AWS Lambda using node.js not executing promise function

Question

I created this simple function with two console.log calls. "After promise created" shown in log, while "scan promise executed" does not appear. I am new to node.js. Where is my mistake?

exports.handler = async(event, context) => {

    var AWS = require("aws-sdk");

    AWS.config.update({
        region: "us-east-1",
        endpoint: "https://dynamodb.us-east-1.amazonaws.com"
    });

    var docClient = new AWS.DynamoDB.DocumentClient();



    var params = {
        TableName: "User",
        KeyConditionExpression: null,
        FilterExpression: 'CusomerId = :customerid',

    };



    var scanPromise=docClient.scan(params).promise();
    console.log('\r\nAfter promise created');
    scanPromise.then(function(err,data)
    {
         console.log('\r\nScan promise executed');

    });
};

Have you tried returning scanPromise from the function. e.g. return scanPromise.then(.....) — euvs
– euvs, Commented Dec 8, 2018 at 1:36
Ok that does cause the promise to execute. Although it causes a dynamodb access failure in log without hitting the console.log line in my code. If you enter this in answer I can mark as answered. — jhurtas
– jhurtas, Commented Dec 8, 2018 at 1:48

euvs · Accepted Answer · 2018-12-08 02:05:01Z

1

Your handler is an asynchronous function. If you don't return a promise, the handler will be executed but it will quit immediately without waiting for your promise to finish.

Change it to return scanPromise.then(...)

answered Dec 8, 2018 at 2:05

euvs

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1 Comment

dillon.harless Over a year ago

I have a similar issue, but this does not work for me. I've written it exactly as you suggested and posted a question here: stackoverflow.com/questions/55518992/… Could you provide any feedback?

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