使用AWS Lambda和Step Functions实现有状态的工作流，可以根据不同的事件和条件决定程序的流程。

代码示例：

1.创建Lambda函数

exports.handler = async (event) => {
  console.log('Received input: ', JSON.stringify(event));
  const response = {
    statusCode: 200,
    body: JSON.stringify('Hello from Lambda!'),
  };
  return response;
};

2.创建Step Functions状态机

{
  "Comment": "A sample Amazon Step Functions state machine that integrates with Lambda.",
  "StartAt": "Invoke Lambda function",
  "States": {
    "Invoke Lambda function": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:REGION:ACCOUNT_ID:function:LAMBDA_FUNCTION_NAME",
      "InputPath": "$.input",
      "OutputPath": "$.result",
      "ResultPath": "$.output",
      "Next": "Process result"
    },
    "Process result": {
      "Type": "Pass",
      "Result": "Completed",
      "End": true
    }
  }
}

3.集成Lambda和Step Functions

添加Lambda函数到状态机中：

const stateMachineArn = 'arn:aws:states:REGION:ACCOUNT_ID:stateMachine:STATE_MACHINE_NAME';
const lambdaArn = 'arn:aws:lambda:REGION:ACCOUNT_ID:function:LAMBDA_FUNCTION_NAME';

const addLambdaToStateMachine = async () => {
  const stateMachineParams = {
    stateMachineArn,
    definition: JSON.stringify(stateMachineDefinition),
  };
  const stateMachineResponse = await stepfunctions.createStateMachine(stateMachineParams).promise();
  console.log('Created state machine: ', stateMachineResponse);

  const lambdaParams = {
    action: 'lambda:invokeFunction',
    functionArn: lambdaArn,
    stateMachineArn,
    principal: 'states.amazonaws.com',
  };
  const lambdaResponse = await lambda.addPermission(lambdaParams).promise();
  console.log('Added Lambda permission: ', lambdaResponse);
};

触发状态机：

const input = {
  key1: 'value1',
  key2: 'value2',
};

const triggerStateMachine = async () => {
  const stepFunctionParams = {