UI Testing using Selenium WebDriver and Chrome inside AWS Lambda

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What is AWS Lambda?

Amazon explains, AWS Lambda (λ) as a ‘serverless’ compute service, meaning the developers, don’t have to worry about which AWS resources to launch, or how will they manage them, they just put the code on lambda and it runs, it’s that simple! It helps you to focus on core-competency i.e. App Building or the code.

Where will I use AWS Lambda?

AWS Lambda executes your backend code, by automatically managing the AWS resources. When we say ‘manage’, it includes launching or terminating instances, health checkups, auto scaling, updating or patching new updates etc.

So, how does it work?

The code that you want Lambda to run is known as a Lambda function. Now, as we know a function runs only when it is called, right? Here, Event Source is the entity which triggers a Lambda Function, and then the task is executed.

Where to use Lambda?

You can use it with multiple services

And also you can use it with Chatbot

Pricing in AWS Lambda

Like most of the AWS services, AWS Lambda is also a pay per use service, meaning you only pay what you use, therefore you are charged on the following parameters

The number of requests that you make to your lambda function
The duration for which your code executes.

* Source: AWS official website

How to use Selenium Webdriver and Chrome inside AWS Lambda?

Note:

We will use Chromium version 62 in headless mode
You need to have AWS Account , if you don’t have one you can your own account from this link

https://aws.amazon.com/free/

1- Login to AWS Management Console and Select AWS Lambda from Compute Services

2- Click on Create new a function

3- Select option Create from scratch (default select)

4- Add the function name and create new role and click on Create Button

5- Congratulation you create your first Lambda function

6- Select that you will upload the code from .zip folder

7- upload the file that you downloaded from this link

node_lambda_function.zip

The code contains a node.js code that running selenium script using chrome in headless mode and get the page title from the url

'use strict';

exports.handler = (event, context, callback) => {
    var webdriver = require('selenium-webdriver');
    var chrome = require('selenium-webdriver/chrome');
    var builder = new webdriver.Builder().forBrowser('chrome');
    var chromeOptions = new chrome.Options();
    const defaultChromeFlags = [
        '--headless',
        '--disable-gpu',
        '--window-size=1280x1696', // Letter size'--no-sandbox',
        '--user-data-dir=/tmp/user-data',
        '--hide-scrollbars',
        '--enable-logging',
        '--log-level=0',
        '--v=99',
        '--single-process',
        '--data-path=/tmp/data-path',
        '--ignore-certificate-errors',
        '--homedir=/tmp',
        '--disk-cache-dir=/tmp/cache-dir'
    ];

    chromeOptions.setChromeBinaryPath("/var/task/lib/chrome");
    chromeOptions.addArguments(defaultChromeFlags);
    builder.setChromeOptions(chromeOptions);

    var driver = builder.build();
    driver.get(event.url);
    driver.getTitle().then(function(title) {

        console.log("Page title for " + event.url + " is " + title)
        callback(null, 'Page title for ' + event.url + ' is ' + title);
    });

    driver.quit();
};