localstack/aws-cdk-local

AWS Cloud Development Kit (CDK) for LocalStack

This project provides a thin wrapper script cdklocal for using the AWS CDK library against local APIs provided by LocalStack.

Note: This project replaces the old (deprecated) repo which was a fork of the AWS CDK repo. Instead of forking the repo and applying changes, we now simply provide a simple wrapper script cdklocal which applies runtime patching. The advantage of the new approach is that you should be able to use arbitrary CDK versions under the cover.

Quick Installation

The cdklocal command line is published as an npm library:

$ npm install -g aws-cdk-local aws-cdk
...
$ cdklocal --version
1.65.5

Note: Starting with version 1.65.2, the dependency aws-cdk needs to be installed manually (to decouple the two libraries, and allow using arbitrary versions of aws-cdk under the covers).

(Note: Depending on your local setup, you may or may not have to use the global npm installation flag -g above.)

Mac OS specific MODULE_NOT_FOUND issue

On Mac OS, brew can be used to install AWS CDK, which might result in a MODULE_NOT_FOUND error from cdklocal. To resolve this, set the NODE_PATH variable pointing to your AWS CDK's node_module folder to expand the lookup path for modules.

$ export NODE_PATH=$NODE_PATH:/opt/homebrew/Cellar/aws-cdk/<CDK_VERSION>/libexec/lib/node_modules

Version support

cdklocal supports all installed versions of the node aws-cdk package, however some complications are present for aws-cdk >= 2.177.0.

For these CDK versions, we remove AWS configuration environment variables like AWS_PROFILE from the shell environment before invoking the cdk command, and explicitly set AWS_ENDPOINT_URL and AWS_ENDPOINT_URL_S3 to target LocalStack.

1. We do this because other environment variables may lead to a conflicting set of configuration options, where the wrong region is used to target LocalStack, or cdklocal tries to deploy into upstream AWS by mistake. If individual configuration variables are needed for the deploy process (e.g. AWS_REGION) these configuration variables can be propagated to the cdk command by configuring AWS_ENVAR_ALLOWLIST, for example: AWS_ENVAR_ALLOWLIST=AWS_REGION,AWS_DEFAULT_REGION AWS_DEFAULT_REGION=eu-central-1 AWS_REGION=eu-central-1 cdklocal ....
2. If you are manually setting AWS_ENDPOINT_URL, the new value will continue to be read from the environment, however AWS_ENDPOINT_URL_S3 must also be set and should include a .s3. component to ensure we correctly detect S3 requests.

Configurations

The following environment variables can be configured:

• AWS_ENDPOINT_URL: The endpoint URL to connect to (combination of USE_SSL/LOCALSTACK_HOSTNAME/EDGE_PORT below)
• AWS_ENDPOINT_URL_S3: The endpoint URL to connect to (combination of USE_SSL/LOCALSTACK_HOSTNAME/EDGE_PORT below) for S3 requests
• AWS_ENVAR_ALLOWLIST: Allow specific AWS_* environment variables to be used by the CDK
• AWS_S3_FORCE_PATH_STYLE: Force path-style S3 URLs (CDK >= 2.177.0 only). Automatically enabled when AWS_ENDPOINT_URL hostname contains .sandbox.. See Path-style S3 URLs.
• EDGE_PORT (deprecated): Port under which LocalStack edge service is accessible (default: 4566)
• LOCALSTACK_HOSTNAME (deprecated): Target host under which LocalStack edge service is accessible (default: localhost)
• USE_SSL (deprecated): Whether to use SSL to connect to the LocalStack endpoint, i.e., connect via HTTPS.
• LAMBDA_MOUNT_CODE: Whether to use local Lambda code mounting (via setting __local__ S3 bucket name). Note: may require CDK version <2.14.0 to be fully functional.
• BUCKET_MARKER_LOCAL: Magic S3 bucket name for Lambda mount and hot reloading (default: __local__, will default to hot-reload in a future release)

Path-style S3 URLs for remote endpoints

When deploying with CDK >= 2.177.0 against endpoints whose hostname contains .sandbox. (e.g. *.sandbox.localstack.cloud), asset uploads to S3 require path-style URLs. The wildcard TLS certificate for these endpoints only covers one subdomain level and cannot match virtual-hosted-style bucket addresses like <bucket>.abc.sandbox.localstack.cloud.

cdklocal automatically enables path-style S3 when it detects a .sandbox. hostname in AWS_ENDPOINT_URL. You can also opt in explicitly via AWS_S3_FORCE_PATH_STYLE=1.

Deploying a Sample App

The CDK command line ships with a sample app generator to run a quick test for getting started:

$ mkdir /tmp/test; cd /tmp/test
$ cdklocal init sample-app --language=javascript
...

Make sure that LocalStack is installed and started:

$ localstack start

Then deploy the sample app against the local APIs via the cdklocal command line:

$ cdklocal deploy
...
Do you wish to deploy these changes (y/n)? y
...
Stack ARN:
arn:aws:cloudformation:us-east-1:000000000000:stack/TestStack/e3debc0a-311e-4968-8230-ed78f89cb614

Once the deployment is done, you can inspect the created resources via the awslocal command line:

$ awslocal sns list-topics
{
    "Topics": [
        {
            "TopicArn": "arn:aws:sns:us-east-1:000000000000:TestStack-TestTopic339EC197-79F43WWCCS4Z"
        }
    ]
}

Change Log

• 3.0.4: Fix asset publishing failures for CDK >= 2.177.0 against remote LocalStack endpoints (e.g. *.sandbox.localstack.cloud)
• 3.0.3: Add missing semver dependency
• 3.0.2: Add support for aws-cdk versions after 2026-03-01 (see https://github.com/aws/aws-cdk-cli/issues/310)
• 3.0.1: Using the -v/--version flag prints the cdklocal version and the version of the underlying aws-cdk package (if possible)
• 3.0.0: Sanitise environment of configuration environment variables before deployment
• 2.19.2: Fix SDK compatibility with aws-cdk versions >= 2.177.0
• 2.19.1: Fix SDK compatibility with older CDK versions; Fix patched bucket location in TemplateURL
• 2.19.0: Add support for aws-cdk versions >= 2.167.0
• 2.18.1: Throw better exception if aws-cdk not found
• 2.18.0: Add support for AWS_ENDPOINT_URL, USE_SSL, and BUCKET_MARKER_LOCAL configurations
• 2.17.0: Fix IPv4 fallback check to prevent IPv6 connection issue with localhost on macOS
• 2.16.0: Add check to prevent IPv6 connection issue with localhost on MacOS
• 2.15.0: Fix issue with undefined BUCKET_NAME_OUTPUT variable; add CI build and eslint config
• 2.14.0: Add switches in patches to accommodate new esbuild packaging mechanism in CDK v2.14.0+
• 1.65.7: Add switch that checks for asset existence before symlinking assets; fix parsing fetched template body for JSON/YAML formats; add missing dependency to "diff" package
• 1.65.6: Create symlinks to Lambda assets to enable persistent code mounting of Lambdas on "cdklocal synth"
• 1.65.5: Add support for LAMBDA_MOUNT_CODE config to enable local Lambda code mounting
• 1.65.4: Add support for large stacks by patching bucketUrl for ToolkitInfo
• 1.65.2: Patch missing getPromise() in forceCredentialRetrieval; remove aws-cdk from npm dependencies
• 1.65.1: Override BucketURL to use path style addressing
• 1.65.0: Initial release

License

The AWS CDK is distributed under the Apache License, Version 2.0.