Automating AWS Lambda Deployments with AWS CDK

Table of Contents

1. Introduction

In today’s fast-paced tech environment, automation is no longer a luxury; it’s a necessity. Among the numerous tools and services available, the AWS Cloud Development Kit (CDK) stands out as a game-changer for infrastructure automation, enabling developers to define cloud resources using familiar programming languages. Combined with AWS Lambda, a serverless compute service that lets you run your code without provisioning or managing servers, you get a powerful duo that can streamline your cloud operations and boost your application’s performance. This article aims to guide you through automating AWS Lambda deployments using AWS CDK.

2. Prerequisites

To get the most out of this guide, you should have:

A basic understanding of AWS services and concepts. Check out our various AWS posts to get started.
An AWS account set up and properly configured.
Familiarity with a programming language supported by AWS CDK, such as TypeScript or Python. (We’ll use Typescript in this article)
AWS CDK CLI installed and set up on your development environment. Check out our guide on setting up AWS CDK CLI.

3. Understanding AWS CDK

The AWS Cloud Development Kit (CDK) is an open-source software development framework that allows you to model and provision your cloud application resources using familiar programming languages. You define your resources using AWS CDK constructs, which represent cloud components. These constructs are then grouped into stacks, which are deployed as unit. Finally, one or more stacks form an AWS CDK app.

Using AWS CDK comes with several benefits. It allows you to define your infrastructure in code (Infrastructure as Code or IaC), making it reproducible and version-controllable.

CDK also allows you to leverage the power of modern programming languages, including conditionals, loops, and object-oriented constructs, making your infrastructure more flexible and maintainable.

Read more about AWS CDK in our comprehensive CDK guide.

4. Overview of AWS Lambda

AWS Lambda is a serverless computing service that lets you run your code without thinking about servers. You simply upload your code, and Lambda takes care of everything required to run and scale your code with high availability. It can be triggered by various AWS services like Amazon S3, Amazon DynamoDB, and Amazon API Gateway, or it can be used to automatically run your code in response to events.

Use cases for AWS Lambda are broad and include data transformation, real-time file processing, and even backends for web, mobile, or IoT applications. The benefits are compelling – there’s no server management, continuous scaling, and you only pay for the compute time you consume.

For a deeper understanding of AWS Lambda, you can refer to our detailed Lambda guide.

5. AWS CDK Setup

First, let’s set up AWS CDK on your local machine. You’ll need to install Node.js and AWS CDK CLI:

npm install -g aws-cdk

After that, let’s initialize a new AWS CDK project:

cdk init app --language typescript

This command creates a new directory with an AWS CDK app written in TypeScript.

6. Writing your First AWS Lambda Function

Now, let’s create our AWS Lambda function. We’ll write a simple function that returns a greeting message. The following code is written in Node.js:

exports.handler = async (event) => {
    const response = {
        statusCode: 200,
        body: JSON.stringify('Hello from Lambda!'),
    };
    return response;
};

In this code, we’re defining a handler function that AWS Lambda can call when the service executes your code.

7. Using AWS CDK to Deploy AWS Lambda Function

Having written our Lambda function, it’s time to use AWS CDK to deploy it. We’ll need to write AWS CDK constructs in our stack.ts file:

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

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

        // Define the Lambda function
        const myFunction = new lambda.Function(this, 'MyLambdaFunction', {
            runtime: lambda.Runtime.NODEJS_12_X,
            code: lambda.Code.fromAsset('lambda'),
            handler: 'myFunction.handler',
        });
    }
}

In this code, we’re defining an AWS Lambda function construct using the @aws-cdk/aws-lambda library. We’re setting the runtime to Node.js, the code to our lambda function, and the handler to the exported handler function in our code.

8. Building and Deploying AWS CDK App

Once you’ve defined the Lambda function using AWS CDK constructs, you can synthesize a CloudFormation template and deploy it to AWS:

cdk synth
cdk deploy

These commands generate a CloudFormation template (cdk synth) and deploy your AWS CDK application (cdk deploy). After successful execution, your AWS Lambda function is up and running in your AWS environment. For a detailed discussion on synthesizing and deploying AWS CDK apps, check our AWS CDK Deployment guide.

9. Updating and Managing AWS Lambda Functions with AWS CDK

Managing AWS Lambda functions becomes easier with AWS CDK. Whether you’re updating your function’s code or managing versions and aliases, AWS CDK simplifies these tasks.

Updating the Lambda Function

To update your function, you simply need to make the necessary changes to your code, and then run cdk deploy again. AWS CDK handles the deployment of the updated code to AWS Lambda.

// Update the Lambda function code
exports.handler = async (event) => {
    const response = {
        statusCode: 200,
        body: JSON.stringify('Hello again from Lambda!'),
    };
    return response;
};

After updating your function, run:

cdk deploy

AWS CDK will update the existing Lambda function with your new code.

Versioning and Aliases

AWS CDK also simplifies the task of managing versions and aliases of your Lambda functions. Here’s how you can create a new version of your function:

const version = myFunction.addVersion('v1');

And here’s how you can create an alias that points to this version:

const alias = new lambda.Alias(this, 'MyLambdaAlias', {
    aliasName: 'Prod',
    version,
});

With AWS CDK, it’s easy to manage multiple versions of your function and easily switch between them using aliases.

10. Conclusion

Automating AWS Lambda deployments with AWS CDK is a great way to streamline your development process, manage your resources more effectively, and make your serverless applications more scalable and reliable. In this guide, we explored the basics of AWS CDK and AWS Lambda, how to set them up, how to deploy a Lambda function using AWS CDK, and how to manage your function after it’s deployed. With this knowledge in hand, you’re ready to start automating your AWS operations and take your cloud development to the next level.