fastapi-faust-example

A quick POC for integrating FastAPI and Faust.

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

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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.

Running the app locally

• 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.