CODEWITHSUNDEEP
node.jsamazon-web-servicescallbackaws-lambda
CrazyCoder
CrazyCoder

Reputation: 219

AWS NodeJS lambda call within a lambda function

I've trying to call lambda function from another lambda function and get result to execute rest of the lambda.

Basic flow of function is below 

X - main lambda function
    - process A (independent)
    - process C (need input from process B)
    - process D
    - return final dataset 
Y - Child lambda function
   - process B ( need input from process A and respond back to X )

This is my code so far 

var AWS = require('aws-sdk');
AWS.config.region = 'us-east-1';
var lambda = new AWS.Lambda();

const GetUserCheckoutData: Handler = async (userRequest: EmptyProjectRequest, context: Context, callback: Callback) => {

    const dboperation = new UserController();
    const usercheckoutdata = new CheckOutInfo();
    const addresscontroller = new  AddressController();
    const ordercontroller = new OrderController();
    const paypalcreateorder = new PayPalController();

    const userid = await dboperation.getUserID(userRequest.invokeemailAddress);

    usercheckoutdata.useraddressdetails = await addresscontroller.GetListOfAddressByUserID(userid);
    var orderlist = new Array<Order>();
    orderlist = [];

    orderlist =  await ordercontroller.GetCurrentOrder(userid);

    console.log("Order Complete");

    var params = {
        FunctionName: 'api-ENGG-SellItem', // the lambda function we are going to invoke
        InvocationType: 'RequestResponse',
        LogType: 'Tail',
        Payload: '{ "orderlist" : xxxxxxx }'
      };

    lambda.invoke(params, (err:any, res:any) => {
        if (err) {
            callback(err);
        }

        console.log(JSON.stringify(res));

        callback(null, res.Payload);
    });

    usercheckoutdata.orderID = await paypalcreateorder.CreateOrder(userid , orderlist);
    usercheckoutdata.orderPreview = await ordercontroller.OrderPreview(userid);


    //callback(null,usercheckoutdata);
};

export { GetUserCheckoutData }

I tried a few different ways but flow is not working properly. cross lambda function is executing. but cannot get the response on time.

My child lambda function demo code

import { Handler, Context } from "aws-lambda";

const SellItem: Handler = (event, context, callback) => {

    context.callbackWaitsForEmptyEventLoop = false;
    console.log("Other Lambda Function");
    setTimeout(() => {

        callback(null, "My name is Jonathan"); 
     }, 1000 * 10); // 10 seconds delay
}

export {SellItem}

I think since I don't have much NodeJS knowledge this is happening. don't know how to put call back in right way I guess. Any help will be appreciated

Upvotes: 1

Views: 1162

Answers (1)

Jason Wadsworth
Jason Wadsworth

Reputation: 8887

You should make your call to the second lambda a promise, so you can await it.

    const res = await lambda.invoke(params).promise();

    // do things with the response

Upvotes: 2

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