Building and Triggering an AWS Lambda Function for Beginners!

Lambda can be used in many things

1. Data Processing

• Process real-time streaming data from services like Amazon Kinesis or Amazon SQS.


• Transform and store data in databases or data lakes.

2 Web Applications

• Build and deploy RESTful APIs with AWS API Gateway.


• Serve as backend logic for lightweight web apps.

3 Event-Driven Tasks

• Trigger tasks such as image resizing, sending notifications, or cleaning logs when files are uploaded to S3

In this guide, we'll explore AWS Lambda, create a basic function, test it, and finally implement a useful notification simulation.

Now we're going to test the AWS Lambda and to do this we need to set up a few things. Follow these steps:

Step 1: Create a Lambda Function

1. Log in to the AWS Management Console
   
   Go to

   
   
   

   4 In the Basic Information pane let's name it 'myLambdaFunction'
   
   Note: You can name it the way you want

   
   
   

   5 For Runtime, choose either Node.js 22.x or Python 3.13.
   
   In this case I'll be using Node.js

   
   
   

   After setting up that should look like this
   
   

   
   

   
   
   
   Step 2: Create a simple testing code
   

   
   
   

   This snippet came from the documentation as a way to test waters but later, I will show some application
   
   

   
   
   
   
   

   CODE Kopieren

   export const handler = async (event, context) => {
   
   
   
     const length = event.length;
   
   
   
     const width = event.width;
   
     let area = calculateArea(length, width);
   
     console.log(`The area is ${area}`);
   
   
   
     console.log('CloudWatch log group: ', context.logGroupName);
   
   
   
     let data = {
   
       "area": area,
   
     };
   
       return JSON.stringify(data);
   
   
   
     function calculateArea(length, width) {
   
       return length * width;
   
     }
   
   };
   
   

   
   
   
   
   
   
   
   
   
   
   • Deploy the code by clicking Deploy
     
   
   
   
   
   
   
   
   
   
   1. After clicking that you should see this.
   
   
   
   
   
   
   

   and voila you have tested your first lambda function!

   
   
   

   
   
   
   Now for the last part we're going to create something useful but still faithful to this structure
   

   
   
   

   Now let's change the code with this:
   
   

   
   
   
   
   

   CODE Kopieren

   export const handler = async (event, context) => {
   
   
   
     const { email, password } = event;
   
   
   
     if (!email || !password) {
   
         return {
   
             statusCode: 400,
   
             body: JSON.stringify({ message: "Email and password are required." }),
   
         };
   
     }
   
   
   
     const notiMessage = `Notification sent to: ${email}`;
   
     console.log(notiMessage);
   
     console.log('CloudWatch log group: ', context.logGroupName);
   
     return {
   
         statusCode: 200,
   
         body: JSON.stringify({
   
             message: "Notification triggered successfully.",
   
             details: notiMessage,
   
         }),
   
     };
   
   }
   
   
   
   

   
   
   
   
   
   
   
   

   Here's what this function does.

   
   
   
   
   
   • So first instead of repeatedly typing the event we declared right away all the things we're expecting to come 'email' & 'password'
     
   
   
   • Then create a simple if validation to check if the 'email' & 'password' has a value
   
   
   • We still use the CloudWatch to monitor the logs
   
   
   • And if all goes as planned the body would return a success message that has a binded value of static string and the the details with the binded value of the const notiMessage
     
   
   
   
   
   

   Now for the test event lets just change the keys and values
   
   

   
   
   
   
   

   CODE Kopieren

   {
   
     "email": "[email protected]",
   
     "password": "7hi$isAT3stSimUl5t0n"
   
   }
   
   

   
   
   
   
   
   
   
   

   Then we run it and it should ouput something like this:

   
   
   



2. 
   
   
   
   That's it for our:
   
   Building and Triggering an AWS Lambda Function for Beginners!



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