# Start Step Function execution within Step Function with CDK

This pattern demonstrates how to create two State Machines with one as a step in the other State Machine. Also, callback pattern is used to hold the parent execution until child execution is completed. Implemented with CDK (TypeScript).

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/sfn-to-sfn-cdk

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the [AWS Pricing page](https://aws.amazon.com/pricing/) for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

## Requirements

* [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
* [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured
* [Git Installed](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git)
* [Node and NPM](https://nodejs.org/en/download/) installed
* [AWS Cloud Development Kit](https://docs.aws.amazon.com/cdk/latest/guide/cli.html) (AWS CDK) installed

## Deployment Instructions

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:
    ``` 
    git clone https://github.com/aws-samples/serverless-patterns
    ```
1. Change directory to the pattern directory:
    ```
    cd sfn-to-sfn-cdk
    ```
2. Run below command to install required dependancies:
    ```
    npm install
    ```
4. From the command line, run:
    ```
    cdk deploy --all
    ```

## Testing

1. In the stack output, you can see `parentStateMachine` and `childStateMachine`.

2. Start a new execution with empty input.

3. You can see there is a new execution started in `childStateMachine`.

4. Also, you can see, the execution in `parentStateMachine` will only become `Succeeded` when the execution in `childStateMachine` completed.

## Cleanup
 
1. To delete the stack, run:
    ```bash
    cdk destroy --all
    ```
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