AWS Step Functions：如何使用 Pass 步骤 "rename" 输入参数

Question

我有一个状态机，其中包含以下相关状态：

States:
  'Analyze Report':
    Type: Task
    Resource: 'arn:aws:states:::lambda:invoke'
    Parameters:
      FunctionName: '(redacted)'
    OutputPath: '$.Payload'
    Next: 'Setup Email'
  'Setup Email':
    Type: Pass
    Result:
      recipients: '$.accounts'
      subject: 'some email subject'
      body: 'some email body'
    ResultPath: '$'
    Next: 'Send Email'
  'Send Email':
    Type: Task
    Resource: 'arn:aws:states:::lambda:invoke'
    Parameters:
      FunctionName: '(redacted)'
    OutputPath: '$.Payload'
    Next: '(some downstream task)'

与 Analyze Report 步骤关联的 lambda 函数的输出格式为：

{
  "accounts": ["foo", "bar", "baz"],
  "error_message": null,
  "success": true
}

与 Send Email 步骤关联的 lambda 函数需要以下形式的输入：

{
  "recipients": ["foo", "bar", "baz"],
  "subject": "some email subject",
  "body": "some email body"
}

查看状态函数的测试执行时，似乎 Setup Email 步骤未成功将 $.accounts 字符串插入 accounts 数组输出 Analyze Report 步骤。相反，Send Email 步骤会看到以下输入：

{
  "recipients": "$.accounts",
  "subject": "some email subject",
  "body": "some email body"
}

我尝试了各种组合，例如设置：

# (within the `Setup Email` step)
Result:
  'recipients.$': '$.accounts'

但它似乎不想插值。 AWS提供的文档在这方面似乎有点欠缺

TL;DR: 如何使用 Pass 类型的阶跃函数步骤有效地“重命名”输入参数（使用数组值）？

Answer 1

您需要在 Pass 状态下使用 Parameters。这是一个例子：

{
  "Comment": "A Hello World example of the Amazon States Language using Pass states",
  "StartAt": "Hello",
  "States": {
    "Hello": {
      "Type": "Pass",
      "Parameters": {
        "newName.$": "$.oldName"
      },
      "Next": "World"
    },
    "World": {
      "Type": "Pass",
      "Result": "World",
      "End": true
    }
  }
}

当我运行上面的负载为{ "oldName": "some value" }时，第二个状态的输入是{ "newName": "some value" }。

AWS Step Functions：如何使用 Pass 步骤 "rename" 输入参数

AWS Step Functions : How to "rename" an input parameter using a Pass step

aws-lambda

aws-step-functions