If you’re deploying your app on Fly.io, you can add Subtrace in just a couple of steps. Depending on the kind of Fly builder you’re using, the instructions are different.

We’ll use a Python Uvicorn server as an example, but you can do this with any language and framework.

Make the following changes to your app’s Dockerfile:

- CMD ["uvicorn", "main:app", "--host", "0.0.0.0"]
+ RUN curl -fsSLO "https://subtrace.dev/download/latest/$(uname -s)/$(uname -m)/subtrace" && chmod +x ./subtrace
+ CMD ["./subtrace", "run", "--", "uvicorn", "main:app", "--host", "0.0.0.0"]

You might also need to install curl and ca-certificates in your container since Fly.io runtimes may not include them by default.

Get a SUBTRACE_TOKEN from the Tokens page on the dashboard and set it as a Fly.io secret:

fly secrets set SUBTRACE_TOKEN=subt_...

Deploy your app as you normally would:

fly deploy

That’s it! You can now visit your app and make some requests to see them automatically appear in the Subtrace dashboard.