self-hosting/modules/monitoring-exporters.nix

{ config, lib, ... }:
{
  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" ];
  };
}