HTTP and UDP Server running on same port on Fly.io

We've written a Python file that runs a HTTP server and a UDP server both on the same port (8080).

For UDP server on fly.io, there are two important things to note:

1. We need to bind it to fly-global-services, NOT localhost. See line 50 in the main.py file.
2. We need to allocate a dedicated ipv4 address for the app.

Steps

1. I've created a fly.toml file in the root directory with the following content:

   [http_service]
   internal_port = 8080
   force_https = true
   auto_stop_machines = 'suspend'
   auto_start_machines = true
   min_machines_running = 1
   processes = ['app']
   
   [[services]]
   protocol = 'udp'
   internal_port = 8080
   
   [[services.ports]]
   port = 8080
   

2. Launch the app on Fly.io

   fly launch --org sahil-manocha-115
   

   Note: fly launch = Create a new app on Fly.io. Use fly deploy to update an existing app.

3. It will ask

   An existing fly.toml file was found
   ? Would you like to copy its configuration to the new app? (y/N)
   

   Type y and press enter.

4. It will ask for app's configuration (region, name, etc.). Then it will build the image & push it to the registry.

5. IMPORTANT: Then it will ask if we want to allocate a dedicated ipv4 address for the app. SAY YES.

   ? Would you like to allocate a dedicated ipv4 address now? Y
   

6. Once it's done, it will show the app's URL.

   Visit your newly deployed app at https://fly-http-and-udp.fly.dev/
   

7. Send HTTP requests to the app's URL.

   $ curl https://fly-http-and-udp.fly.dev/
   Hello from HTTP server!
   

8. Send UDP requests to the app's URL.

   $ echo "biraj rocks" | nc -u -w 1 fly-http-and-udp.fly.dev 8080
   Received UDP: biraj rocks
   

View logs

In the same directory as this app, run:

$ fly logs

Or you can view the logs on Grafana by going to the app's dashboard and clicking on Log search on the left.

How to ssh into the app

Make sure that a machine is running on fly.io.

$ fly ssh

Misc

• fly-global-services is a hostname in /etc/hosts file on the fly.io machine. You can check it by sshing into the machine.
• A dedicated ipv4 costs $2 per month.