第 1 步：创建一个模板第 2 步：创建一个堆栈第 3 步：批准 SNS 订阅第 4 步：运行状态机模板源代码

部署示例人员批准项目

本教程介绍如何部署允许 Amazon Step Functions 执行在任务期间暂停并等待用户对电子邮件做出响应的人员批准项目。一旦用户批准任务继续，工作流程就会进入下一个状态。

部署本教程中包含的 Amazon CloudFormation 堆栈将创建所有必要的资源，包括：

Amazon API Gateway 资源
一个 Amazon Lambda 函数
一台 Amazon Step Functions 状态机
Amazon Simple Notification Service 电子邮件主题
相关 Amazon Identity and Access Management 角色和权限

注意

在创建 Amazon CloudFormation 堆栈时，您需要提供一个可以访问的有效电子邮件地址。

有关更多信息，请参阅《Amazon CloudFormation 用户指南》中的使用 CloudFormation 模板和AWS::StepFunctions::StateMachine资源。

步骤 1：创建 Amazon CloudFormation 模板

从 Amazon CloudFormation 模板源代码部分复制示例代码。
将 Amazon CloudFormation 模板的源文件粘贴到本地计算机上的文件中。

在此示例中，文件名为 human-approval.yaml。

第 2 步：创建一个堆栈

登录 Amazon CloudFormation 控制台。
选择创建堆栈，然后选择使用新资源（标准）。
在创建堆栈页面上，执行以下操作：
1. 在先决条件 - 准备模板部分，确保选中模板已就绪。
2. 在指定模板部分，选择上传模板文件，然后选择选择文件，上传您之前创建的包含模板源代码的 human-approval.yaml 文件。
选择下一步。
在指定堆栈详细信息页面中，请执行以下操作：
1. 在堆栈名称中，输入堆栈的名称。
2. 在参数下，输入一个有效的电子邮件地址。您将使用此电子邮件地址订阅 Amazon SNS 主题。
选择下一步，然后再次选择下一步。
在查看页面上，选择我确认 Amazon CloudFormation 可能会创建 IAM 资源，然后选择创建。

Amazon CloudFormation 开始创建您的堆栈并显示 CREATE_IN_ PROGRESS 状态。该过程完成后， Amazon CloudFormation 将显示 “创建_完成” 状态。
（可选）要显示您的堆栈中的资源，请选择堆栈，然后选择资源选项卡。

第 3 步：批准 Amazon SNS 订阅

创建 Amazon SNS 主题后，您将收到一封电子邮件，要求您确认订阅。

打开您在创建 Amazon CloudFormation 堆栈时提供的电子邮件帐户。
打开来自 no-reply@sns.amazonaws.com 的 Amazon 通知 – 订阅确认电子邮件。

该电子邮件将列出 Amazon SNS 主题的 Amazon 资源名称，以及确认链接。
选择确认订阅链接。

第 4 步：运行状态机

在HumanApprovalLambdaStateMachine页面上，选择 “开始执行”。

随即显示启动执行对话框。
在启动执行对话框中，执行以下操作：
1. （可选）要识别您的执行，您可以在名称框中为其指定一个名称。默认情况下，Step Functions 会自动生成一个唯一的执行名称。
  
  注意
  Step Functions 允许您为状态机、执行、活动、速率控制和包含非 ASCII 字符的标签创建名称。这些非 ASCII 名称不适用于亚马逊。 CloudWatch为确保您可以跟踪 CloudWatch 指标，请选择仅使用 ASCII 字符的名称。
2. 在输入框中，输入以下 JSON 输入，运行您的工作流。
```
{
    "Comment": "Testing the human approval tutorial."
}
```
3. 选择启动执行。
  
  ApprovalTest状态机开始执行，并在 Lambda 回调任务处暂停。
4. Step Functions 控制台会将您引导到一个以您的执行 ID 为标题的页面。该页面被称为执行详细信息页面。在此页面上，您可以随着执行的进展或者在执行完成后查看执行结果。
  
  要查看执行结果，请在图表视图上选择各个状态，然后在步骤详细信息窗格中选择各个选项卡，分别查看每个状态的详细信息，包括输入、输出和定义。有关可在执行详细信息页面上查看的执行信息的详细信息，请参阅“执行详细信息”页面 – 界面概述。
在您之前用于 Amazon SNS 主题的电子邮件账户中，打开主题为 “需要审批” 的邮件。 Amazon Step Functions

此消息包括用于批准和拒绝的独立 URL。
选择批准 URL。

工作流程根据您的选择继续。

Amazon CloudFormation 模板源代码

使用此 Amazon CloudFormation 模板来部署人工批准流程工作流的示例。


AWSTemplateFormatVersion: "2010-09-09"
Description: "AWS Step Functions Human based task example. It sends an email with an HTTP URL for approval."
Parameters:
  Email:
    Type: String
    AllowedPattern: "^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\\.[a-zA-Z0-9-.]+$"
    ConstraintDescription: Must be a valid email address.
Resources:
  # Begin API Gateway Resources
  ExecutionApi:
    Type: "AWS::ApiGateway::RestApi"
    Properties:
      Name: "Human approval endpoint"
      Description: "HTTP Endpoint backed by API Gateway and Lambda"
      FailOnWarnings: true

  ExecutionResource:
    Type: 'AWS::ApiGateway::Resource'
    Properties:
      RestApiId: !Ref ExecutionApi
      ParentId: !GetAtt "ExecutionApi.RootResourceId"
      PathPart: execution

  ExecutionMethod:
    Type: "AWS::ApiGateway::Method"
    Properties:
      AuthorizationType: NONE
      HttpMethod: GET
      Integration:
        Type: AWS
        IntegrationHttpMethod: POST
        Uri: !Sub "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${LambdaApprovalFunction.Arn}/invocations"
        IntegrationResponses:
          - StatusCode: 302
            ResponseParameters:
              method.response.header.Location: "integration.response.body.headers.Location"
        RequestTemplates:
          application/json: |
            {
              "body" : $input.json('$'),
              "headers": {
                #foreach($header in $input.params().header.keySet())
                "$header": "$util.escapeJavaScript($input.params().header.get($header))" #if($foreach.hasNext),#end

                #end
              },
              "method": "$context.httpMethod",
              "params": {
                #foreach($param in $input.params().path.keySet())
                "$param": "$util.escapeJavaScript($input.params().path.get($param))" #if($foreach.hasNext),#end

                #end
              },
              "query": {
                #foreach($queryParam in $input.params().querystring.keySet())
                "$queryParam": "$util.escapeJavaScript($input.params().querystring.get($queryParam))" #if($foreach.hasNext),#end

                #end
              }  
            }
      ResourceId: !Ref ExecutionResource
      RestApiId: !Ref ExecutionApi
      MethodResponses:
        - StatusCode: 302
          ResponseParameters:
            method.response.header.Location: true

  ApiGatewayAccount:
    Type: 'AWS::ApiGateway::Account'
    Properties:
      CloudWatchRoleArn: !GetAtt "ApiGatewayCloudWatchLogsRole.Arn"
  
  ApiGatewayCloudWatchLogsRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - apigateway.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Policies:
        - PolicyName: ApiGatewayLogsPolicy
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - "logs:*"
                Resource: !Sub "arn:${AWS::Partition}:logs:*:*:*"

  ExecutionApiStage:
    DependsOn:
      - ApiGatewayAccount
    Type: 'AWS::ApiGateway::Stage'
    Properties:
      DeploymentId: !Ref ApiDeployment
      MethodSettings:
        - DataTraceEnabled: true
          HttpMethod: '*'
          LoggingLevel: INFO
          ResourcePath: /*
      RestApiId: !Ref ExecutionApi
      StageName: states

  ApiDeployment:
    Type: "AWS::ApiGateway::Deployment"
    DependsOn:
      - ExecutionMethod
    Properties:
      RestApiId: !Ref ExecutionApi
      StageName: DummyStage
  # End API Gateway Resources

  # Begin
  # Lambda that will be invoked by API Gateway
  LambdaApprovalFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      Code:
        ZipFile:
          Fn::Sub: |
            const { SFN: StepFunctions } = require("@aws-sdk/client-sfn");
            var redirectToStepFunctions = function(lambdaArn, statemachineName, executionName, callback) {
              const lambdaArnTokens = lambdaArn.split(":");
              const partition = lambdaArnTokens[1];
              const region = lambdaArnTokens[3];
              const accountId = lambdaArnTokens[4];

              console.log("partition=" + partition);
              console.log("region=" + region);
              console.log("accountId=" + accountId);

              const executionArn = "arn:" + partition + ":states:" + region + ":" + accountId + ":execution:" + statemachineName + ":" + executionName;
              console.log("executionArn=" + executionArn);

              const url = "https://console.aws.amazon.com/states/home?region=" + region + "#/executions/details/" + executionArn;
              callback(null, {
                  statusCode: 302,
                  headers: {
                    Location: url
                  }
              });
            };

            exports.handler = (event, context, callback) => {
              console.log('Event= ' + JSON.stringify(event));
              const action = event.query.action;
              const taskToken = event.query.taskToken;
              const statemachineName = event.query.sm;
              const executionName = event.query.ex;

              const stepfunctions = new StepFunctions();

              var message = "";

              if (action === "approve") {
                message = { "Status": "Approved! Task approved by ${Email}" };
              } else if (action === "reject") {
                message = { "Status": "Rejected! Task rejected by ${Email}" };
              } else {
                console.error("Unrecognized action. Expected: approve, reject.");
                callback({"Status": "Failed to process the request. Unrecognized Action."});
              }

              stepfunctions.sendTaskSuccess({
                output: JSON.stringify(message),
                taskToken: event.query.taskToken
              })
              .then(function(data) {
                redirectToStepFunctions(context.invokedFunctionArn, statemachineName, executionName, callback);
              }).catch(function(err) {
                console.error(err, err.stack);
                callback(err);
              });
            }
      Description: Lambda function that callback to AWS Step Functions
      FunctionName: LambdaApprovalFunction
      Handler: index.handler
      Role: !GetAtt "LambdaApiGatewayIAMRole.Arn"
      Runtime: nodejs18.x

  LambdaApiGatewayInvoke:
    Type: "AWS::Lambda::Permission"
    Properties:
      Action: "lambda:InvokeFunction"
      FunctionName: !GetAtt "LambdaApprovalFunction.Arn"
      Principal: "apigateway.amazonaws.com"
      SourceArn: !Sub "arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${ExecutionApi}/*"

  LambdaApiGatewayIAMRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Action:
              - "sts:AssumeRole"
            Effect: "Allow"
            Principal:
              Service:
                - "lambda.amazonaws.com"
      Policies:
        - PolicyName: CloudWatchLogsPolicy
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - "logs:*"
                Resource: !Sub "arn:${AWS::Partition}:logs:*:*:*"
        - PolicyName: StepFunctionsPolicy
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - "states:SendTaskFailure"
                  - "states:SendTaskSuccess"
                Resource: "*"
  # End Lambda that will be invoked by API Gateway

  # Begin state machine that publishes to Lambda and sends an email with the link for approval
  HumanApprovalLambdaStateMachine:
    Type: AWS::StepFunctions::StateMachine
    Properties:
      RoleArn: !GetAtt LambdaStateMachineExecutionRole.Arn
      DefinitionString:
        Fn::Sub: |
          {
              "StartAt": "Lambda Callback",
              "TimeoutSeconds": 3600,
              "States": {
                  "Lambda Callback": {
                      "Type": "Task",
                      "Resource": "arn:${AWS::Partition}:states:::lambda:invoke.waitForTaskToken",
                      "Parameters": {
                        "FunctionName": "${LambdaHumanApprovalSendEmailFunction.Arn}",
                        "Payload": {
                          "ExecutionContext.$": "$$",
                          "APIGatewayEndpoint": "https://${ExecutionApi}.execute-api.${AWS::Region}.amazonaws.com/states"
                        }
                      },
                      "Next": "ManualApprovalChoiceState"
                  },
                  "ManualApprovalChoiceState": {
                    "Type": "Choice",
                    "Choices": [
                      {
                        "Variable": "$.Status",
                        "StringEquals": "Approved! Task approved by ${Email}",
                        "Next": "ApprovedPassState"
                      },
                      {
                        "Variable": "$.Status",
                        "StringEquals": "Rejected! Task rejected by ${Email}",
                        "Next": "RejectedPassState"
                      }
                    ]
                  },
                  "ApprovedPassState": {
                    "Type": "Pass",
                    "End": true
                  },
                  "RejectedPassState": {
                    "Type": "Pass",
                    "End": true
                  }
              }
          }

  SNSHumanApprovalEmailTopic:
    Type: AWS::SNS::Topic
    Properties:
      Subscription:
        -
           Endpoint: !Sub ${Email}
           Protocol: email
  
  LambdaHumanApprovalSendEmailFunction:
    Type: "AWS::Lambda::Function"
    Properties:
      Handler: "index.lambda_handler"
      Role: !GetAtt LambdaSendEmailExecutionRole.Arn
      Runtime: "nodejs18.x"
      Timeout: "25"
      Code:
        ZipFile:
          Fn::Sub: |
            console.log('Loading function');
            const { SNS } = require("@aws-sdk/client-sns");
            exports.lambda_handler = (event, context, callback) => {
                console.log('event= ' + JSON.stringify(event));
                console.log('context= ' + JSON.stringify(context));

                const executionContext = event.ExecutionContext;
                console.log('executionContext= ' + executionContext);

                const executionName = executionContext.Execution.Name;
                console.log('executionName= ' + executionName);

                const statemachineName = executionContext.StateMachine.Name;
                console.log('statemachineName= ' + statemachineName);

                const taskToken = executionContext.Task.Token;
                console.log('taskToken= ' + taskToken);

                const apigwEndpint = event.APIGatewayEndpoint;
                console.log('apigwEndpint = ' + apigwEndpint)

                const approveEndpoint = apigwEndpint + "/execution?action=approve&ex=" + executionName + "&sm=" + statemachineName + "&taskToken=" + encodeURIComponent(taskToken);
                console.log('approveEndpoint= ' + approveEndpoint);

                const rejectEndpoint = apigwEndpint + "/execution?action=reject&ex=" + executionName + "&sm=" + statemachineName + "&taskToken=" + encodeURIComponent(taskToken);
                console.log('rejectEndpoint= ' + rejectEndpoint);

                const emailSnsTopic = "${SNSHumanApprovalEmailTopic}";
                console.log('emailSnsTopic= ' + emailSnsTopic);

                var emailMessage = 'Welcome! \n\n';
                emailMessage += 'This is an email requiring an approval for a step functions execution. \n\n'
                emailMessage += 'Please check the following information and click "Approve" link if you want to approve. \n\n'
                emailMessage += 'Execution Name -> ' + executionName + '\n\n'
                emailMessage += 'Approve ' + approveEndpoint + '\n\n'
                emailMessage += 'Reject ' + rejectEndpoint + '\n\n'
                emailMessage += 'Thanks for using Step functions!'
                
                const sns = new SNS();
                var params = {
                  Message: emailMessage,
                  Subject: "Required approval from AWS Step Functions",
                  TopicArn: emailSnsTopic
                };

                sns.publish(params)
                  .then(function(data) {
                    console.log("MessageID is " + data.MessageId);
                    callback(null);
                  }).catch(
                    function(err) {
                    console.error(err, err.stack);
                    callback(err);
                  });
            }

  LambdaStateMachineExecutionRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: Allow
            Principal:
              Service: states.amazonaws.com
            Action: "sts:AssumeRole"
      Policies:
        - PolicyName: InvokeCallbackLambda
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - "lambda:InvokeFunction"
                Resource:
                  - !Sub "${LambdaHumanApprovalSendEmailFunction.Arn}"

  LambdaSendEmailExecutionRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: "sts:AssumeRole"
      Policies:
        - PolicyName: CloudWatchLogsPolicy
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - "logs:CreateLogGroup"
                  - "logs:CreateLogStream"
                  - "logs:PutLogEvents"
                Resource: !Sub "arn:${AWS::Partition}:logs:*:*:*"
        - PolicyName: SNSSendEmailPolicy
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - "SNS:Publish"
                Resource:
                  - !Sub "${SNSHumanApprovalEmailTopic}"

# End state machine that publishes to Lambda and sends an email with the link for approval
Outputs:
  ApiGatewayInvokeURL:
    Value: !Sub "https://${ExecutionApi}.execute-api.${AWS::Region}.amazonaws.com/states"
  StateMachineHumanApprovalArn:
    Value: !Ref HumanApprovalLambdaStateMachine

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使用 Lambda 函数

在 Step Functions 中查看 X-Ray 跟踪