Backend engineering task

Intro

The repository contains a bare setup for a REST API to place orders via a POST - /orders request, it can be found in ./app/api.py. Additionally, it contains a building block that symbolizes placing an order at the stock exchange.

The folder tests contains the setup for tests with the framework pytest.

The challenge in this repository is a simplified version of what we are dealing with at lemon.markets 🍋.

Your task

We would like you to finalize the missing parts in this repository so that the following requirements are fulfilled:

1. A valid request to POST /orders should result in the order being stored in a database of your choice.
2. The created order should be placed at the stock exchange (use the method place_order provided in stock_exchange.py).
3. The endpoint should return a status code of 201 and the created order details, provided that the order has been saved in the database AND it is guaranteed that the order will be placed on the stock exchange.
4. In the case of an error in the endpoint, it should return the status code 500 and the body {"message": "Internal server error while placing the order"}
5. The API should be highly scalable and reliable. The reliability of the provided stock exchange should not impact the reliability of the POST /orders endpoint

Additionally, please add some tests and document how you would test the application as a whole and its pieces. For the implementation you can choose to use this Python setup or implement it in Javascript/Typescript.

Please include a solution.md file where you document your decisions, assumptions, and also improvements you would like to incorporate in the future.

We value your time ⏰, so we do not expect you to spend more than 4 hours preparing the solution. 🤗 Focus on implementing the main task first and afterwards jump on additional improvements as you see fit.

Bonus tasks

• How would you change the system if we would receive a high volume of async updates to the orders placed through a socket connection on the stock exchange, e.g. execution information? Please outline the changes in the solution.md.
• Feel free to add a GitHub actions workflow to test the application.
• Feel free to add a Dockerfile.

Code quality

In order to maintain a certain amount of code quality, we are using pre-commit hooks in this repository, which are installed by a 3rd-party tool called pre-commit.

Please follow this documentation to install pre-commit on your local machine. After that just execute the following command to install the hooks to your git folder:

pre-commit install

Everything process related

Please create a fork or clone of this repository, commit all of your work to a new branch, and provide us with a link to the solution via mail 📩, at least 6h before the review meeting.