Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Troubleshooting service integrations

My job is complete in the downstream service, but in Step Functions the task state remains "In progress" or its completion is delayed.

For .sync service integration patterns, Step Functions uses EventBridge rules, downstream APIs, or a combination of both to detect the downstream job status. For some services, Step Functions does not create EventBridge rules to monitor. For example, for the Amazon Glue service integration, instead of using EventBridge rules, Step Functions makes a glue:GetJobRun call. Because of the frequency of API calls, there is a difference between the downstream task completion and the Step Functions task completion time. Step Functions requires IAM permissions to manage the EventBridge rules and to make calls to the downstream service. For more details about how insufficient permissions on your execution role can affect the completion of tasks, see Additional permissions for tasks using the Run a Job pattern.

I want to return a JSON output from a nested state machine execution.

There are two Step Functions synchronous service integrations for Step Functions: startExecution.sync and startExecution.sync:2. Both wait for the nested state machine to complete, but they return different Output formats. You can use startExecution.sync:2 to return a JSON output under Output.

I can't invoke a Lambda function from another account.

Accessing the Lambda function with cross-account support

If cross-account access of Amazon resources is available in your Region, use the following method to invoke a Lambda function from another account.

To invoke a cross-account resource in your workflows, do the following:

For an example, see Tutorial: Accessing cross-account Amazon resources.

For an example of a Task state definition that specifies a cross-account resource, see .

Accessing the Lambda function without cross-account support

If cross-account access of Amazon resources is unavailable in your Region, use the following method to invoke a Lambda function from another account.

In the Task state’s Resource field, use arn:aws:states:::lambda:invoke and pass the FunctionArn in parameters. The IAM role that is associated with the state machine must have the right permissions to invoke cross-account Lambda functions: lambda:invokeFunction.

{  
   "StartAt":"CallLambda",
   "States":{  
      "CallLambda":{  
         "Type":"Task",
         "Resource":"arn:aws:states:::lambda:invoke",
         "Parameters":{  
            "FunctionName":"arn:aws:lambda:us-west-2:123456789012:function:my-function"
         },
         "End":true
      }
   }
}

I'm unable to see task tokens passed from .waitForTaskToken states.

In the Task state’s Parameters field, you must pass a task token. For example, you could use something similar to the following code.

{  
   "StartAt":"taskToken",
   "States":{  
      "taskToken":{  
         "Type":"Task",
         "Resource":"arn:aws:states:::lambda:invoke.waitForTaskToken",
         "Parameters":{  
            "FunctionName":"get-model-review-decision",
            "Payload":{  
               "token.$":"$$.Task.Token"
            },
         },
         "End":true
      }
   }
}