C++ Telemetry Poller

git View Source
Tags
#telemetry #conky #custom engine #tech writing

From Bash Hacks to System Monitoring

The Problem: Silent Disk Failures

It started with a simple, silent failure. My Raspberry Pi server ran out of disk space, and I had no idea. I wasn't monitoring it, and while I could have just SSH’d in and ran df -h or top every hour, that's not how an engineer solves a problem.

At the time, my go-to for desktop metrics was Conky. I had a basic Bash script that would use an SSH command to poll the Pi, and Conky would display that on my laptop. It worked, but it felt fragile.

The Pivot: Learning C++ Through Necessity

I was about to start a C++ class in college and wanted to get ahead of the curve. Reading a file in C++ and printing it to the console seemed like a "level one" task, so I decided to rebuild my monitoring tool from scratch.

What started as a disk monitor soon became my preferred tool. It was faster and more consistent than my old scripts. Soon, I was using the same C++ logic to generate Conky strings for both my laptop and my server. It was stable, it was mine, and it helped me ace that semester.

The Wayland Roadblock

Then came the migration to Wayland. Conky is a staple of the Xorg world, but running it in Wayland usually requires "backdoors" like XWayland. I didn't see the point in moving to a modern display protocol if I was just going to keep Xorg dragging along in the background for a clock and a disk meter.

I needed a change. By this point, the core C++ telemetry engine was solid, but I needed it to speak a different language. I shifted the output from Conky strings to JSON so it could be consumed by Eww (ElKowar's Wacky Widgets) using Yuck.

The Network "Cheat Code"

The final challenge was remote monitoring. I considered writing a full-blown socket server in C++, but honestly? I wanted it to work now.

I spun up a functional Python server in about five minutes. It takes the JSON output from my C++ poller and broadcasts it over my local network. Now, my Eww widgets can remotely monitor the Raspberry Pi from any machine in the house.

"It took me nearly the entire semester to finish the C++ logic, but only five minutes to serve it over the network. It felt like I was cheating, but it worked."

Implementation Notes

  • Source Code: The core telemetry poller is available in the repo.
  • Environment: Built for NixOS and Debian, but should run anywhere with a C++ compiler.
  • The "Glue": I haven't included the Python server or the specific Eww/Yuck configs here (they live in a seperate repo), but if you're comfortable with networking and widgets, you can probably see how the pieces fit together.