Feature request: A way to change the PID setpoints

[mjohnson9]

Is your feature request related to a problem? Please describe.
I'm trying to tune the PID, but I've run into the problem that the only way to change the setpoint is to stop and start the service, which resets the PID state. An important part of PID tuning is altering the setpoint while keeping the state, to see how the PID responds.

Describe the solution you'd like
A very simple way to allow changing the setpoint would be to reload the config when SIGHUP is received.

Describe alternatives you've considered
An API to change PID setpoints. This would be more complicated, and the extra complexity would likely be unnecessary.

[markusressel]

Hey @mjohnson9 👋

A very simple way to allow changing the setpoint would be to reload the config when SIGHUP is received.

Well I guess it depends on what your definition of simple is, as the only way to propagate a new config to the hole application would be to reinitialize it using that new config. That is certainly possible, but the code is not exactly setup for that, and "hot-reloading" is something I have never done before in any project.

An API to change PID setpoints. This would be more complicated, and the extra complexity would likely be unnecessary.

The API is currently read-only, and that is partly intentional. Opening up the API to support write operations leads to conflicts with the definitions within the configuration yaml, which is something I would like to avoid if possible.

I like the idea of a hot-reload feature in fan2go, but I don't even know where to start on this, and time is a very limited resource these days. If you feel like playing around with the codebase, feel free to create a draft PR if you get something.