node.js - AWS lambda 实例在 xstate 调用承诺时关闭

Question

我有一个 lambda 函数，它使用 xstate 顺序执行某些任务，其中一个步骤是将数据保存到 dynamo db。但是，只要执行以下行，我的 lambda 就会结束执行。

const response = await new DynamoDB.DocumentClient().put(params).promise();

我的代码：

import {Handler} from "aws-lambda";
import {interpret} from 'xstate';
import { Machine} from "xstate";
import {PutItemInput} from "aws-sdk/clients/dynamodb";
import {DynamoDB} from "aws-sdk";

export const recordProcessor: Handler = async (event) => {
  console.log('records size----->', event.Records.length);
  for (const record of event.Records) {
      const body = JSON.parse(record.body);
      console.log('body ----->', body);

    interpret(Machine({id:'test',
      context:body,
      initial: 'start',
      states:{
        start: {
          invoke: {
            src: context => initiate(context),
            onDone: {
              target: 'success'
            }
          }
        },
        success: {
          type: 'final'
        }
      }
    })).onTransition(state => {
      if (state.changed) {
        console.log('state ----> ', state.value);
      }
    }).onDone(() => console.log('done--->')).start();
  }


  async function initiate(context: any) {
    console.log('DbDynamoImpl ::: insert ::: start :::');
    let params: PutItemInput = {
      TableName: 'test',
      Item: context
    };
    try {
      const response = await new DynamoDB.DocumentClient().put(params).promise();
      console.log('DbDynamoImpl ::: insert ::: response :::', response);
      return true;
    } catch (e) {
      console.log("DynamoDb insert error", e);
      return false;
    }
  }

};

标签： node.jsamazon-web-servicesaws-lambdaserverlessxstate

Answer 1

将机器解释和交互包装成一个 Promise 允许您等待状态机达到最终状态。

大致是这样的

export const recordProcessor: Handler = async (event) => {
  console.log('records size----->', event.Records.length);
  for (const record of event.Records) {
      const body = JSON.parse(record.body);
      console.log('body ----->', body);
      await setupMachine(...);
...
}

function setupMachine(...){
  return new Promise((resolve, reject) => {
    interpret(Machine({id:'test',
      context:body,
      initial: 'start',
      states:{
        start: {
          invoke: {
            src: context => initiate(context),
            onDone: {
              target: 'success'
            }
          }
        },
        success: {
          type: 'final'
        }
      }
    })).onTransition(state => {
      if (state.changed) {
        console.log('state ----> ', state.value);
      }
    })
     .onDone(() => { console.log('done--->'); return resolve()})
     .onStop(() => reject());
     .start();
   }
  });
}