fastapi-faust-example

A quick POC for integrating FastAPI and Faust.

This project implements a simple incrementer web app. See the .gif file below.

Basic Architecture

We use Docker Compose to set up 4 containers:
- api
- worker
- kafka
- zookeeper
The worker container is based on a custom docker image that has both Python and RocksDB installed already. To see how RocksDB is used in Faust, see here.
In the worker container, we define a GlobalTable to hold the current count for the incrementer.
Both the worker and api containers each have their own Faust app instance. However, the api Faust instance is started in "client-only" mode (i.e. just a producer and simple reply consumer).
When the user visits the webpage in their browser, the following happens:
- The browser makes a GET request to the API.
- The API asks a Faust agent to retrieve the current incrementer count value.
- Once the API gets this value, it responds to the browser with HTML that includes the current count.
When the user clicks the Increment button in their browser, the following happens:
- A POST request is sent to the API.
- The API then asks a Faust agent to increment the count value.
- Once the value is incremented, the API responds to the browser with a "redirect" response.
- The browser then redirects back to the original page, which displays the updated count value.

Install Docker on your machine.
git clone this repo.
cd into this repo, and run docker-compose up --build.
Open your web browser, and visit http://localhost:8000/
To stop running the app, go into the terminal, and press Ctrl + C. Then, run docker-compose down.