S3 Bucket Example in AWS CDK - Complete Guide

Creating an S3 Bucket in AWS CDK #

In this article we are going to cover some of the most common properties we use to create and configure an S3 bucket in AWS CDK.

In order to create an S3 bucket in CDK, we have to instantiate and configure the Bucket class.

Note that all of the props we're going to pass to the bucket in the second example are optional. You could create an S3 bucket in CDK, with a simple one-liner:

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

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

    const s3Bucket = new s3.Bucket(this, 's3-bucket')
  }
}

I'll post the complete code snippet of configuring an S3 bucket in CDK and then we'll go over the details.

import * as s3 from '@aws-cdk/aws-s3';
import * as cdk from '@aws-cdk/core';
import * as iam from '@aws-cdk/aws-iam';

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

    // 👇 create bucket
    const s3Bucket = new s3.Bucket(this, 's3-bucket', {
      // bucketName: 'my-bucket',
      removalPolicy: cdk.RemovalPolicy.DESTROY,
      autoDeleteObjects: true,
      versioned: false,
      publicReadAccess: false,
      encryption: s3.BucketEncryption.S3_MANAGED,
      cors: [
        {
          allowedMethods: [
            s3.HttpMethods.GET,
            s3.HttpMethods.POST,
            s3.HttpMethods.PUT,
          ],
          allowedOrigins: ['http://localhost:3000'],
          allowedHeaders: ['*'],
        },
      ],
      lifecycleRules: [
        {
          abortIncompleteMultipartUploadAfter: cdk.Duration.days(90),
          expiration: cdk.Duration.days(365),
          transitions: [
            {
              storageClass: s3.StorageClass.INFREQUENT_ACCESS,
              transitionAfter: cdk.Duration.days(30),
            },
          ],
        },
      ],
    });

    // 👇 grant access to bucket
    s3Bucket.grantRead(new iam.AccountRootPrincipal());
  }
}

Let's go over what we did in the code snippet.

1. we created a bucket by instantiating the Bucket class

2. the props we've passed to the constructor are:

3. lastly, we have used the grantRead method on the bucket instance to grant read access to the owner of the account, in which the stack was created.

The service-to-service interaction methods, that are exposed by CDK constructs are the main selling point of the service. To grant write permissions on an s3 bucket to a lambda function is as simple as:

s3Bucket.grantWrite(lambda);

All these abstractions, provided by CDK make our code much easier to read and understand (than CloudFormation).

To deploy the bucket, you'd have to execute the deploy command:

npx cdk deploy

If we take a look at the CloudFormation management console, after the deployment, we can see that CDK has provisioned a total of 6 resources for us:

Clean up #

To delete the stack and the provisioned resources, execute the destroy command:

npx cdk destroy

Further Reading #

• AWS CDK Tutorial for Beginners - Step-by-Step Guide
• How does AWS CDK work
• What is a Token in AWS CDK
• CDK Constructs - Complete Guide
• What is an identifier (id) in AWS CDK
• How to use Context in AWS CDK
• How to use Parameters in AWS CDK