How to Set Up Serverless Functions for Event-Driven Applications

Overview:

Developers can execute code in response to events using serverless computing, a cloud-native execution approach, without having to create or manage servers. In serverless designs, the infrastructure, scaling, and resource allocation are dynamically managed by the cloud provider (like AWS). Developers write business logic only. This is made possible by AWS Lambda, which launches backend code automatically in response to HTTP requests, file uploads to S3, and DynamoDB database modifications. Serverless is a strong paradigm for event-driven and microservice-based architectures since it also easily interfaces with other AWS services.

Following steps are:

1. Select a Platform Without Servers
A number of cloud platforms provide serverless compute services, including:
Multiple runtimes are supported by AWS Lambda, which is closely connected with the AWS environment.

• Azure Functions – Azure Functions supports Python, JavaScript, C#, and other languages and integrates seamlessly with Azure services.
• Google Cloud Functions – Google Cloud Functions is compatible with Firebase and GCP services.
  We will concentrate on AWS Lambda for this course because it is quite configurable and extensively used.

2. Build a Lambda function.
In order to construct your Lambda function:
Go to the Lambda service in the AWS Management Console.

Choose “Author from scratch” after clicking on “Create function.”

• Function name: A distinctive moniker for your function.
• Runtime environment: Select the runtime that you want to use, such as Python 3.12, Node.js 20.x, Java 17, etc.
• Execution role: Give the function access to AWS services (such S3 and CloudWatch Logs) by assigning or creating an IAM role.

3. Compose Your Role Code
With Lambda, you can: Quick functions can be written immediately in the inline editor.
Add your application’s dependencies and logic in a.zip file.
To manage common libraries among functions, use AWS Lambda Layers.
Use Infrastructure as Code (IaC) or CI/CD technologies to deploy (e.g., AWS SAM, Serverless Framework, Terraform).

def lambda_handler(event, context):
    return {
        'statusCode': 200,
        'body': 'Setting Server'
    }

4. Configure Triggers

• Event sources must initiate a Lambda function. To expose your function as a web endpoint, use an API gateway (REST or HTTP APIs).
• When files are uploaded (PUT), removed, or altered, Amazon S3 is triggered.
• When data is added, modified, or removed, Lambda is called by Amazon DynamoDB Streams.
• Previously known as CloudWatch Events, EventBridge is used for rule-based or time-based (cron) triggers.
• For asynchronous message-driven workloads, use SQS/SNS.
• Navigate to your Lambda function in the console to set up a trigger.
• Select the “Add Trigger” option under the “Configuration” tab.
• You can test your function within the Lambda console:

  Click on “Test”.