AWS Lambda: Write data to DynamoDB with nodejs 8.1

Question

The following code works fine in nodejs 6.1

console.log('Starting function registration');

const AWS = require('aws-sdk');
AWS.config.update({region: 'eu-central-1'});
const docClient = new AWS.DynamoDB({apiVersion: '2012-10-08'});

exports.handler = function(event, context, callback) {

    var params = {
      'TableName' : 'services',
      'Item': {
         'name': {S: 'test'},
         'phone': {S: '0742324232'},
         'available': {BOOL: true}
         }
    };  

    docClient.putItem(params, function(err, data) {
      if (err) {
        console.log("Error", err);
        callback(err);
      } else {
        console.log("Success", data);
        callback(data);
     }});
};

Yet, when trying to use it in nodejs 8.1 style, It doesn't write anything to the database:

console.log('Starting function registration');

const AWS = require('aws-sdk');
AWS.config.update({region: 'eu-central-1'});
const docClient = new AWS.DynamoDB({apiVersion: '2012-10-08'});

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

    var params = {
      'TableName' : 'services',
      'Item': {
         'name': {S: 'test2'},
         'phone': {S: '0742324232'},
         'available': {BOOL: false}
         }
    };  

    var {err, data} = await docClient.putItem(params);
    return data;
};

I feel like I'm missing something about the usage of async/await but can't figure out what. What's the proper way to write an item to DynamoDB using nodejs 8.1 and lambda functions?

Have you tried checking the value of err to see what the issue is? — Mark B

nerdier.js nerdier.js · Accepted Answer · 2018-07-14T13:36:24

It would not work with plaintiff async/ await because putItem ( or, in general, any of the dynamdb methods if you us them via the aws-sdk ) is a callback method where it returns the data and the error. Async / await works with promises and not callbacks.

You may wish to promisify the dynamodb methods to make them work with async / await.

AWS Lambda: Write data to DynamoDB with nodejs 8.1

1 Answers