Top 5 AWS CDK Patterns for Serverless Applications

Are you tired of manually configuring your serverless applications on AWS? Do you want to automate your infrastructure deployment process? If yes, then you have come to the right place. In this article, we will discuss the top 5 AWS CDK patterns for serverless applications.

What is AWS CDK?

AWS Cloud Development Kit (CDK) is an open-source software development framework to define cloud infrastructure in code and provision it through AWS CloudFormation. It allows developers to define their infrastructure using familiar programming languages such as TypeScript, Python, Java, C#, and JavaScript.

Why use AWS CDK for Serverless Applications?

AWS CDK provides several benefits for serverless applications, including:

• Faster Infrastructure Deployment: AWS CDK allows developers to define their infrastructure in code, which can be version-controlled and deployed quickly.
• Reduced Configuration Errors: With AWS CDK, developers can define their infrastructure using familiar programming languages, which reduces the chances of configuration errors.
• Improved Collaboration: AWS CDK allows developers to collaborate on infrastructure development, which improves team productivity and reduces development time.
• Better Resource Management: AWS CDK provides a higher-level abstraction for defining infrastructure, which makes it easier to manage resources and dependencies.

Top 5 AWS CDK Patterns for Serverless Applications

1. Lambda Function with API Gateway: This pattern is used to create a Lambda function and an API Gateway endpoint to trigger the function. The Lambda function can be written in any supported programming language, and the API Gateway endpoint can be configured to accept requests from various sources such as HTTP, WebSocket, or Lambda.

import * as cdk from '@aws-cdk/core';
import * as lambda from '@aws-cdk/aws-lambda';
import * as apigateway from '@aws-cdk/aws-apigateway';

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

    const handler = new lambda.Function(this, 'MyLambdaFunction', {
      runtime: lambda.Runtime.NODEJS_12_X,
      code: lambda.Code.fromAsset('lambda'),
      handler: 'index.handler',
    });

    const api = new apigateway.RestApi(this, 'MyApiGateway', {
      restApiName: 'My API Gateway',
    });

    const integration = new apigateway.LambdaIntegration(handler);

    api.root.addMethod('GET', integration);
  }
}

2. Lambda Function with S3 Event: This pattern is used to create a Lambda function that is triggered by an S3 event. The Lambda function can be used to process the S3 object and perform various operations such as resizing images, extracting metadata, or converting file formats.

import * as cdk from '@aws-cdk/core';
import * as lambda from '@aws-cdk/aws-lambda';
import * as s3 from '@aws-cdk/aws-s3';
import * as s3n from '@aws-cdk/aws-s3-notifications';

export class LambdaWithS3EventStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const handler = new lambda.Function(this, 'MyLambdaFunction', {
      runtime: lambda.Runtime.NODEJS_12_X,
      code: lambda.Code.fromAsset('lambda'),
      handler: 'index.handler',
    });

    const bucket = new s3.Bucket(this, 'MyS3Bucket', {
      bucketName: 'my-s3-bucket',
    });

    bucket.addEventNotification(s3.EventType.OBJECT_CREATED, new s3n.LambdaDestination(handler));
  }
}

3. Lambda Function with DynamoDB Stream: This pattern is used to create a Lambda function that is triggered by a DynamoDB stream. The Lambda function can be used to process the stream records and perform various operations such as updating indexes, aggregating data, or sending notifications.

import * as cdk from '@aws-cdk/core';
import * as lambda from '@aws-cdk/aws-lambda';
import * as dynamodb from '@aws-cdk/aws-dynamodb';

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

    const handler = new lambda.Function(this, 'MyLambdaFunction', {
      runtime: lambda.Runtime.NODEJS_12_X,
      code: lambda.Code.fromAsset('lambda'),
      handler: 'index.handler',
    });

    const table = new dynamodb.Table(this, 'MyDynamoDBTable', {
      tableName: 'my-dynamodb-table',
      partitionKey: { name: 'id', type: dynamodb.AttributeType.STRING },
    });

    table.addStream('MyDynamoDBStream', {
      streamViewType: dynamodb.StreamViewType.NEW_AND_OLD_IMAGES,
      lambdaFunction: handler,
    });
  }
}

4. Step Function with Lambda Function: This pattern is used to create a Step Function that orchestrates multiple Lambda functions. The Step Function can be used to define the workflow of the application and handle various use cases such as data processing, data validation, or error handling.

import * as cdk from '@aws-cdk/core';
import * as lambda from '@aws-cdk/aws-lambda';
import * as stepfunctions from '@aws-cdk/aws-stepfunctions';
import * as tasks from '@aws-cdk/aws-stepfunctions-tasks';

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

    const firstFunction = new lambda.Function(this, 'MyFirstLambdaFunction', {
      runtime: lambda.Runtime.NODEJS_12_X,
      code: lambda.Code.fromAsset('lambda'),
      handler: 'index.handler',
    });

    const secondFunction = new lambda.Function(this, 'MySecondLambdaFunction', {
      runtime: lambda.Runtime.NODEJS_12_X,
      code: lambda.Code.fromAsset('lambda'),
      handler: 'index.handler',
    });

    const definition = new stepfunctions.Chain([
      new tasks.LambdaInvoke(this, 'InvokeFirstLambdaFunction', {
        lambdaFunction: firstFunction,
      }),
      new tasks.LambdaInvoke(this, 'InvokeSecondLambdaFunction', {
        lambdaFunction: secondFunction,
      }),
    ]);

    const stateMachine = new stepfunctions.StateMachine(this, 'MyStateMachine', {
      definition,
      stateMachineName: 'My State Machine',
    });
  }
}

5. EventBridge Rule with Lambda Function: This pattern is used to create an EventBridge rule that triggers a Lambda function. The EventBridge rule can be used to monitor various events such as CloudTrail events, AWS API events, or custom events.

import * as cdk from '@aws-cdk/core';
import * as lambda from '@aws-cdk/aws-lambda';
import * as events from '@aws-cdk/aws-events';
import * as targets from '@aws-cdk/aws-events-targets';

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

    const handler = new lambda.Function(this, 'MyLambdaFunction', {
      runtime: lambda.Runtime.NODEJS_12_X,
      code: lambda.Code.fromAsset('lambda'),
      handler: 'index.handler',
    });

    const rule = new events.Rule(this, 'MyEventBridgeRule', {
      eventPattern: {
        source: ['aws.ec2'],
        detailType: ['EC2 Instance State-change Notification'],
        detail: {
          state: ['running'],
        },
      },
    });

    rule.addTarget(new targets.LambdaFunction(handler));
  }
}

Conclusion

AWS CDK provides a powerful and flexible way to define and deploy serverless applications on AWS. In this article, we discussed the top 5 AWS CDK patterns for serverless applications, including Lambda Function with API Gateway, Lambda Function with S3 Event, Lambda Function with DynamoDB Stream, Step Function with Lambda Function, and EventBridge Rule with Lambda Function. By using these patterns, you can automate your infrastructure deployment process, reduce configuration errors, improve collaboration, and better manage your resources and dependencies. So, what are you waiting for? Start using AWS CDK for your serverless applications today!

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