prometheus.exporters.qbittorrent: init

[milahu]

fix NixOS#264637

example config, using nur.repos.milahu.prometheus-qbittorrent-exporter

/etc/nixos/configuration.nix

{
  # override nixos modules
  # https://stackoverflow.com/a/46407944/10440128
  disabledModules = [
    "services/monitoring/prometheus/exporters.nix"
  ];

  imports = [
    /home/user/src/nixpkgs/nixos/modules/services/monitoring/prometheus/exporters.nix
  ];

  # https://nixos.wiki/wiki/Grafana
  # nixpkgs/nixos/modules/services/monitoring/grafana.nix
  # https://xeiaso.net/blog/prometheus-grafana-loki-nixos-2020-11-20/
  # http://localhost:3000/
  # login: admin:admin
  services.grafana = {
    enable = true;
    declarativePlugins = with pkgs.grafanaPlugins; [
      grafana-piechart-panel # for prometheus-qbittorrent-exporter
    ];
  };

  # https://xeiaso.net/blog/prometheus-grafana-loki-nixos-2020-11-20/
  services.prometheus = {
    enable = true;
    port = 9001;
    # /var/lib/prometheus2/
    #retentionTime = "15d"; # default -> 80 MB
    retentionTime = "740d"; # 2 years -> 4 GB
    exporters = {
      node = {
        enable = true;
        enabledCollectors = [ "systemd" ];
        port = 9002;
      };
      qbittorrent = {
        enable = true;
        port = 9003;
        qbittorrentPort = 1952;
        package = pkgs.nur.repos.milahu.prometheus-qbittorrent-exporter;
      };
    };
    scrapeConfigs = [
      {
        job_name = "chrysalis";
        static_configs = [{
          targets = [
            "127.0.0.1:${toString config.services.prometheus.exporters.node.port}"
            "127.0.0.1:${toString config.services.prometheus.exporters.qbittorrent.port}"
          ];
        }];
      }
    ];
  };
}

ping @riley-martine

feel free to create a PR for https://github.com/NixOS/nixpkgs
i am banned for "hatespeech"