Amazon CodeCatalyst is no longer open to new customers. Existing customers can continue to use the service as normal. For more information, see [How to migrate from CodeCatalyst](migration.md).

# Examples of referencing predefined variables
<a name="workflows-predefined-examples"></a>

The following examples show how to reference predefined variables in the workflow definition file.

For more information about predefined variables, see [Using predefined variables](workflows-using-predefined-variables.md).

**Topics**
+ [Example: Referencing the "CommitId" predefined variable](#workflows-working-with-variables-ex-refer-action)
+ [Example: Referencing the "BranchName" predefined variable](#workflows-working-with-variables-ex-branch)

## Example: Referencing the "CommitId" predefined variable
<a name="workflows-working-with-variables-ex-refer-action"></a>

The following example shows you how to refer to the `CommitId` predefined variable in the `MyBuildAction` action. The `CommitId` variable is output automatically by CodeCatalyst. For more information, see [List of predefined variables](workflow-ref-action-variables.md).

Although the example shows the variable being used in the build action, you can use `CommitId` in any action.

```
MyBuildAction:
    Identifier: aws/build@v1
    Inputs:
      Sources:
        - WorkflowSource
    Configuration:
      Steps:
      #Build Docker image and tag it with a commit ID
        - Run: docker build -t image-repo/my-docker-image:latest .
        - Run: docker tag image-repo/my-docker-image:${WorkflowSource.CommitId}
```

## Example: Referencing the "BranchName" predefined variable
<a name="workflows-working-with-variables-ex-branch"></a>

The following example shows you how to refer to the `BranchName` predefined variable in the `CDKDeploy` action. The `BranchName` variable is output automatically by CodeCatalyst. For more information, see [List of predefined variables](workflow-ref-action-variables.md).

Although the example shows the variable being used in the **AWS CDK deploy** action, you can use `BranchName` in any action.

```
CDKDeploy:
    Identifier: aws/cdk-deploy@v2
    Inputs:
      Sources:
        - WorkflowSource
    Configuration:
      StackName: app-stack-${WorkflowSource.BranchName}
```