depot/cluster/services/monitoring/client.nix

{ cluster, config, lib, ... }:
let
  inherit (lib) singleton;

  relabel = from: to: {
    source_labels = [ from ];
    target_label = to;
  };
in {
  services.journald.extraConfig = "Storage=volatile";

  services.grafana-agent = {
    enable = true;
    settings = {
      metrics.global.remote_write = singleton {
        url = "${cluster.config.links.prometheus-ingest.url}/api/v1/write";
      };
      integrations.node_exporter = {
        enabled = true;
        instance = config.networking.hostName;
        enable_collectors = [
          "systemd"
        ];
      };
      logs.configs = singleton {
        name = "logging";
        positions.filename = "\${STATE_DIRECTORY:/tmp}/logging-positions.yaml";
        clients = singleton {
          url = "${cluster.config.links.loki-ingest.url}/loki/api/v1/push";
        };
        scrape_configs = singleton {
          job_name = "journal";
          journal = {
            max_age = "12h";
            labels.host = config.networking.hostName;
          };
          relabel_configs = [
            (relabel "__journal__systemd_unit" "systemd_unit")
            (relabel "__journal__hostname" "machine_name")
            (relabel "__journal__exe" "executable")
            (relabel "__journal__comm" "command")
            (relabel "__journal__boot_id" "systemd_boot_id")
            (relabel "__journal__systemd_cgroup" "systemd_cgroup")
            (relabel "__journal_syslog_identifier" "syslog_identifier")
          ];
        };
      };
    };
  };
}