look similar to the following example:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt11111111",
            "Effect": "Allow",
            "Action": [
                "codecommit:GetRepository"
            ],
            "Resource": [
                "arn:aws:codecommit:us-east-1:111122223333:MyDemoRepo"
            ]
        }
    ]
}

Open the CodeCommit console at https://console.aws.amazon.com/codesuite/codecommit/home.

In Repositories, choose the repository where you want to create triggers for repository events.

In the navigation pane for the repository, choose Settings, and then choose Triggers.

Choose Create trigger.

In Create trigger, do the following:

(Optional) Choose Test trigger. This option attempts to invoke the function with sample data about your repository, including the most recent commit ID for the repository. (If no commit history exists, sample values consisting of zeroes are generated instead.) This helps you confirm that you have correctly configured access between CodeCommit and the Lambda function.

Choose Create trigger to finish creating the trigger.

To verify the functionality of the trigger, make and push a commit to the repository where you configured the trigger. You should see a response from the Lambda function on the Monitoring tab for that function in the Lambda console.

Open a plain-text editor and create a JSON file that specifies:

Save the file.

For example, if you want to create a trigger for a repository named MyDemoRepo that publishes all repository events to a Lambda function named MyCodeCommitFunction for two branches, main and preprod:

{
    "repositoryName": "MyDemoRepo",
    "triggers": [
        {
            "name": "MyLambdaFunctionTrigger",
            "destinationArn": "arn:aws:lambda:us-east-1:111122223333:function:MyCodeCommitFunction",
            "customData": "",
            "branches": [
                "main", "preprod"
            ],
            "events": [
                "all"
            ]
        }
    ]
}

There must be a trigger block in the JSON for each trigger for a repository. To create more than one trigger for a repository, include additional blocks in the JSON. Remember that all triggers created in this file are for the specified repository. You cannot create triggers for multiple repositories in a single JSON file. For example, if you wanted to create two triggers for a repository, you can create a JSON file with two trigger blocks. In the following example, no branches are specified in the second trigger block, so that trigger applies to all branches:

{
    "repositoryName": "MyDemoRepo",
    "triggers": [
        {
            "name": "MyLambdaFunctionTrigger",
            "destinationArn": "arn:aws:lambda:us-east-1:111122223333:function:MyCodeCommitFunction",
            "customData": "",
            "branches": [
                "main", "preprod"
            ],
            "events": [
                "all"
            ]
        },
        {
            "name": "MyOtherLambdaFunctionTrigger",
            "destinationArn": "arn:aws:lambda:us-east-1:111122223333:function:MyOtherCodeCommitFunction",
            "customData": "",
            "branches": [],
            "events": [
                "updateReference", "deleteReference"
            ]
        }
    ]
}

You can create triggers for events you specify, such as when a commit is pushed to a repository. Event types include:

To see the full list of valid event types, at the terminal or command prompt, enter aws codecommit put-repository-triggers help.

In addition, you can include a string in customData (for example, an IRC channel name developers use when discussing development in this repository). This field is a string. It cannot be used to pass any dynamic parameters. This string is appended as an attribute to the CodeCommit JSON returned in response to the trigger.

(Optional) At a terminal or command prompt, run the test-repository-triggers command. For example, the following is used to test that the JSON file named trigger.json is valid and that CodeCommit can trigger the Lambda function. This test uses sample data to trigger the function if no real data is available.

aws codecommit test-repository-triggers --cli-input-json file://trigger.json

If successful, this command returns information similar to the following:

{
    "successfulExecutions": [
        "MyLambdaFunctionTrigger"
    ],
    "failedExecutions": []
}

At a terminal or command prompt, run the put-repository-triggers command to create the trigger in CodeCommit. For example, to use a JSON file named trigger.json to create the trigger:

aws codecommit put-repository-triggers --cli-input-json file://trigger.json

This command returns a configuration ID, similar to the following:

{
    "configurationId": "0123456-I-AM-AN-EXAMPLE"
}

To view the configuration of the trigger, run the get-repository-triggers command, specifying the name of the repository:

aws codecommit get-repository-triggers --repository-name MyDemoRepo

This command returns the structure of all triggers configured for the repository, similar to the following:

{
    "configurationId": "0123456-I-AM-AN-EXAMPLE",
    "triggers": [
        {
            "events": [
                "all"
            ],
            "destinationArn": "arn:aws:lambda:us-east-1:111122223333:MyCodeCommitFunction",
            "branches": [
                "main",
                "preprod"
            ],
            "name": "MyLambdaFunctionTrigger",
            "customData": "Project ID 12345"
        }
    ]
}

To test the functionality of the trigger, make and push a commit to the repository where you configured the trigger. You should see a response from the Lambda function on the Monitoring tab for that function in the Lambda console.