self-hosting/modules/monitoring-exporters.nix

{ config, lib, ... }:
let cfg = config.custom.services.monitoring-exporters;
in {
  options.custom.services.monitoring-exporters = {
    enable = lib.mkEnableOption "monitoring-exporters";
  };

  config = lib.mkIf cfg.enable {
    services.prometheus = {
      exporters = {
        node = {
          enable = true;
          enabledCollectors = [ "systemd" "processes" ];
        };
      };
    };

    services.promtail = {
      enable = true;
      configuration = {
        server = {
          http_listen_port = 3101;
          grpc_listen_port = 0;
        };
        clients = [{ url = "http://10.0.2.3:3100/loki/api/v1/push"; }];
        scrape_configs = [
          {
            job_name = "journal";
            journal = {
              max_age = "12h";
              labels = {
                job = "systemd-journal";
                host = "${config.networking.hostName}";
              };
            };
            relabel_configs = [{
              source_labels = [ "__journal__systemd_unit" ];
              target_label = "unit";
            }];
          }
          (lib.mkIf config.services.nginx.enable {
            job_name = "nginx";
            static_configs = [{
              targets = [ "localhost" ];
              labels = {
                job = "nginx";
                host = "${config.networking.hostName}";
                __path__ = "/var/log/nginx/*.log";
              };
            }];
          })
        ];
      };
    };

    systemd.services.promtail.serviceConfig = {
      ReadOnlyPaths = lib.mkIf config.services.nginx.enable "/var/log/nginx";
      SupplementaryGroups = lib.mkIf config.services.nginx.enable [ "nginx" ];
    };
  };
}