Tutorial: Create AWS Lambda Functions

1. Introduction

In this tutorial, we will walk you through the steps to create AWS Lambda functions. AWS Lambda is an event-driven, serverless computing platform provided by Amazon as a part of Amazon Web Services.

You will learn how to define a function, specify the runtime, and provide the function code.

Prerequisites:

• Basic knowledge of AWS Services
• Basic programming understanding
• An AWS account

2. Step-by-Step Guide

Let's go through the steps of creating a Lambda function:

1. Sign in to the AWS Management Console.

2. Navigate to the AWS Lambda service.

From the AWS Management Console, click on 'Services' and then select 'Lambda' under 'Compute'.

1. Create a new Lambda function.

Click on the 'Create function' button.

1. Configure the function.

You will be required to specify details for the function:
- Function name: Give your function a unique name.
- Runtime: Choose the language of your code. AWS Lambda supports Node.js, Java, C#, Go and Python.

1. Write your function code.

You can write your function code in the online code editor provided by AWS or upload a .zip file containing your code.

1. Save and test your function.

Click on 'Save' in the top right corner. Then click on 'Test' to run your function and see the result.

Tips:

• Make sure your function does only one thing and does it well.
• Keep your functions stateless.
• Monitor the performance of your functions.

3. Code Examples

Here is an example of a simple Lambda function written in Node.js:

exports.handler = async (event) => {
    // Log the received event
    console.log('Received event:', JSON.stringify(event, null, 2));

    // Return a 200 response
    const response = {
        statusCode: 200,
        body: JSON.stringify('Hello from Lambda!'),
    };

    return response;
};

This function logs the received event and returns a "Hello from Lambda!" message with a 200 HTTP status code. If you run this function, you should see the logged event in the AWS console and receive the response.

4. Summary

In this tutorial, we have covered how to create AWS Lambda functions, specify the runtime, and provide the function code.

Next, you can explore how to trigger your Lambda function by different AWS services like S3, DynamoDB, etc.

For more detailed information, refer to the official AWS Lambda developer guide.

5. Practice Exercises

1. Create a Lambda function that returns the current date and time.

   Hint: Use the Date object in JavaScript.

2. Create a Lambda function that takes a string as input and returns the reversed string.

   Hint: Use the split, reverse, and join functions in JavaScript.

Remember, the more you practice, the more you learn. Happy coding!