Recursion Tree Visualizer

🥇 Winner project of the AlgoExpert SWE Project Contest 🥇

Overview

Stop drawing recursion trees by hand. Watch the demo video or check out the live project.

Folders structure

• packages/web: react user interface.
• packages/lambda: serverless lambda function to execute user-defined code remotely.

Local development

Web

In the packages/web directory, run:

# to install all dependencies
$ npm install

# to run the app on http://localhost:3000
$ npm run start

Lambda

You can use the Amazon Runtime Interface Emulator (RIE), already contained in the docker image, to test the Lambda function.

In the packages/lambda directory, run:

# build your local image
$ docker build --tag rtv .

# create and run a container using AWS RIE as executable to emulate a server for your lambda function
$ docker run --rm -p 8080:8080 rtv

# make a http request to your function, passing event with the -d in body field (escaped json), see examples in requests.http file
$ curl -XPOST "http://localhost:8080/2015-03-31/functions/function/invocations" -d '{"body":"{}"}'

Deploy to production

Web

Set your API Gateway endpoint in packages/web/src/config/api.ts.

Ships packages/web on Vercel.

Lambda

The deployment of the Lambda function is automatized by the workflow cd-lambda-function. You will need to complete the following set-up steps to use it:

1. Create the following AWS resources:

   • Lambda function defined as a container image

   • API Gateway to trigger the lambda function with CORS support

   • ECR repository to store your Docker images

   • IAM user with the proper permissions

2. Store the IAM user access key in GitHub Actions secrets named AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.

3. Change the workflow file github/workflows/cd-lambda-function.yml:

   • Replace the value of the AWS_REGION env with the region of all your AWS resources.

   • Replace the value of the AWS_ECR_REPOSITORY_NAME env with your repository's name.

   • Replace the value of the AWS_LAMBDA_FUNCTION_NAME env with your function's name.

Acknowledgements

Thanks to Drawing Presentable Trees and Improving Walker's Algorithm to Run in Linear Time articles I implemented Reingold-Tilford's algorithm to position each node of the tree on a 2D plane in an aesthetically pleasing way.

Compatibility

For a better experience, I recommend using a chromium-based browser like Chrome or Edge.

Contact me

• Twitter