Shopping Cart Service

Sample shopping cart CRUD service using Python3/FastAPI and Kubernetes

Getting Started

To get started make sure the following requirements (for development and deployment tooling) are installed on your development machine:

• GNU Make (Script Runner)
• Python 3.10 (Project Programming Language)
• Virtualenv (Python Dependency Manager)
• DBMate (Platform-agnostic Database Migrations Tool)
• Docker (Containerization)
• Kubectl (K8s deployment CLI)
• cURL (HTTP REST client)

Background

The goal of this project is to demonstrate what managing, testing, building and deploying a CRUD Python service looks like. By building this service, I was able see how the following works: - building an API service using fastapi - setting up integration tests via pytest - applying type safety (Protocol, Generic, TypeVar) to Python via the typing library and mypy - using the Result library - setting up Postgres via Kubernetes - setting up Database migrations via DBMate

Also, this project uses the make command quite frequently. Similar to how gradle is used in Java, Spring, or many other JVM-based projects, make is used as a tool that acts as an "interface" to the project. A big reason as to why I've chosen make as my de-facto "project interface tool" is that it acts as a simple, well documented, script runner and it's generally available on most unix-based machines. For more info on the available make commands, check out the usage section.

Playing with the Shopping Cart Service

To get the health endpoint, run the following command:

curl -X GET localhost:5001/health

To get all cart items, run the following command:

curl -X GET 'localhost:5001/cart?page_number=0&page_size=20'

To get a cart item by id, run the following command:

curl -X GET localhost:5001/cart/1

To add a cart item, run the following command:

curl \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"name":"70-200mm Lens","price":240000,"manufacturer": "Canon"}' \
    localhost:5001/cart/

To update a cart item, run the following command:

curl \
    -X PUT \
    -H "Content-Type: application/json" \
    -d '{"name": "Lens Cap", "price": "888888888", "manufacturer": "Canon"}' \
    localhost:5001/cart/1

To remove a cart item, run the following command:

curl -X DELETE localhost:5001/cart/1

Development

First, make sure that the project dependencies have been installed with the following command:

make install

Next, let's make sure the test suite for the application is running as expected.

1. Check to make sure Docker is running.

2. Since our test suite talks to a database, let's make sure that PostgreSQL is running locally via:

make start_local_db

3. Finally, let's run our tests via:

make test

If the test suite is not passing, please provide an issue for the project.

Usage

To install project dependencies, run the following command:

make install

To run all tests (make sure database is running), run the following command:

make test

To make sure the database is running, run the following command:

make start_local_db

To start the app and database locally, run the following command:

make start

To debug the local database, run the following command:

make debug_local_db

To build the docker image, run the following command:

make build_image

To debug the docker image, run the following command:

make debug_image

To push the docker image, run the following command:

make push_image

To deploy the shopping-cart-service, run the following command:

make deploy

To get the project in a clean state, run the following command:

make clean

License