Building Applications with AWS Lambda

Tutorial 2 of 5

Introduction

Goal of the Tutorial

This tutorial aims to guide you through the process of building applications with AWS Lambda.

Learning Outcomes

By the end of this tutorial, you will be able to create, deploy, and manage AWS Lambda functions.

Prerequisites

Before starting, you should have a basic understanding of AWS (Amazon Web Services) and JavaScript (Node.js), as we will be using these in our examples.

Step-by-Step Guide

What is AWS Lambda?

AWS Lambda is a serverless compute service that allows you to run your code without provisioning or managing servers. You can execute your code for virtually any type of application or backend service - all with zero administration.

Creating a Lambda Function

  1. Sign into the AWS Management Console and open the AWS Lambda console.
  2. Choose 'Create function'.
  3. In the 'Create function' page, select 'Author from scratch'.
  4. Specify your function name, runtime (choose Node.js), and create a new role with basic Lambda permissions.
  5. After this, click 'Create function'.

Deploying a Lambda Function

After creating your function, you can add code to your Lambda function by adding an inline code editor in the AWS Management Console.

Managing Lambda Functions

You can configure your Lambda function's concurrency, fine-tune its performance, or add triggers and destinations in the designer section on the AWS Lambda console.

Code Examples

Example 1: Hello World

Here's a basic example of a Lambda function.

exports.handler = async (event) => {
    // The output here is sent to AWS CloudWatch Logs
    console.log('Hello, World!');
    const response = {
        statusCode: 200,
        body: JSON.stringify('Hello, World!'),
    };
    return response;
};

This function simply returns a 'Hello, World!' message with a status code of 200. The function handler takes in an event parameter, which can contain event data if your Lambda function is configured to respond to events.

Summary

In this tutorial, we covered the basics of AWS Lambda: creating, deploying, and managing functions. We've also given you a simple example of a Lambda function.

Next Steps

To further your knowledge, you can look into integrating your Lambda functions with other AWS services such as API Gateway or DynamoDB.

Additional Resources

  1. AWS Lambda Developer Guide
  2. AWS Lambda Functions

Practice Exercises

  1. Create a Lambda function that takes in two numbers as parameters and returns their sum.
  2. Create a Lambda function that is triggered by an S3 bucket event.
  3. Integrate your Lambda function with API Gateway and test the API.

Solutions

  1. Sum of two numbers:
exports.handler = async (event) => {
    let num1 = event.number1;
    let num2 = event.number2;
    let sum = num1 + num2;
    const response = {
        statusCode: 200,
        body: JSON.stringify('Sum: ' + sum),
    };
    return response;
};
  1. S3 bucket trigger:

This needs to be done from the AWS console. Go to your Lambda function, add a trigger, select S3, and follow the instructions.

  1. API Gateway integration:

This also needs to be done from the AWS console. Go to your Lambda function, add a trigger, select API Gateway, and follow the instructions.