in AWS Step Function Console how can I locate the parent state machine that called the current child state machine?

On the child state machine execution detail page, you can find the parent execution ARN in the field Started By:

In the AWS Step Functions console, you can locate the parent state machine that called the current child state machine by using a special parameter called "AWS_STEP_FUNCTIONS_STARTED_BY_EXECUTION_ID". This parameter allows you to associate a started workflow execution with the execution that started it.

When viewing the execution details of a child state machine, you can look for this parameter in the input of the execution. If it's present, it will contain the execution ID of the parent state machine that started this child execution.

To find this information:

1. Open the Step Functions console and navigate to the execution details of your child state machine.
2. Look for the "Input" section in the execution details.
3. Check if the "AWS_STEP_FUNCTIONS_STARTED_BY_EXECUTION_ID" parameter is present in the input.
4. If it's there, the value will be the execution ID of the parent state machine.

Once you have the parent execution ID, you can use it to search for and navigate to the parent state machine execution in the console.

It's important to note that this association is only available if the parent state machine explicitly passed this parameter when starting the child execution. If the parameter wasn't passed, there won't be a direct way to trace back to the parent execution from the child execution details in the console.

For failed executions, you can also check the execution history or error details, which might contain information about the parent execution if it was properly configured.

Remember that implementing this tracing capability requires explicitly passing the execution ID from the parent to the child when starting the execution. If this wasn't done, finding the parent state machine might not be possible through the console alone.
Sources
Start workflow executions from a task state in Step Functions - AWS Step Functions

To locate the parent state machine that called a child state machine in AWS Step Functions:

1. Open the child state machine execution in the AWS Step Functions console.

2. Look for the "Started By" field in the execution details.

3. If started by another state machine, it will show "AWS Step Functions" as the starter.

4. Click on the "Started By" link to view the parent execution ARN.

Alternatively, if X-Ray tracing is enabled, you can use the X-Ray trace to see the complete chain of executions, including the parent state machine.

Best practice: Pass a unique correlation ID and the parent execution ARN from parent to child state machine in the input. This makes tracing relationships between executions easier.