I opted in to provide data to flightradar24 which has several benefits, the best of which is that I get a Business subscription for free. The stuff runs on a software-defined radio receiver connected to a Raspberry Pi.

Unfortunately — unknown to me as to why — the software can become flaky and disconnect without notifying me. So I made it my mission to have some sort of monitoring.

There’s a command — fr24feed-status — that reports on what’s going on. An example output looks like this:

sesam in 🌐 bringebaer in ~ via 🐍 v3.9.2
❯ fr24feed-status
  FR24 Feeder/Decoder Process: running.
  FR24 Stats Timestamp: 2023-01-20 16:30:21.
  FR24 Link: connected [UDP].
  FR24 Radar: T-ESSB413.
  FR24 Tracked AC: 3.
  Receiver: connected (367616 MSGS/0 SYNC).
  FR24 MLAT: ok [UDP].
  FR24 MLAT AC seen: 1.

Whenever any of the responses contains “Failed” something went awry, that’s when I wanted a notification. Problem #1, I don’t speak bash. Enter ChatGPT, and the question: write a bash script that runs fr24feed-status and if the result contains Failed then email X.

It’s actually not that hard, could have learned myself…

sesam in 🌐 bringebaer in ~ via 🐍 v3.9.2
❯ cat fr24feed-alert.sh
  #!/bin/bash

  # Run fr24feed-status and save the output
  status=$(fr24feed-status)

  # Check if the output contains "Failed"
  if [[ $status == *"Failed"* ]]
  then
  # Send an email to petersz@me.com
  echo "$status" | mailx -s "fr24feed Status Failed" petersz@me.com
  fi

The most complex bit was to make sure that the Raspberry can send actual emails. Mailx is your friend. You need an application password and a configuration file to succeed.

So far it’s been stable so needs testing. 😅