creating lambda with CDK typescript and LocalStack
preface
Creating an AWS Lambda function with AWS CDK (Cloud Development Kit) using TypeScript and testing it locally with LocalStack can streamline your development process. First, you need to set up your CDK project by installing the necessary dependencies, such as aws-cdk and @aws-cdk/aws-lambda. Once your environment is ready, you define your Lambda function within the CDK stack, specifying the runtime, handler, and the code source. The code for your Lambda is typically placed in a separate directory, and you can write it in JavaScript or TypeScript.
With LocalStack, you can simulate AWS services locally. You integrate LocalStack with your CDK project by pointing your AWS CLI and SDKs to LocalStack’s endpoints. This setup allows you to deploy and test your Lambda functions locally, mimicking the AWS environment without incurring costs or delays associated with deploying to the cloud. This approach enhances your development workflow by enabling rapid iteration and testing before the final deployment to AWS. By combining CDK, TypeScript, and LocalStack, you can efficiently manage your infrastructure as code and ensure your serverless applications are robust and ready for production.
The entire codebase is available here.
steps
Given the power and complexity of LocalStack, I’ll keep things straightforward. I’m using the pro version (with a 14-day trial) because it provides a user-friendly interface for my convenience. To follow along, please create an account to replicate my steps. Prerequisites
- Docker
- node.js and npm installed locally
Steps
- Clone the repository.
- Follow the instructions in the README.
Below, I’ll illustrate the steps through screenshots to guide you.
Usage
- Clone the repository
git clone https://github.com/matsonkepson/cdk-stuff
- Install the code dependencies
cd cdk-stuff
npm install
- Install dependencies for LocalStack
# Install globally
npm install -g aws-cdk-local aws-cdk
# Verify it installed correctly
cdklocal --version
# e.g. 2.171.1 (build a95560c)
- Run LocalStack
Inside the repo there is a docker-compose file ready to fly. Make sure you exported the auth token prior to running docker compose!
export LOCALSTACK_AUTH_TOKEN="yourSecretTokenFromLocalstack"
docker-compose -f localstack/docker-compose.yml up
After the container is ready to go you can check it directly from the web page where you have created your account https://app.localstack.cloud/inst/default/overview
Bootstrap to activate CloudFormation Api
If this step fails at the first time please stop the localstack container and remove the localstack/volume folder with sudo permissions from the cloned repo!
cdklocal bootstarp
- Deploy your changes to LocalStack
cdklocal deploy
- Update your config and check the drift
cdklocal diff
Check the results
Search the Lambda resource
Invoke the Lambda and see your results
