AWS Stepfunctions dynamodb States.Runtime 捕获失败答案

【问题标题】：AWS Stepfunctions dynamodb States.Runtime catch failsAWS Stepfunctions dynamodb States.Runtime 捕获失败
【发布时间】：2020-12-27 12:03:04
【问题描述】：

我的 Stepfunction 应该检查发电机中是否存在项目。如果是，则需要生成预签名的 url，否则必须更新 dynamodb 项。

当它与项目匹配时，它会按预期工作，因为当 dynamo getitem 输出为 null 时失败并出现 states.runtime 错误。它不通过 catch 语句。感谢任何帮助。

这是我的代码。

{   "Comment": "A Hello World example of the Amazon States Language using Pass states",   "StartAt": "Hello",   "States": {
    "Hello": {
      "Type": "Pass",
      "Next": "Verify item from DynamoDB"
    },
    "s3_url": {
      "Type": "Pass",
      "Result": "Hello",
      "End": true
    },

    "Verify item from DynamoDB": {
      "Type": "Task",
      "Resource": "arn:aws:states:::dynamodb:getItem",
      "Parameters": {
        "TableName": "s3_table",
        "Key": {
          "etag": {
            "S.$": "$.Records[0].s3.object.eTag"
          }
        }
      },
      "ResultPath": "$.DynamoDB",
      "OutputPath": "$.DynamoDB.Item",
      "Next": "s3_url",
      "Catch": [
        {
          "ErrorEquals": [
            "States.Runtime"
          ],
        
          "Next": "DynamoDB Update"
        }
      ]
    },
    "DynamoDB Update": {
      "Type": "Task",
      "Resource": "arn:aws:states:::dynamodb:putItem",
      "Parameters": {
        "TableName": "s3_table",
        "Item": {
          "etag": {
            "S.$": "$.eTag"
          },
          "filekey": {
            "S": "mp3Files"
          }
        }
      },
      "End": true
    }   } }

【问题讨论】：

标签： amazon-dynamodb aws-step-functions

【解决方案1】：

使用选择状态解决了这个问题。打开以听取有关 Catch 状态的任何建议。

这里是代码。

{
  "Comment": "A Hello World example of the Amazon States Language using Pass states",
  "StartAt": "Hello",
  "States": {
    "Hello": {
      "Type": "Pass",
      "Next": "Verify item from DynamoDB"
    },
    "s3_url": {
      "Type": "Pass",
      "Result": "Hello",
      "End": true
    },
    "Verify item from DynamoDB": {
      "Type": "Task",
      "Resource": "arn:aws:states:::dynamodb:getItem",
      "Parameters": {
       
        "TableName": "s3_table",
        "Key": {
          "etag": {
            "S.$": "$.Records[0].s3.object.eTag"
          }
        }
      },
      "ResultPath": "$.Records[0].DynamoDB",
      "OutputPath": "$",
      "Next": "Choice State",
      "Catch": [
        {
          "ErrorEquals": [
            "States.Runtime"
          ],
          "Next": "DynamoDB Update"
        }
      ]
    },
     "Choice State": {
      "Type": "Choice",
      "Choices": [
        {
          "Variable": "$.Records[0].DynamoDB.Item.etag.S",
          "IsPresent": true,
          "Next": "s3_url"
        }
      ],
      "Default": "DynamoDB Update"
    },
    "DynamoDB Update": {
      "Type": "Task",
      "Resource": "arn:aws:states:::dynamodb:putItem",
      "Parameters": {
        "TableName": "s3_table",
        "Item": {
          "etag": {
            "S.$": "$.Records[0].s3.object.eTag"
          },
          "filekey": {
            "S.$": "$.Records[0].s3.object.key"
          }
        }
      },
      "End": true
    }
  }
}

【讨论】：