How to deploy FastAPI with Nginx and Supervisor

In this tutorial, I will show you how to deploy a FastAPI app with Nginx and Supervisor.

First, launch a compute instance with a cloud platform of your choice. I will be using Ubuntu version 20.04 along with the default python version 3.8 and default ubuntu user.

Update packages.

sudo apt-get update

Install pip, venv, and nginx.

sudo apt-get -y install python3-pip python3-venv nginx supervisor

If you go to your IP address, you should see the welcome to nginx page.

Create a directory for the app.

mkdir hello_world
cd hello_world

Create and activate the virtualenv.

python3 -m venv venv
. venv/bin/activate

Install fastapi, uvicorn, and gunicorn.

pip install fastapi "uvicorn[standard]" gunicorn

Create the main.py file.

nano main.py

Paste the following code and save the file.

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"Hello": "World"}

Create the supervisord.conf file in /etc/supervisor/conf.d/

cd /etc/supervisor/conf.d
sudo nano supervisord.conf

Paste the following in supervisord.conf.

[inet_http_server]
port=127.0.0.1:9001

[rpcinterface:supervisor]
supervisor.rpcinterface_factory = supervisor.rpcinterface:make_main_rpcinterface

[supervisorctl]
serverurl=http://127.0.0.1:9001

[supervisord]

[program:hello_world]
environment = PYTHONUNBUFFERED=1
user=ubuntu
directory=/home/ubuntu/hello_world/
command=/home/ubuntu/hello_world/venv/bin/gunicorn -w 4 -k uvicorn.workers.UvicornWorker main:app
autostart=true
autorestart=true
stderr_logfile=/var/log/hello_world/hello_world.err.log
stdout_logfile=/var/log/hello_world/hello_world.out.log

Note: Since Python output is buffered, the PYTHONUNBUFFERED=1 allows us to see output in our logs immediately.

Create the log folder and change the owner.

sudo mkdir /var/log/hello_world
sudo chown -R ubuntu:ubuntu /var/log/hello_world

Start supervisord.

sudo supervisord -c /etc/supervisor/conf.d/supervisord.conf

Verify that fastapi is running.

curl localhost:8000

Configure nginx.

cd /etc/nginx/conf.d/
sudo nano default.conf

Create a default.conf. Make sure to replace the IP address.

server {
  listen 80;

  server_name 123.456.789.10 example.com;

  location / {
    proxy_pass http://localhost:8000;
  }
}

Restart nginx.

sudo service nginx restart

Go to the IP in your browser. You should see hello world.

Other useful commands:

sudo supervisorctl
sudo supervisorctl status
sudo supervisorctl stop all
sudo supervisorctl start all
sudo supervisorctl reload
sudo supervisorctl restart
sudo supervisorctl tail -f hello_world
sudo supervisorctl tail -f hello_world stderr
sudo service supervisor stop
sudo service supervisor start