Serverless computing is becoming an increasingly popular way to develop and deploy applications. With serverless, developers can focus on writing code and not worry about the underlying infrastructure. AWS Lambda and API Gateway are two popular AWS services used for serverless computing. In this blog post, we will explore how to use AWS CDK to deploy serverless applications using these services.

Getting started with AWS CDK

Before we get into the specifics of building serverless applications, let's start with a brief introduction to AWS CDK. AWS Cloud Development Kit (CDK) is an open-source software development framework for defining cloud infrastructure in code. With AWS CDK, you can define your infrastructure in familiar programming languages such as TypeScript, Python, and Java. AWS CDK uses AWS CloudFormation under the hood, so all of your infrastructure is defined in a CloudFormation stack.

Creating a serverless stack

To create a serverless stack with AWS CDK, we first need to define our resources. In this case, we will be defining an AWS Lambda function and an API Gateway endpoint. Let's start with the Lambda function:

import * as cdk from 'aws-cdk-lib';
import * as lambda from 'aws-cdk-lib/aws-lambda';

export class ServerlessStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const myFunction = new lambda.Function(this, 'MyFunction', {
      runtime: lambda.Runtime.NODEJS_14_X,
      handler: 'index.handler',
      code: lambda.Code.fromAsset('path/to/lambda/code'),
    });
  }
}

In this example, we are defining a new Lambda function with the runtime of Node.js 14.x. We are also specifying the location of the code for the function. This code could be located in a local directory or in an S3 bucket.

Next, we will define the API Gateway endpoint:

import * as apigw from 'aws-cdk-lib/aws-apigatewayv2';

export class ServerlessStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const myFunction = new lambda.Function(this, 'MyFunction', {
      runtime: lambda.Runtime.NODEJS_14_X,
      handler: 'index.handler',
      code: lambda.Code.fromAsset('path/to/lambda/code'),
    });

    const api = new apigw.HttpApi(this, 'MyApi');
    api.addRoutes({
      path: '/',
      methods: [apigw.HttpMethod.GET],
      integration: new apigw.LambdaProxyIntegration({
        handler: myFunction,
      }),
    });
  }
}

In this example, we are defining a new HTTP API Gateway endpoint that routes to our Lambda function. We are specifying that this endpoint should respond to GET requests and forward them to our Lambda function.

Deploying and testing your serverless application

Once we have defined our resources, we can deploy our stack using the AWS CDK CLI:

cdk deploy

This will create the necessary resources in your AWS account. Once the deployment is complete, we can test our API Gateway endpoint by sending an HTTP GET request to the endpoint URL:

curl https://api-gateway-url/

This should return the output from our Lambda function.

Conclusion

In this blog post, we have seen how to use AWS CDK to define and deploy a serverless stack containing an AWS Lambda function and an API Gateway endpoint. With AWS CDK, you can define your infrastructure in code and easily manage it through version control systems and continuous integration/continuous deployment (CI/CD) pipelines. AWS CDK abstracts away the complexity of CloudFormation and provides an intuitive programming interface that makes it easy to create and manage AWS resources.

With AWS CDK, you can take advantage of the benefits of serverless computing, such as automatic scaling and pay-as-you-go pricing. AWS Lambda and API Gateway are just two of the many serverless services provided by AWS, and with AWS CDK, you can easily create and manage these services alongside other AWS services.

In summary, AWS CDK provides an excellent framework for defining and deploying serverless applications. With its intuitive programming interface and integration with AWS CloudFormation, you can easily manage your serverless infrastructure in code. By using AWS CDK, you can take advantage of the benefits of serverless computing, such as automatic scaling and pay-as-you-go pricing, and build reliable and scalable serverless applications.