AWS Lambda Introduction

Lesson Objectives

By the end of this lesson, you will:

1. Understand what AWS Lambda is and its role in serverless computing.
2. Learn the key features and benefits of AWS Lambda.
3. Explore use cases for AWS Lambda in real-world scenarios.
4. Create and deploy your first AWS Lambda function.

Introduction: Computing Without Servers

Imagine you’re building a new feature for your application—a file upload processor. Traditionally, you’d set up a server, configure it, and ensure it runs 24/7, even though the feature might only be used occasionally. Wouldn’t it be better if you could write code that runs only when triggered and pay only for the time it’s executing?

This is exactly what AWS Lambda offers. It’s a serverless compute service that lets you run code in response to events without provisioning or managing servers.

What is AWS Lambda?

AWS Lambda is a serverless computing service that automatically manages the underlying infrastructure for running your code. You only need to focus on writing the code, and AWS handles the rest.

Key Features:

1. Event-Driven: Lambda functions are triggered by events like file uploads to S3, API requests, or database updates.
2. Automatic Scaling: Lambda automatically scales to handle thousands of requests simultaneously.
3. Pay-As-You-Go: You’re billed only for the compute time your function uses—measured in milliseconds.
4. Language Support: Supports multiple programming languages, including Python, Node.js, Java, Go, and C#.

Why Use AWS Lambda?

1. No Server Management: Forget about managing, patching, or scaling servers.
2. Cost Efficiency: Pay only for the time your code runs, making it ideal for sporadic workloads.
3. Flexibility: Integrates seamlessly with other AWS services like S3, DynamoDB, and API Gateway.
4. Scalability: Automatically handles scaling, whether you’re processing one request or a million.

Common Use Cases

1. Real-Time File Processing:
   • Example: A Lambda function triggered by an S3 file upload to resize images or extract metadata.
2. API Backends:
   • Example: Use AWS Lambda with API Gateway to build serverless REST APIs.
3. Data Transformation:
   • Example: Process data streams from Amazon Kinesis or DynamoDB.
4. Automation:
   • Example: Trigger a Lambda function to clean up resources when an EC2 instance is terminated.

Step-by-Step Guide to Deploying a Lambda Function

Scenario: Building a Simple “Hello, World!” Lambda Function

Step 1: Navigate to the AWS Lambda Console

1. Log in to the AWS Management Console.
2. In the search bar, type Lambda and select the Lambda service.

Step 2: Create a New Lambda Function

1. Click Create Function.
2. Choose Author from Scratch.
   • Function Name: Enter HelloWorldLambda.
   • Runtime: Choose Python 3.9 (or any supported runtime you prefer).
3. Click Create Function.

Step 3: Write Your Lambda Code

1. Scroll down to the Function Code section.
2. Replace the default code with the following:

   
   import json
   def lambda_handler(event, context):
   return {
   ‘statusCode’: 200,
   ‘body’: json.dumps(‘Hello, World from AWS Lambda!’)
   }
   

3. Click Deploy to save your changes.

Step 4: Create a Test Event

1. Click Test at the top of the screen.
2. Configure a new test event:
   • Event Template: Choose Hello World.
   • Event Name: Enter TestEvent.
3. Save the test event.

Step 5: Test the Function

1. Click Test to run the Lambda function.
2. View the output in the Execution Result section. You should see:

{
“statusCode”: 200,
“body”: “Hello, World from AWS Lambda!”
}

Step 6: Make the Lambda Function Triggerable

1. Add a Trigger:
   • In the Designer section, click Add Trigger.
   • Choose API Gateway.
2. Configure API Gateway:
   • Choose HTTP API.
   • Click Add to save the trigger.
3. Invoke the Function:
   • Copy the API Gateway endpoint URL.
   • Paste it into a browser or use a tool like Postman to send an HTTP GET request.
   • You should see the Hello, World! response.

Reflection: Why AWS Lambda?

AWS Lambda allows you to focus on writing code without worrying about infrastructure. It’s perfect for event-driven workloads and integrates seamlessly with other AWS services, making it a versatile tool for developers and businesses alike.

In this lesson, you deployed a simple Lambda function and tested it. From here, you can build more complex functions to solve real-world problems.

What’s Next?

In the next chapter, we’ll dive into AWS Storage Solutions, starting with Amazon S3, where you’ll learn to store and manage data efficiently.

Your serverless journey has begun—let’s keep building!