Book Image

AWS Lambda Quick Start Guide

By : Markus Klems
5 (1)
Book Image

AWS Lambda Quick Start Guide

5 (1)
By: Markus Klems

Overview of this book

AWS Lambda is a part of AWS that lets you run your code without provisioning or managing servers. This enables you to deploy applications and backend services that operate with no upfront cost. This book gets you up to speed on how to build scalable systems and deploy serverless applications with AWS Lambda. The book starts with the fundamental concepts of AWS Lambda, and then teaches you how to combine your applications with other AWS services, such as AmazonAPI Gateway and DynamoDB. This book will also give a quick walk through on how to use the Serverless Framework to build larger applications that can structure code or autogenerate boilerplate code that can be used to get started quickly for increased productivity. Toward the end of the book, you will learn how to write, run, and test Lambda functions using Node.js, Java, Python, and C#.
Table of Contents (8 chapters)

Testing and debugging Lambda functions

In the previous section, we learned about programming Lambda function handlers. Now, let's explore testing and debugging.

Here, we are going to look at three different testing and debugging approaches:

  • Using the Serverless framework
  • Using Postman for testing our API
  • Using the AWS Management Console

Let's go back to our handler.js file from the previous section. There are a couple things that should be changed. The response method should be changed back to something that our API can work with.

Give it a body property with a stringify JSON content, as shown here:

body: JSON.stringify({

And, in the JSON content, get back the event in the remaining time from the context, and then, instead of returning an error, we will return the response:

'use strict';
module.exports.hello = (event, context, callback) => {
let remainingTime...