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本教程向您展示如何使用 AWS CloudFormation 创建基本 AWS Lambda 函数。您将使用 AWS 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 AWS Step Functions 控制台启动状态机执行。
有关更多信息，请参阅 AWS CloudFormation 用户指南 中的使用 CloudFormation 模板和 AWS::StepFunctions::StateMachine 资源。
步骤 1：设置您的 AWS CloudFormation 模板
在使用示例模板之前，您应该了解如何声明 AWS CloudFormation 模板的不同部分。
创建用于 Lambda 的 IAM 角色
定义与 Lambda 函数的 IAM 角色关联的信任策略。
- 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
定义输出消息 Hello World 的 Lambda 函数的以下属性。
确保您的 Lambda 函数与状态机位于同一 AWS 账户和 AWS 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 AWS Lambda function",
"StartAt": "HelloWorld",
"States": {
"HelloWorld": {
"Type": "Task",
"Resource": "${lambdaArn}",
"End": true
}
}
}
- {lambdaArn: !GetAtt [ MyLambdaFunction, Arn ]}
RoleArn: !GetAtt [ StatesExecutionRole, Arn ]
- JSON
-
"MyStateMachine": {
"Type": "AWS::StepFunctions::StateMachine",
"Properties": {
"DefinitionString": {
"Fn::Sub": [
"{\n \"Comment\": \"A Hello World example using an AWS Lambda function\",\n \"StartAt\": \"HelloWorld\",\n \"States\": {\n \"HelloWorld\": {\n \"Type\": \"Task\",\n \"Resource\": \"${lambdaArn}\",\n \"End\": true\n }\n }\n}",
{
"lambdaArn": {
"Fn::GetAtt": [
"MyLambdaFunction",
"Arn"
]
}
}
]
},
"RoleArn": {
"Fn::GetAtt": [
"StatesExecutionRole",
"Arn"
]
}
}
}
步骤 2：使用 AWS CloudFormation 模板创建 Lambda 状态机
在您了解 AWS CloudFormation 模板的各个部分后，可以将这些部分放在一起，并使用模板创建 AWS CloudFormation 堆栈。
创建 Lambda 状态机
-
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.${AWS::Region}.amazonaws.com
Action: "sts:AssumeRole"
Path: "/"
Policies:
- PolicyName: StatesExecutionPolicy
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- "lambda:InvokeFunction"
Resource: "*"
MyStateMachine:
Type: "AWS::StepFunctions::StateMachine"
Properties:
DefinitionString:
!Sub
- |-
{
"Comment": "A Hello World example using an AWS Lambda function",
"StartAt": "HelloWorld",
"States": {
"HelloWorld": {
"Type": "Task",
"Resource": "${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.${AWS::Region}.amazonaws.com"
}
]
},
"Action": "sts:AssumeRole"
}
]
},
"Path": "/",
"Policies": [
{
"PolicyName": "StatesExecutionPolicy",
"PolicyDocument": {
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"lambda:InvokeFunction"
],
"Resource": "*"
}
]
}
}
]
}
},
"MyStateMachine": {
"Type": "AWS::StepFunctions::StateMachine",
"Properties": {
"DefinitionString": {
"Fn::Sub": [
"{\n \"Comment\": \"A Hello World example using an AWS Lambda function\",\n \"StartAt\": \"HelloWorld\",\n \"States\": {\n \"HelloWorld\": {\n \"Type\": \"Task\",\n \"Resource\": \"${lambdaArn}\",\n \"End\": true\n }\n }\n}",
{
"lambdaArn": {
"Fn::GetAtt": [
"MyLambdaFunction",
"Arn"
]
}
}
]
},
"RoleArn": {
"Fn::GetAtt": [
"StatesExecutionRole",
"Arn"
]
}
}
}
}
}
-
打开 AWS CloudFormation 控制台并选择创建堆栈。
-
在 Select Template (选择模板) 页面上，选择 Upload a template to Amazon S3 (将模板上传到 Amazon S3)。选择您的 MyStateMachine 文件，然后选择 Next。
-
在指定详细信息页面上，为堆栈名称输入 MyStateMachine，然后选择下一步。
-
在 Options 页面上，选择 Next。
-
在审核页面上，选择我确认，AWS CloudFormation 可能创建 IAM 资源。，然后选择创建。
AWS CloudFormation 开始创建 MyStateMachine 堆栈，并显示 CREATE_IN_PROGRESS 状态。在此过程完成后，AWS CloudFormation 将显示 CREATE_COMPLETE 状态。
-
(可选) 要显示您的堆栈中的资源，请选择堆栈，然后选择 Resources 选项卡。
步骤 3：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
-
打开 Step Functions 控制台，然后选择您使用 AWS CloudFormation 创建的状态机的名称。
-
在 MyStateMachine-ABCDEFGHIJ1K 页面上，选择 New execution。
此时将显示 New execution 页面。
-
（可选）为帮助您标识执行，您可以在 Enter an execution name (输入执行名称) 框中为执行指定一个 ID。如果未输入 ID，Step Functions 将自动生成一个唯一 ID。
Step Functions 允许您创建包含非 ASCII 字符的状态机、执行和活动名称。这些非 ASCII 名称不适用于 Amazon CloudWatch。为确保您可以跟踪
CloudWatch 指标，请选择一个只使用 ASCII 字符的名称。
-
选择 Start Execution (开始执行)。
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。
-
（可选）在 Execution Details (执行详细信息) 中，查看 Execution Status (执行状态) 以及 Started (已开始) 和 Closed (已关闭) 时间戳。
-
要查看执行结果，请选择 Output。
