# Grafana Alloy: ships the full systemd journal to Loki.
# The nixpkgs module reads /etc/alloy/*.alloy and already runs with the
# systemd-journal supplementary group. Alloy exposes /metrics + UI on :12345.
{
  config,
  lib,
  ...
}:
let
  cfg = config.my.profiles.monitoring;
in
{
  config = lib.mkIf cfg.enable {
    services.alloy.enable = true;

    environment.etc."alloy/config.alloy".text = ''
      loki.source.journal "journal" {
        max_age       = "24h"
        forward_to    = [loki.write.local.receiver]
        relabel_rules = loki.relabel.journal.rules
        labels        = { host = "jupiter" }
      }

      loki.relabel "journal" {
        forward_to = []
        rule {
          source_labels = ["__journal__systemd_unit"]
          target_label  = "unit"
        }
        rule {
          source_labels = ["__journal_priority_keyword"]
          target_label  = "priority"
        }
        rule {
          source_labels = ["__journal__transport"]
          target_label  = "transport"
        }
        rule {
          source_labels = ["__journal__boot_id"]
          target_label  = "boot_id"
        }
      }

      loki.write "local" {
        endpoint {
          url = "http://127.0.0.1:3100/loki/api/v1/push"
        }
      }
    '';
  };
}