在 Step Functions 中使用 Amazon CloudFormation 创建工作流程 - Amazon Step Functions
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在 Step Functions 中使用 Amazon CloudFormation 创建工作流程

在本教程中,您将使用 Amazon CloudFormation 创建 Amazon Lambda 函数。您将使用 Amazon CloudFormation 控制台和 YAML 模板来创建堆栈(IAM 角色、Lambda 函数和状态机)。然后,您将使用 Step Functions 控制台来启动状态机执行。

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

第 1 步:设置您的 Amazon CloudFormation 模板

在使用示例模板之前,您应该了解如何声明 Amazon CloudFormation 模板的不同部分。

为 Lambda 创建 IAM 角色

定义与 Lambda 函数的 IAM 角色关联的信任策略。以下示例使用 YAML 或 JSON 定义信任策略。

YAML
LambdaExecutionRole: Type: "AWS::IAM::Role" Properties: AssumeRolePolicyDocument: Version: "2012-10-17" Statement: - Effect: Allow Principal: Service: lambda.amazonaws.com Action: "sts:AssumeRole"
JSON
"LambdaExecutionRole": { "Type": "AWS::IAM::Role", "Properties": { "AssumeRolePolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": "lambda.amazonaws.com" }, "Action": "sts:AssumeRole" } ] } }

创建 Lambda 函数

为将打印 Hello World 消息的 Lambda 函数定义以下属性。

重要

确保您的 Lambda 函数与状态机位于相同的 Amazon 账户和 Amazon Web Services 区域下。

YAML
MyLambdaFunction: Type: "AWS::Lambda::Function" Properties: Handler: "index.handler" Role: !GetAtt [ LambdaExecutionRole, Arn ] Code: ZipFile: | exports.handler = (event, context, callback) => { callback(null, "Hello World!"); }; Runtime: "nodejs12.x" Timeout: "25"
JSON
"MyLambdaFunction": { "Type": "AWS::Lambda::Function", "Properties": { "Handler": "index.handler", "Role": { "Fn::GetAtt": [ "LambdaExecutionRole", "Arn" ] }, "Code": { "ZipFile": "exports.handler = (event, context, callback) => {\n callback(null, \"Hello World!\");\n};\n" }, "Runtime": "nodejs12.x", "Timeout": "25" } },

创建用于状态机执行的 IAM 角色

定义与状态机执行的 IAM 角色关联的信任策略。

YAML
StatesExecutionRole: Type: "AWS::IAM::Role" Properties: AssumeRolePolicyDocument: Version: "2012-10-17" Statement: - Effect: "Allow" Principal: Service: - !Sub states.${AWS::Region}.amazonaws.com Action: "sts:AssumeRole" Path: "/" Policies: - PolicyName: StatesExecutionPolicy PolicyDocument: Version: "2012-10-17" Statement: - Effect: Allow Action: - "lambda:InvokeFunction" Resource: "*"
JSON
"StatesExecutionRole": { "Type": "AWS::IAM::Role", "Properties": { "AssumeRolePolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": [ { "Fn::Sub": "states.${AWS::Region}.amazonaws.com" } ] }, "Action": "sts:AssumeRole" } ] }, "Path": "/", "Policies": [ { "PolicyName": "StatesExecutionPolicy", "PolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "lambda:InvokeFunction" ], "Resource": "*" } ] } } ] } },

创建 Lambda 状态机

定义 Lambda 状态机。

YAML
MyStateMachine: Type: "AWS::StepFunctions::StateMachine" Properties: DefinitionString: !Sub - |- { "Comment": "A Hello World example using an Amazon Lambda function", "StartAt": "HelloWorld", "States": { "HelloWorld": { "Type": "Task", "Resource": "${lambdaArn}", "End": true } } } - {lambdaArn: !GetAtt [ MyLambdaFunction, Arn ]} RoleArn: !GetAtt [ StatesExecutionRole, Arn ]
JSON
"MyStateMachine": { "Type": "AWS::StepFunctions::StateMachine", "Properties": { "DefinitionString": { "Fn::Sub": [ "{\n \"Comment\": \"A Hello World example using an Amazon Lambda function\",\n \"StartAt\": \"HelloWorld\",\n \"States\": {\n \"HelloWorld\": {\n \"Type\": \"Task\",\n \"Resource\": \"${lambdaArn}\",\n \"End\": true\n }\n }\n}", { "lambdaArn": { "Fn::GetAtt": [ "MyLambdaFunction", "Arn" ] } } ] }, "RoleArn": { "Fn::GetAtt": [ "StatesExecutionRole", "Arn" ] } } }

第 2 步:使用 Amazon CloudFormation 模板创建 Lambda 状态机

在您了解 Amazon CloudFormation 模板的各个组件后,可以将这些组件放在一起,并使用模板创建 Amazon CloudFormation 堆栈。

创建 Lambda 状态机

  1. 将以下示例数据复制到名为 MyStateMachine.yaml(适用于 YAML 示例)或 MyStateMachine.json(适用于 JSON)的文件中。

    YAML
    AWSTemplateFormatVersion: "2010-09-09" Description: "An example template with an IAM role for a Lambda state machine." Resources: LambdaExecutionRole: Type: "AWS::IAM::Role" Properties: AssumeRolePolicyDocument: Version: "2012-10-17" Statement: - Effect: Allow Principal: Service: lambda.amazonaws.com Action: "sts:AssumeRole" MyLambdaFunction: Type: "AWS::Lambda::Function" Properties: Handler: "index.handler" Role: !GetAtt [ LambdaExecutionRole, Arn ] Code: ZipFile: | exports.handler = (event, context, callback) => { callback(null, "Hello World!"); }; Runtime: "nodejs12.x" Timeout: "25" StatesExecutionRole: Type: "AWS::IAM::Role" Properties: AssumeRolePolicyDocument: Version: "2012-10-17" Statement: - Effect: "Allow" Principal: Service: - !Sub states.${AWS::Region}.amazonaws.com Action: "sts:AssumeRole" Path: "/" Policies: - PolicyName: StatesExecutionPolicy PolicyDocument: Version: "2012-10-17" Statement: - Effect: Allow Action: - "lambda:InvokeFunction" Resource: "*" MyStateMachine: Type: "AWS::StepFunctions::StateMachine" Properties: DefinitionString: !Sub - |- { "Comment": "A Hello World example using an Amazon Lambda function", "StartAt": "HelloWorld", "States": { "HelloWorld": { "Type": "Task", "Resource": "${lambdaArn}", "End": true } } } - {lambdaArn: !GetAtt [ MyLambdaFunction, Arn ]} RoleArn: !GetAtt [ StatesExecutionRole, Arn ]
    JSON
    { "AWSTemplateFormatVersion": "2010-09-09", "Description": "An example template with an IAM role for a Lambda state machine.", "Resources": { "LambdaExecutionRole": { "Type": "AWS::IAM::Role", "Properties": { "AssumeRolePolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": "lambda.amazonaws.com" }, "Action": "sts:AssumeRole" } ] } } }, "MyLambdaFunction": { "Type": "AWS::Lambda::Function", "Properties": { "Handler": "index.handler", "Role": { "Fn::GetAtt": [ "LambdaExecutionRole", "Arn" ] }, "Code": { "ZipFile": "exports.handler = (event, context, callback) => {\n callback(null, \"Hello World!\");\n};\n" }, "Runtime": "nodejs12.x", "Timeout": "25" } }, "StatesExecutionRole": { "Type": "AWS::IAM::Role", "Properties": { "AssumeRolePolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "Service": [ { "Fn::Sub": "states.${AWS::Region}.amazonaws.com" } ] }, "Action": "sts:AssumeRole" } ] }, "Path": "/", "Policies": [ { "PolicyName": "StatesExecutionPolicy", "PolicyDocument": { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "lambda:InvokeFunction" ], "Resource": "*" } ] } } ] } }, "MyStateMachine": { "Type": "AWS::StepFunctions::StateMachine", "Properties": { "DefinitionString": { "Fn::Sub": [ "{\n \"Comment\": \"A Hello World example using an Amazon Lambda function\",\n \"StartAt\": \"HelloWorld\",\n \"States\": {\n \"HelloWorld\": {\n \"Type\": \"Task\",\n \"Resource\": \"${lambdaArn}\",\n \"End\": true\n }\n }\n}", { "lambdaArn": { "Fn::GetAtt": [ "MyLambdaFunction", "Arn" ] } } ] }, "RoleArn": { "Fn::GetAtt": [ "StatesExecutionRole", "Arn" ] } } } } }
  2. 打开 Amazon CloudFormation 控制台并选择创建堆栈

  3. 选择模板页面上,选择将模板上传到 Amazon S3。选择您的 MyStateMachine 文件,然后选择下一步

  4. 指定详细信息页面上,为堆栈名称输入 MyStateMachine,然后选择下一步

  5. 选项页面上,选择下一步

  6. 审核页面上,选择我确认,Amazon CloudFormation 可能创建 IAM 资源。,然后选择创建

    Amazon CloudFormation 开始创建 MyStateMachine 堆栈,并显示 CREATE_IN_PROGRESS 状态。在此过程完成后,Amazon CloudFormation 将显示 CREATE_COMPLETE 状态。

  7. (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:启动状态机执行

在创建您的 Lambda 状态机后,可以开始执行。

启动状态机执行

  1. 打开 Step Functions 控制台,然后选择您使用 Amazon CloudFormation 创建的状态机的名称。

  2. MyStateMachine-ABCDEFGHIJ1K 页面上,选择新执行

    此时将显示新执行页面。

  3. (可选)输入自定义执行名称,以便覆盖生成的默认执行名称。

    非 ASCII 名称和日志记录

    Step Functions 对于状态机、执行、活动和标签接受包含非 ASCII 字符的名称。由于此类字符不适用于 Amazon CloudWatch,因此我们建议您仅使用 ASCII 字符,这样您就可以在 CloudWatch 中跟踪指标。

  4. 选择启动执行

    此时将启动新的状态机执行,并显示一个说明正在运行的执行的新页面。

  5. (可选)在执行详细信息中,查看执行状态以及已开始已关闭时间戳。

  6. 要查看执行结果,请选择输出