radiobert: add dump1090, feed to collectd for grafana

hosts/radiobert/collectd-adsb.rb

@@ -0,0 +1,27 @@
+#!/usr/bin/env ruby
+
+require 'open-uri'
+require 'json'
+require 'distance'
+
+HOSTNAME = IO::readlines("/proc/sys/kernel/hostname").join.chomp
+INTERVAL = 10
+POS = [ 51.08102, 13.72806 ]
+
+loop do
+  planes = JSON.parse URI.open("http://localhost:8080/data.json").read
+
+  planes.each do |plane|
+    flight = plane["flight"].strip
+    next if flight.empty?
+
+    alt = plane["altitude"].to_i
+    speed = plane["speed"].to_i
+    dist = GIS::Distance::new(POS[0], POS[1], plane["lat"].to_f, plane["lon"].to_f).distance
+    puts "PUTVAL \"#{HOSTNAME}/dump1090-altitude/current-#{flight}\" interval=#{INTERVAL} N:#{alt}"
+    puts "PUTVAL \"#{HOSTNAME}/dump1090-speed/current-#{flight}\" interval=#{INTERVAL} N:#{speed}"
+    puts "PUTVAL \"#{HOSTNAME}/dump1090-distance/current-#{flight}\" interval=#{INTERVAL} N:#{dist}"
+  end
+
+  sleep INTERVAL
+end

hosts/radiobert/default.nix

@@ -137,8 +137,45 @@ in
           Type "gauge"
         </Key>
       </URL>
-    '';
+  users.users.dump1090 = {
+    isSystemUser = true;
+    group = "dump10190";
   };
+  users.groups.dump1090 = {};
+  systemd.tmpfiles.rules = [
+    "d /tmp/dump1090 0755 dump1090 dump1090 -"
+  ];
+  systemd.services.dump1090 = {
+    wantedBy = [ "multi-user.target" ];
+    serviceConfig = {
+      ExecStart = "${pkgs.dump1090_sdrplus}/bin/dump1090 --aggressive --net";
+      User = "dump1090";
+      Group = "dump1090";
+      ProtectSystem = "full";
+      ProtectHome = true;
+      WorkingDirectory = "/tmp/dump1090";
+      WritablePaths = "/tmp/dump1090";
+    };
+  };
+
+
+  # TODO: `services.collectd.plugins.exec` is already defined by pi-sensors
+  # (https://github.com/NixOS/nixpkgs/pull/141551)
+  services.collectd.extraConfig =
+    let
+      distanceRb = pkgs.fetchurl {
+        url = "https://github.com/djberg96/gis-distance/raw/main/lib/gis/distance.rb";
+        sha256 = "1m9zzikcl5pzad66r8vnlj2p2hbbcqb8vdcf34nrhyd4mg1wkgkh";
+      };
+      libDir = pkgs.runCommandNoCC "libdir" {} ''
+        mkdir $out
+        cp ${distanceRb} $out/distance.rb
+      '';
+    in ''
+      <Plugin exec>
+        Exec "${config.services.collectd.user}" "${pkgs.ruby}/bin/ruby" "-I${libDir}" "${./collectd-adsb.rb}"
+      </Plugin>
+    '';
 
   environment.systemPackages = with pkgs; [
     libraspberrypi