feat: add OpentelemetryTesla.setup/1

[bryannaegele]

What's the context here? I don't see any docs or tests, and this seems to create a different way to instrument than middleware.

[yordis]

I don't see any docs or tests,

My bad, I am still working on it.

and this creates a different way to instrument than middleware.

It is precisely built on top of the :telemetry instead of adding the middleware.

As of today, https://hexdocs.pm/tesla/Tesla.Middleware.Telemetry.html is the way to add telemetry to Tesla instead of adding OTEL-specific middleware.

That will be in line with the rest of the instrumentation.

• What does that mean for Tesla.Middleware.OpenTelemetry moving forward?

It Depends ™️

Tesla.Middleware.OpenTelemetry would be only needed when you want to :propagator, not for "telemetry." I am still unsure what that means in practice for the time being. But they can both live together for the time being.

[bryannaegele]

I believe there were a number of issues around where that middleware is defined and what it contained. Those events have been around for many years. I think it might have included an issue with path params not being processed before telemetry fired.

One issue is this creates a single processor which will process requests from all clients using Tesla. I think in the case of Req, this would create multiple traces/spans if the user has Tesla as the backend and some library uses Tesla directly. That could possibly be addressed in docs but something that you'll need to test.

I don't see a world where this replaces the middleware which provides finer-grained control per client implementation.

[yordis]

I don't see a world where this replaces the middleware which provides finer-grained control per client implementation.

Yeah ... that is OK.

So what should the resolution be from your perspective about the topic?