FastAPI Redis Example

This is an example API that demonstrates how to use Redis with FastAPI to build a fully async web service in Python.

The API is called IsBitcoinLit. Readers outside the U.S. who are unfamiliar with the slang term "lit" might enjoy this Merriam-Webster etymology.

The IsBitcoinLit API tracks Bitcoin sentiment and prices over time, rolling these up into hourly averages of averages using the RedisTimeSeries module. You can use the API to get average Bitcoin price and sentiment for each of the last three hours, with a quick indication of price and sentiment movement.

Setup

This project is designed to run as a set of Docker containers. You will need to install Docker to complete the setup tasks.

First, clone this repo and build the Docker images for the project:

$ git clone https://github.com/redis-developer/fastapi-redis-tutorial.git
$ cd fastapi-redis-tutorial
$ docker-compose build

Running the API involves starting the app server and Redis. You'll do those steps next!

Running the API

The docker-compose.yaml file in this project configures containers for a Redis instance with the RedisTimeSeries module, the Python app for the example API, and a test runner.

Use this command to run all three containers:

$ docker-compose up

This command starts Redis and the API server and runs the tests.

Ingesting Price and Sentiment Data

A /refresh endpoint exists in the app that ingests the last 24 hours of Bitcoin price and sentiment data.

The app assumes a scheduler (cron job, Google Cloud Scheduler, etc.) will hit the /refresh endpoint on a regular basis to keep data fresh.

NOTE : We can refresh data as often as we want without getting duplicate data. This is because RedisTimeSeries allows configuring rules to ignore duplicate sample and timestamp pairs.

After you first start the API, use the /refresh API to ingest data:

$ curl -X POST localhost:8080/refresh

Now you can use the /is-bitcoin-lit endpoint to see a summary of Bitcoin price and sentiment data. Continue reading to see how to use that endpoint.

NOTE: We've used the free SentiCrypt API to pull Bitcoin sentiment and price. We are not affiliated with SentiCrypt and this is in no way a recommendation to use the API for crypto price and sentiment tracking in real applications.

Getting Summary Price and Sentiment Data from the API

Use the /is-bitcoin-lit endpoint to get an hourly summary of Bitcoin price and sentiment data for the last three hours:

$ curl localhost:8080/is-bitcoin-lit | jq

    {
    "hourly_average_of_averages": [
        {
        "price": "32928.345",
        "sentiment": "0.22",
        "time": "2021-07-08T17:00:00+00:00"
        },
        {
        "price": "32834.2910891089",
        "sentiment": "0.224257425742574",
        "time": "2021-07-08T18:00:00+00:00"
        },
        {
        "price": "32871.3406666667",
        "sentiment": "0.208666666666667",
        "time": "2021-07-08T19:00:00+00:00"
        }
    ],
    "sentiment_direction": "rising",
    "price_direction": "rising"
    }

As you can see, the response includes the key hourly_average_of_averages. This key contains hourly averages derived from the Bitcoin sentiment API's data, which is itself averaged over 30-second periods. (Thus, these are averages of averages.)

The API also returns the direction that the price and sentiment are moving. The directions are:

Value	Meaning
Rising	The price has risen over the past three hours.
Falling	The price has fallen over the past three hours.
Neutral	The price stayed the same for three hours (unlikely!)

So, is Bitcoin lit in this example? Yes, it's lit: the price and sentiment are rising. See how that works?

Running Tests

You can run the app's test suite using docker-compose:

$ docker-compose up test