sample-github-pull-request.md

GitHub Pull Request and Webhook Filter Sample for CodeBuild

AWS CodeBuild supports webhooks when the source repository is GitHub. This means that for a CodeBuild build project that has its source code stored in a GitHub repository, webhooks enable CodeBuild to rebuild the source code every time a code change is pushed to the repository.

Note
We recommend that you use a filter group to specify which GitHub users can trigger a build in a public repository. This can prevent a user from triggering an unexpected build. For more information, see Filter GitHub Webhook Events.

Create a Build Project with GitHub as the Source Repository and Enable Webhooks (Console)

1. Open the AWS CodeBuild console at https://console.aws.amazon.com/codesuite/codebuild/home.

2. If a CodeBuild information page is displayed, choose Create project. Otherwise, on the navigation pane, expand Build, and then choose Build projects.

3. Choose Create build project.

4. In Project configuration:

   On the Create build project page, in Project configuration, for Project name, enter a name for this build project. Build project names must be unique across each AWS account. You can also include an optional description of the build project to help other users understand what this project is used for.

5. In Source, for Source provider, choose GitHub. Follow the instructions to connect (or reconnect) with GitHub and then choose Authorize.

   Choose Repository in my GitHub account.

   In GitHub repository, enter the URL for your GitHub repository.
   

6. In Primary source webhook events select Rebuild every time a code change is pushed to this repository. You can select this check box only if you chose Repository in my GitHub account.
   

7. In Environment:

   For Environment image, do one of the following:

   • To use a Docker image managed by AWS CodeBuild, choose Managed image, and then make selections from Operating system, Runtime, and Runtime version.
   • To use another Docker image, choose Custom image. For Environment type, choose Linux or Windows. For Custom image type, choose Amazon ECR or Other location. If you choose Other location, enter the name and tag of the Docker image in Docker Hub, using the format docker repository/docker image name. If you choose Amazon ECR, then use Amazon ECR repository and Amazon ECR image to choose the Docker image in your AWS account.
   • To use private Docker image, choose Custom image. For Environment type, choose Linux or Windows. For Custom image type, choose Other location, and then enter the Amazon Resource Name (ARN) of the credentials for your private Docker image. The credentials must be created by AWS Secrets Manager. For more information, see What Is AWS Secrets Manager?

8. In Service role, do one of the following:

   • If you do not have a CodeBuild service role, choose New service role. In Role name, accept the default name or enter your own.
   • If you have a CodeBuild service role, choose Existing service role. In Role name, choose the service role. Note
     When you use the console to create or update a build project, you can create a CodeBuild service role at the same time. By default, the role works with that build project only. If you use the console to associate this service role with another build project, the role is updated to work with the other build project. A service role can work with up to 10 build projects.

9. For Buildspec, do one of the following:

   • Choose Use a buildspec file to use the buildspec.yml file in the source code root directory.
   • Choose Insert build commands to use the console to insert build commands.

   For more information, see the Build Spec Reference.

10. In Artifacts, for Type, do one of the following:

    • If you do not want to create any build output artifacts, choose No artifacts.
    • To store the build output in an Amazon S3 bucket, choose Amazon S3, and then do the following:
      • If you want to use your project name for the build output ZIP file or folder, leave Name blank. Otherwise, enter the name. By default, the artifact name is the project name. If you want to use a different name, enter it in the artifacts name box. If you want to output a ZIP file, include the zip extension.
      • For Bucket name, choose the name of the output bucket.
      • If you chose Insert build commands earlier in this procedure, then for Output files, enter the locations of the files from the build that you want to put into the build output ZIP file or folder. For multiple locations, separate each location with a comma (for example, appspec.yml, target/my-app.jar). For more information, see the description of files in Build Spec Syntax.

11. Expand Additional configuration and set options as appropriate.

12. Choose Create build project. On the Review page, choose Start build to run the build.

Verification Checks

1. Open the AWS CodeBuild console at https://console.aws.amazon.com/codesuite/codebuild/home.

2. In the navigation pane, choose Build projects.

3. Do one of the following:

   • Choose the link for the build project with webhooks you want to verify, and then choose Build details.
   • Choose the button next to the build project with webhooks you want to verify, choose View details, and then choose Build details.

4. In Source, choose the Webhook URL link.

5. In your GitHub repository, on the Settings page, under Webhooks, verify that Pull Requests and Pushes are selected.

6. In your GitHub profile settings, under Personal settings, Applications, Authorized OAuth Apps, you should see that your AWS CodeBuild region has been authorized.
   

Filter GitHub Webhook Events

You can use webhook filter groups to specify which GitHub webhook events trigger a build. For example, you can specify that a build is triggered for specified branches only.

Note
Filter groups work the same way in GitHub and GitHub Enterprise.

You can create one or more webhook filter groups to specify which webhook events trigger a build. A build is triggered if all the filters on one or more filter groups evaluate to true. When you create a filter group, you specify:

• An event. For GitHub, you can choose one or more of the following events: PUSH, PULL_REQUEST_CREATED, PULL_REQUEST_UPDATED, PULL_REQUEST_REOPENED, and PULL_REQUEST_MERGED. The webhook event type is in the X-GitHub-Event header in the webhook payload. In the X-GitHub-Event header, you might see pull_request or push. For a pull request event, the type is in the action field of the webhook event payload. The following table shows how X-GitHub-Event header values and webhook pull request payload action field values map to the available event types.
  [See the AWS documentation website for more details] Note
  The PULL_REQUEST_REOPENED event type can be used with GitHub and GitHub Enterprise only.
• One or more optional filters. Use a regular expression to specify a filter. For an event to trigger a build, every filter associated with it must evaluate to true.
  • ACTOR_ACCOUNT_ID (ACTOR_ID in the console): A webhook event triggers a build when a GitHub or GitHub Enterprise account ID matches the regular expression pattern. This value is found in the id property of the sender object in the webhook payload.
  • HEAD_REF: A webhook event triggers a build when the head reference matches the regular expression pattern (for example, refs/heads/branch-name or refs/tags/tag-name). For a push event, the reference name is found in the ref property in the webhook payload. For pull requests events, the branch name is found in the ref property of the head object in the webhook payload.
  • BASE_REF: A webhook event triggers a build when the base reference matches the regular expression pattern (for example, refs/heads/branch-name). A BASE_REF filter can be used with pull request events only. The branch name is found in the ref property of the base object in the webhook payload.
  • FILE_PATH: A webhook triggers a build when the path of a changed file matches the regular expressions pattern. A FILE_PATH filter can be used with GitHub and GitHub Enterprise push events only.

Note
You can find the webhook payload in the webhook settings of your GitHub repository.

Topics

• Filter GitHub Webhook Events (Console)
• Filter GitHub Webhook Events (SDK)
• Filter GitHub Webhook Events (AWS CloudFormation)

Filter GitHub Webhook Events (Console)

To use the AWS Management Console to filter webhook events:

1. Select Rebuild every time a code change is pushed to this repository when you create your project.

2. From Event type, choose one or more events.

3. To filter when an event triggers a build, under Start a build under these conditions, add one or more optional filters.

4. To filter when an event is not triggered, under Don't start a build under these conditions, add one or more optional filters.

5. Choose Add filter group to add another filter group.

For more information, see Create a Build Project (Console) and WebhookFilter in the AWS CodeBuild API Reference.

In this example, a webhook filter group triggers a build for pull requests only:

Using an example of two webhook filter groups, a build is triggered when one or both evaluate to true:

• The first filter group specifies pull requests that are created, updated, or reopened on branches with Git reference names that match the regular expression ^refs/heads/master$ and head references that match ^refs/heads/branch1$.
• The second filter group specifies push requests on branches with Git reference names that match the regular expression ^refs/heads/branch1$.

In this example, a webhook filter group triggers a build for all requests except tag events.

In this example, a webhook filter group triggers a build only when files with names that match the regular expression ^buildspec.* change.

In this example, a webhook filter group triggers a build only when a change is made by a specified GitHub or GitHub Enterprise user with account ID that matches the regular expression actor-account-id.

Note
For information about how to find your GitHub account ID, see https://api\.github\.com/users/*user\-name*, where user-name is your GitHub user name.

Filter GitHub Webhook Events (SDK)

To use the AWS CodeBuild SDK to filter webhook events, use the filterGroups field in the request syntax of the CreateWebhook or UpdateWebhook API methods. For more information, see WebhookFilter in the CodeBuild API Reference.

To create a webhook filter that triggers a build for pull requests only, insert the following into the request syntax:

"filterGroups": [
   [
        {
            "type": "EVENT", 
            "pattern": "PULL_REQUEST_CREATED, PULL_REQUEST_UPDATED, PULL_REQUEST_REOPENED, PULL_REQUEST_MERGED"
        }
    ]
]

To create a webhook filter that triggers a build for specified branches only, use the pattern parameter to specify a regular expression to filter branch names. Using an example of two filter groups, a build is triggered when one or both evaluate to true:

• The first filter group specifies pull requests that are created, updated, or reopened on branches with Git reference names that match the regular expression ^refs/heads/master$ and head references that match ^refs/heads/myBranch$.
• The second filter group specifies push requests on branches with Git reference names that match the regular expression ^refs/heads/myBranch$.

"filterGroups": [
    [
        {
            "type": "EVENT", 
            "pattern": "PULL_REQUEST_CREATED, PULL_REQUEST_UPDATED, PULL_REQUEST_REOPENED"
        },
        {
            "type": "HEAD_REF", 
            "pattern": "^refs/heads/myBranch$"
        },
        {
            "type": "BASE_REF", 
            "pattern": "^refs/heads/master$"
        }
    ],
    [
        {
            "type": "EVENT", 
            "pattern": "PUSH"
        },
        {
            "type": "HEAD_REF", 
            "pattern": "^refs/heads/myBranch$"
        }
    ]
]

You can use the excludeMatchedPattern parameter to specify which events do not trigger a build. For example, in this example a build is triggered for all requests except tag events.

"filterGroups": [
    [
        {
            "type": "EVENT", 
            "pattern": "PUSH, PULL_REQUEST_CREATED, PULL_REQUEST_UPDATED, PULL_REQUEST_REOPENED, PULL_REQUEST_MERGED"
        },
        {
            "type": "HEAD_REF", 
            "pattern": "^refs/tags/.*", 
            "excludeMatchedPattern": true
        }
    ]
]

You can create a filter that triggers a build only when files with names that match the regular expression in the pattern argument change. In this example, the filter group specifies that a build is triggered only when files with a name that matches the regular expression ^buildspec.* change.

"filterGroups": [
    [
        {
            "type": "EVENT", 
            "pattern": "PUSH"
        },
        {
            "type": "FILE_PATH", 
            "pattern": "^buildspec.*"
        }
    ]
]

You can create a filter that triggers a build only when a change is made by a specified GitHub or GitHub Enterprise user with account ID actor-account-id.

Note
For information about how to find your GitHub account ID, see https://api\.github\.com/users/*user\-name*, where user-name is your GitHub user name.

"filterGroups": [
    [
        {
            "type": "EVENT", 
            "pattern": "PUSH, PULL_REQUEST_CREATED, PULL_REQUEST_UPDATED, PULL_REQUEST_REOPENED, PULL_REQUEST_MERGED"
        },
        {
            "type": "ACTOR_ACCOUNT_ID", 
            "pattern": "actor-account-id"
        }
    ]
]

Filter GitHub Webhook Events (AWS CloudFormation)

To use an AWS CloudFormation template to filter webhook events, use the AWS CodeBuild project's FilterGroups property. The following YAML-formatted portion of a AWS CloudFormation template creates two filter groups. Together, they trigger a build when one or both evaluate to true:

• The first filter group specifies pull requests are created or updated on branches with Git reference names that match the regular expression ^refs/heads/master$ by a GitHub user that does not have account ID 12345.
• The second filter group specifies push requests are created on files with names that match the regular expression READ_ME in branches with Git reference names that match the regular expression ^refs/heads/.*.

CodeBuildProject:
  Type: AWS::CodeBuild::Project
  Properties:
    Name: MyProject
    ServiceRole: service-role
    Artifacts:
      Type: NO_ARTIFACTS
    Environment:
      Type: LINUX_CONTAINER
      ComputeType: BUILD_GENERAL1_SMALL
      Image: aws/codebuild/standard:2.0
    Source:
      Type: GITHUB
      Location: source-location
    Triggers:
      Webhook: true
      FilterGroups:
        - - Type: EVENT
            Pattern: PULL_REQUEST_CREATED,PULL_REQUEST_UPDATED
          - Type: BASE_REF
            Pattern: ^refs/heads/master$
            ExcludeMatchedPattern: false
          - Type: ACTOR_ACCOUNT_ID
            Pattern: 12345
            ExcludeMatchedPattern: true
        - - Type: EVENT
            Pattern: PUSH
          - Type: HEAD_REF
            Pattern: ^refs/heads/.*
          - Type: FILE_PATH
            Pattern: READ_ME
            ExcludeMatchedPattern: true