Here, we are going to take a look at the Serverless framework documentation. We will then take a look at how to install it, and then we'll try out our first commands.

Go to the main landing page of the Serverless framework, serverless.com.

To find all the information that you need, click on Quick Start Docs. For now, let's take a quick look at the installation section. The first thing that you need to have installed is Node.js, and you will find some information on how to install it on your local machine. For programming serverless, we need Node.js version 4 or higher. If you don't have Node.js already, please do so now, and then resume.

In the previous section, we installed the Serverless framework and tried out the command line. Now, let's create our first serverless project. We are going to use the Serverless framework to create a simple Node.js lambda function and a REST API. Open Terminal and create a directory where you can place your serverless project files. I named it app, but you can name it whatever you want. Go to that directory and open your preferred IDE. I used the Atom editor. When the Atom editor was opened in my empty directory, I used an Atom package at terminal plus to open a new Terminal window inside my IDE. This makes it easier because I don't need to switch between writing code and typing in commands. So, let's type in a command to scaffold a serverless service:

serverless create --template aws-nodejs

The command for creating a service is created...

Now, let's learn a little bit more about programming Lambda functions with Node.js. We are going to take a closer look at the function handler, and in particular its arguments, that is:

• Event objects
• Context objects
• Callback objects

Open the handler.js file and delete the code that's in the function body. One way to learn about the event and context object would be to log them out on the console:

'use strict';
module.exports.hello = (event, context, callback) => {
    console.log('event is', event);
};

Let's see what this gives us.

I am invoking the function locally to see what the output is with the function name set as hello:

sls invoke local -f hello
event is

Ok, my event, apparently, is null. Let's see what the context is, as shown next:

module.exports.hello = (event, context, callback) =&gt...

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...

In this chapter, we learned how to use the Serverless framework to create and test Lambda functions and APIs, and we tried out different approaches for API testing, Lambda testing, and debugging. Now, we have all the things necessary to build a real application, so in the next chapter, that's what we are going to do, by building a serverless application.