Manually configure permissions to allow CodeCommit to run a Lambda function Create a trigger for the Lambda function in a CodeCommit repository (console)Create a trigger to a Lambda function for a CodeCommit repository (AWS CLI)

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

The easiest way to create a trigger that invokes a Lambda function is to create that trigger in the Lambda console. This built-in integration ensures that CodeCommit has the permissions required to run the function. To add a trigger for an existing Lambda function, go to the Lambda console, and choose the function. On the Triggers tab for the function, follow the steps in Add trigger. These steps are similar to the ones in Create the Lambda function.

You can also create a trigger for a Lambda function in a CodeCommit repository. Doing so requires that you choose an existing Lambda function to invoke. It also requires that you manually configure the permissions required for CodeCommit to run the function.

Topics

Manually configure permissions to allow CodeCommit to run a Lambda function
Create a trigger for the Lambda function in a CodeCommit repository (console)
Create a trigger to a Lambda function for a CodeCommit repository (AWS CLI)

Manually configure permissions to allow CodeCommit to run a Lambda function

If you create a trigger in CodeCommit that invokes a Lambda function, you must manually configure the permissions that allow CodeCommit to run the Lambda function. To avoid this manual configuration, consider creating the trigger for the function in the Lambda console instead.

To allow CodeCommit to run a 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:
- In Effect, choose Allow.
- In AWS Service, choose AWS CodeCommit.
- In Actions, select GetRepository.
- In Amazon Resource Name (ARN), enter the ARN for the repository (for example, arn:aws:codecommit:us-east-1:111122223333:MyDemoRepo).
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"
            ]
        }
    ]
}

Create a trigger for the Lambda function in a CodeCommit repository (console)

After you have created the Lambda function, you can create a trigger in CodeCommit that runs the function in response to the repository events you specify.

Note

Before you can successfully test or run the trigger for the example, you must configure the policies that allow CodeCommit to invoke the function and the Lambda function to get information about the repository. For more information, see To allow CodeCommit to run a Lambda function.

To create a trigger for a Lambda function

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:
- In Trigger name, enter a name for the trigger (for example, MyLambdaFunctionTrigger).
- In Events, choose the repository events that trigger the Lambda function.
  
  If you choose All repository events, you cannot choose any other events. If you want to choose a subset of events, clear All repository events, and then choose the events you want from the list. For example, if you want the trigger to run only when a user creates a tag or a branch in the CodeCommit repository, remove All repository events, and then choose Create branch or tag.
- If you want the trigger to apply to all branches of the repository, in Branches, leave the selection blank, because this default option applies the trigger to all branches automatically. If you want this trigger to apply to specific branches only, choose up to 10 branch names from the list of repository branches.
- In Choose the service to use, choose AWS Lambda.
- In Lambda function, choose the function name from the list, or enter the ARN for the function.
- (Optional) In Custom data, enter information you want included in the Lambda function (for example, the name of the IRC channel used by developers to discuss development in the repository). This field is a string. It cannot be used to pass any dynamic parameters.
(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.

Create a trigger to a Lambda function for a CodeCommit repository (AWS CLI)

You can also use the command line to create a trigger for a Lambda function in response to CodeCommit repository events, such as when someone pushes a commit to your repository.

To create a trigger for an Lambda function

Open a plain-text editor and create a JSON file that specifies:
- The Lambda function name.
- The repository and branches you want to monitor with this trigger. (If you do not specify any branches, the trigger applies to all branches in the repository.)
- The events that activate this trigger.
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:
- all for all events in the specified repository and branches.
- updateReference for when commits are pushed to the specified repository and branches.
- createReference for when a new branch or tag is created in the specified repository.
- deleteReference for when a branch or tag is deleted in the specified repository.
Note
You can use more than one event type in a trigger. However, if you specify all, you cannot specify other events.

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.

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Document Conventions

Create a trigger for a Lambda function

Edit triggers for a repository