Before you begin Add optional parameter Define the stack class Create two stack instances Synthesize and deploy the stack Clean up

Create an app with multiple stacks

Most of the code examples in the AWS CDK Developer Guide involve only a single stack. However, you can create apps containing any number of stacks. Each stack results in its own AWS CloudFormation template. Stacks are the unit of deployment: each stack in an app can be synthesized and deployed individually using the cdk deploy command.

This topic illustrates the following:

How to extend the Stack class to accept new properties or arguments
How to use these properties to affect what resources the stack contains and their configuration
How to instantiate multiple stacks from this class

The example uses a Boolean property, named encryptBucket (Python: encrypt_bucket). It indicates whether an Amazon S3 bucket should be encrypted. If so, the stack enables encryption using a key managed by AWS Key Management Service (AWS KMS). The app creates two instances of this stack, one with encryption and one without.

Before you begin

First, install Node.js and the AWS CDK command line tools, if you haven't already. See Getting started with the AWS CDK for details.

Next, create an AWS CDK project by entering the following commands at the command line.

Add optional parameter

The props argument of the Stack constructor fulfills the interface StackProps. In this example, we want the stack to accept an additional property to tell us whether to encrypt the Amazon S3 bucket. We should create an interface or class that includes the property. This allows the compiler to make sure that the property has a Boolean value and enables autocompletion for it in your IDE.

So open the indicated source file in your IDE or editor and add the new interface, class, or argument. The code should look like this after the changes. The lines we added are shown in bold.

TypeScript

File: lib/multistack-stack.ts


import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';

interface MultiStackProps extends cdk.StackProps {
  encryptBucket?: boolean;
}

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

    // The code that defines your stack goes here
  }
}

JavaScript

File: lib/multistack-stack.js

JavaScript doesn't have an interface feature; we don't need to add any code.


const cdk = require('aws-cdk-stack');

class MultistackStack extends cdk.Stack {
  constructor(scope, id, props) {
    super(scope, id, props);

    // The code that defines your stack goes here
  }
}

module.exports = { MultistackStack }

Python

File: multistack/multistack_stack.py

Python does not have an interface feature, so we'll extend our stack to accept the new property by adding a keyword argument.


import aws_cdk as cdk
from constructs import Construct

class MultistackStack(cdk.Stack):

    # The Stack class doesn't know about our encrypt_bucket parameter,
    # so accept it separately and pass along any other keyword arguments.
    def __init__(self, scope: Construct, id: str, *, encrypt_bucket=False,
                 **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        # The code that defines your stack goes here

Java

File: src/main/java/com/myorg/MultistackStack.java

It's more complicated than we really want to get into to extend a props type in Java. Instead, write the stack's constructor to accept an optional Boolean parameter. Because props is an optional argument, we'll write an additional constructor that lets you skip it. It will default to false.


package com.myorg;

import software.amazon.awscdk.Stack;
import software.amazon.awscdk.StackProps;
import software.constructs.Construct;

import software.amazon.awscdk.services.s3.Bucket;

public class MultistackStack extends Stack {
    // additional constructors to allow props and/or encryptBucket to be omitted
    public MultistackStack(final Construct scope, final String id, boolean encryptBucket) {
        this(scope, id, null, encryptBucket);
    }
    
    public MultistackStack(final Construct scope, final String id) {
        this(scope, id, null, false);
    }

    public MultistackStack(final Construct scope, final String id, final StackProps props,
            final boolean encryptBucket) {
        super(scope, id, props);

        // The code that defines your stack goes here
    }
}

C#

File: src/Multistack/MultistackStack.cs


using Amazon.CDK;
using constructs;

namespace Multistack
{
    

    public class MultiStackProps : StackProps
    {
        public bool? EncryptBucket { get; set; }
    }


    public class MultistackStack : Stack
    {
        public MultistackStack(Construct scope, string id, MultiStackProps props) : base(scope, id, props)
        {
            // The code that defines your stack goes here
        }
    }
}

The new property is optional. If encryptBucket (Python: encrypt_bucket) is not present, its value is undefined, or the local equivalent. The bucket will be unencrypted by default.

Define the stack class

Now let's define our stack class, using our new property. Make the code look like the following. The code you need to add or change is shown in bold.

TypeScript

File: lib/multistack-stack.ts


import * as cdk from 'aws-cdk-lib';
import { Construct } from constructs;
import * as s3 from 'aws-cdk-lib/aws-s3';

interface MultistackProps extends cdk.StackProps {
  encryptBucket?: boolean;
}

export class MultistackStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: MultistackProps) {
    super(scope, id, props);
    
    // Add a Boolean property "encryptBucket" to the stack constructor.
    // If true, creates an encrypted bucket. Otherwise, the bucket is unencrypted.
    // Encrypted bucket uses KMS-managed keys (SSE-KMS).
    if (props && props.encryptBucket) {
      new s3.Bucket(this, "MyGroovyBucket", {
        encryption: s3.BucketEncryption.KMS_MANAGED, 
        removalPolicy: cdk.RemovalPolicy.DESTROY
      });
    } else {
      new s3.Bucket(this, "MyGroovyBucket", {
        removalPolicy: cdk.RemovalPolicy.DESTROY});
    }
  }
}

JavaScript

File: lib/multistack-stack.js


const cdk = require('aws-cdk-lib');
const s3 = require('aws-cdk-lib/aws-s3');

class MultistackStack extends cdk.Stack {
  constructor(scope, id, props) {
    super(scope, id, props);
    
    // Add a Boolean property "encryptBucket" to the stack constructor.
    // If true, creates an encrypted bucket. Otherwise, the bucket is unencrypted.
    // Encrypted bucket uses KMS-managed keys (SSE-KMS).
    if ( props && props.encryptBucket) {
      new s3.Bucket(this, "MyGroovyBucket", {
        encryption: s3.BucketEncryption.KMS_MANAGED, 
        removalPolicy: cdk.RemovalPolicy.DESTROY
      });
    } else {
      new s3.Bucket(this, "MyGroovyBucket", {
        removalPolicy: cdk.RemovalPolicy.DESTROY});
    }
  }
}

module.exports = { MultistackStack }

Python

File: multistack/multistack_stack.py


import aws_cdk as cdk
from constructs import Construct
from aws_cdk import aws_s3 as s3

class MultistackStack(cdk.Stack):

    # The Stack class doesn't know about our encrypt_bucket parameter,
    # so accept it separately and pass along any other keyword arguments.
    def __init__(self, scope: Construct, id: str, *, encrypt_bucket=False,
                 **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        # Add a Boolean property "encryptBucket" to the stack constructor.
        # If true, creates an encrypted bucket. Otherwise, the bucket is unencrypted.
        # Encrypted bucket uses KMS-managed keys (SSE-KMS).
        if encrypt_bucket:
            s3.Bucket(self, "MyGroovyBucket",
                      encryption=s3.BucketEncryption.KMS_MANAGED,
                      removal_policy=cdk.RemovalPolicy.DESTROY)
        else:
            s3.Bucket(self, "MyGroovyBucket",
                     removal_policy=cdk.RemovalPolicy.DESTROY)

Java

File: src/main/java/com/myorg/MultistackStack.java


package com.myorg;

import software.amazon.awscdk.Stack;
import software.amazon.awscdk.StackProps;
import software.constructs.Construct;
import software.amazon.awscdk.RemovalPolicy;

import software.amazon.awscdk.services.s3.Bucket;
import software.amazon.awscdk.services.s3.BucketEncryption;

public class MultistackStack extends Stack {
    // additional constructors to allow props and/or encryptBucket to be omitted
    public MultistackStack(final Construct scope, final String id,
            boolean encryptBucket) {
        this(scope, id, null, encryptBucket);
    }

    public MultistackStack(final Construct scope, final String id) {
        this(scope, id, null, false);
    }

    // main constructor
    public MultistackStack(final Construct scope, final String id,
            final StackProps props, final boolean encryptBucket) {
        super(scope, id, props);

        // Add a Boolean property "encryptBucket" to the stack constructor.
        // If true, creates an encrypted bucket. Otherwise, the bucket is
        // unencrypted. Encrypted bucket uses KMS-managed keys (SSE-KMS).
        if (encryptBucket) {
            Bucket.Builder.create(this, "MyGroovyBucket")
                    .encryption(BucketEncryption.KMS_MANAGED)
                    .removalPolicy(RemovalPolicy.DESTROY).build();
        } else {
            Bucket.Builder.create(this, "MyGroovyBucket")
                    .removalPolicy(RemovalPolicy.DESTROY).build();
        }
    }
}

C#

File: src/Multistack/MultistackStack.cs


using Amazon.CDK;
using Amazon.CDK.AWS.S3;

namespace Multistack
{
    
    public class MultiStackProps : StackProps
    {
        public bool? EncryptBucket { get; set; }
    }

    public class MultistackStack : Stack
    {
        public MultistackStack(Construct scope, string id, IMultiStackProps props = null) : base(scope, id, props)
        {
            // Add a Boolean property "EncryptBucket" to the stack constructor.
            // If true, creates an encrypted bucket. Otherwise, the bucket is unencrypted.
            // Encrypted bucket uses KMS-managed keys (SSE-KMS).
            if (props?.EncryptBucket ?? false)
            {
                new Bucket(this, "MyGroovyBucket", new BucketProps
                {
                    Encryption = BucketEncryption.KMS_MANAGED,
                    RemovalPolicy = RemovalPolicy.DESTROY
                });
            }
            else
            {
                new Bucket(this, "MyGroovyBucket", new BucketProps
                {
                    RemovalPolicy = RemovalPolicy.DESTROY
                });
            }
        }
    }
}

Create two stack instances

Now we'll add the code to instantiate two separate stacks. As before, the lines of code shown in bold are the ones you need to add. Delete the existing MultistackStack definition.

TypeScript

File: bin/multistack.ts


#!/usr/bin/env node
import 'source-map-support/register';
import * as cdk from 'aws-cdk-lib';
import { MultistackStack } from '../lib/multistack-stack';

const app = new cdk.App();

new MultistackStack(app, "MyWestCdkStack", {
    env: {region: "us-west-1"},
    encryptBucket: false
});
  
new MultistackStack(app, "MyEastCdkStack", {
    env: {region: "us-east-1"},
    encryptBucket: true
});
          
app.synth();

JavaScript

File: bin/multistack.js


#!/usr/bin/env node
const cdk = require('aws-cdk-lib');
const { MultistackStack } = require('../lib/multistack-stack');

const app = new cdk.App();

new MultistackStack(app, "MyWestCdkStack", {
    env: {region: "us-west-1"},
    encryptBucket: false
});
  
new MultistackStack(app, "MyEastCdkStack", {
    env: {region: "us-east-1"},
    encryptBucket: true
});
          
app.synth();

Python

File: ./app.py


#!/usr/bin/env python3

import aws_cdk as cdk

from multistack.multistack_stack import MultistackStack

app = cdk.App()
MultistackStack(app, "MyWestCdkStack",
                env=cdk.Environment(region="us-west-1"),
                encrypt_bucket=False)

MultistackStack(app, "MyEastCdkStack",
                env=cdk.Environment(region="us-east-1"),
                encrypt_bucket=True)
            
app.synth()

Java

File: src/main/java/com/myorg/MultistackApp.java


package com.myorg;

import software.amazon.awscdk.App;
import software.amazon.awscdk.Environment;
import software.amazon.awscdk.StackProps;

public class MultistackApp {
    public static void main(final String argv[]) {
        App app = new App();

        new MultistackStack(app, "MyWestCdkStack", StackProps.builder()
                .env(Environment.builder()
                        .region("us-west-1")
                        .build())
                .build(), false);

        new MultistackStack(app, "MyEastCdkStack", StackProps.builder()
                .env(Environment.builder()
                        .region("us-east-1")
                        .build())
                .build(), true);

        app.synth();
    }
}

C#

File: src/Multistack/Program.cs


using Amazon.CDK;

namespace Multistack
{
    class Program
    {
        static void Main(string[] args)
        {
            var app = new App();

            new MultistackStack(app, "MyWestCdkStack", new MultiStackProps
            {
                Env = new Environment { Region = "us-west-1" },
                EncryptBucket = false
            });

            new MultistackStack(app, "MyEastCdkStack", new MultiStackProps
            {
                Env = new Environment { Region = "us-east-1" },
                EncryptBucket = true
            });

            app.Synth();
        }
    }
}

This code uses the new encryptBucket (Python: encrypt_bucket) property on the MultistackStack class to instantiate the following:

One stack with an encrypted Amazon S3 bucket in the us-east-1 AWS Region.
One stack with an unencrypted Amazon S3 bucket in the us-west-1 AWS Region.

Synthesize and deploy the stack

Now you can deploy stacks from the app. First, synthesize an AWS CloudFormation template for MyEastCdkStack—the stack in us-east-1. This is the stack with the encrypted S3 bucket.


$ cdk synth MyEastCdkStack

To deploy this stack to your AWS account, issue one of the following commands. The first command uses your default AWS profile to obtain the credentials to deploy the stack. The second uses a profile that you specify. For PROFILE_NAME, substitute the name of an AWS CLI profile that contains appropriate credentials for deploying to the us-east-1 AWS Region.


cdk deploy MyEastCdkStack


cdk deploy MyEastCdkStack --profile=PROFILE_NAME

Clean up

To avoid charges for resources that you deployed, destroy the stack using the following command.


cdk destroy MyEastCdkStack

The destroy operation fails if there is anything stored in the stack's bucket. There shouldn't be if you've only followed the instructions in this topic. But if you did put something in the bucket, you must delete the bucket contents before destroying the stack. (Do not delete the bucket itself.) Use the AWS Management Console or the AWS CLI to delete the bucket contents.

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