在地图状态迭代器中使用“ ResultPath”字段时出错？ “步骤功能不支持字段'ResultPath'”

问题描述

每当我在以下代码中使用“ ResultPath”时，我都会不断收到错误消息：“ Step Functions不支持字段'ResultPath'”：

{
  "StartAt": "OuterFunction","States": {
    "OuterFunction": {
      "Type": "Map","Iterator": {
        "StartAt": "GetIteration","States": {
          "GetIteration": {
            "Type": "Pass","ResultPath": "$.iteration","Next": "ReadDynamoDB"
          },"ReadDynamoDB": {
            "Type": "Task","Resource": "arn:aws:states:::dynamodb:getItem","Parameters": {
              "TableName": "TestTable","Key": {
                "Keyword": "$.iteration"
               },"ResultPath": "$.dynamoDBResult"
            },"Next": "DoWork"
          },"DoWork": {
            "Type": "Task","InputPath": "$.dynamoDBResult","Resource": "arn:aws:states:::states:startExecution.sync","Parameters": {
              "StateMachineArn":"arn:aws:states:46372839402:stateMachine:do-work","Input.$": "$.dynamoDBResult"
            },"End": true
          }
        }
      },"End": true
    }
  }
}

对于每次迭代，都打算转到DynamoDB表中，获取与键字符串对应的项目，然后将该项目发送到其他地方以完成更多工作。但是，每当我尝试保存代码时，都会收到一条消息，告诉我不支持“ ResultPath”，并且step函数将不会运行。我非常困惑，因为我看到许多人在线使用“ ResultPath”的例子。这是因为我在迭代器中使用它吗？我还能如何在任务之间传递每次迭代的输入？

解决方法

我认为问题在于您将 ResultPath 包含在 Parameters 中，而它应该在外部。

看这个例子： https://docs.aws.amazon.com/step-functions/latest/dg/connect-ddb.html

    "Read Next Message from DynamoDB": {
      "Type": "Task","Resource": "arn:aws:states:::dynamodb:getItem","Parameters": {
        "TableName": "TransferDataRecords-DDBTable-3I41R5L5EAGT","Key": {
          "MessageId": {"S.$": "$.List[0]"}
        }
      },"ResultPath": "$.DynamoDB","Next": "Send Message to SQS"
    }

这意味着您的代码应该是：

I keep receiving the error,"The field 'ResultPath' is not supported by Step Functions" whenever I use "ResultPath" in the following code:

{
  "StartAt": "OuterFunction","States": {
    "OuterFunction": {
      "Type": "Map","Iterator": {
        "StartAt": "GetIteration","States": {
          "GetIteration": {
            "Type": "Pass","ResultPath": "$.iteration","Next": "ReadDynamoDB"
          },"ReadDynamoDB": {
            "Type": "Task","Parameters": {
              "TableName": "TestTable","Key": {
                "Keyword": "$.iteration"
               }
            },"ResultPath": "$.dynamoDBResult","Next": "DoWork"
          },"DoWork": {
            "Type": "Task","InputPath": "$.dynamoDBResult","Resource": "arn:aws:states:::states:startExecution.sync","Parameters": {
              "StateMachineArn":"arn:aws:states:46372839402:stateMachine:do-work","Input.$": "$.dynamoDBResult"
            },"End": true
          }
        }
      },"End": true
    }
  }
}