grafana: re-organize

services/grafana/jellyfin-collector.nix

@@ -0,0 +1,54 @@
+{
+  config,
+  pkgs,
+  service_configs,
+  lib,
+  ...
+}:
+let
+  textfileDir = "/var/lib/prometheus-node-exporter-textfiles";
+
+  jellyfinCollector = pkgs.writeShellApplication {
+    name = "jellyfin-metrics-collector";
+    runtimeInputs = with pkgs; [
+      curl
+      jq
+    ];
+    text = ''
+      API_KEY=$(cat "$CREDENTIALS_DIRECTORY/jellyfin-api-key")
+      JELLYFIN="http://127.0.0.1:${toString service_configs.ports.private.jellyfin.port}"
+
+      if response=$(curl -sf --max-time 5 "''${JELLYFIN}/Sessions?api_key=''${API_KEY}"); then
+        active_streams=$(echo "$response" | jq '[.[] | select(.NowPlayingItem != null)] | length')
+      else
+        active_streams=0
+      fi
+
+      {
+        echo '# HELP jellyfin_active_streams Number of currently active Jellyfin streams'
+        echo '# TYPE jellyfin_active_streams gauge'
+        echo "jellyfin_active_streams $active_streams"
+      } > "${textfileDir}/jellyfin.prom.$$.tmp"
+      mv "${textfileDir}/jellyfin.prom.$$.tmp" "${textfileDir}/jellyfin.prom"
+    '';
+  };
+in
+lib.mkIf (config.services.grafana.enable && config.services.jellyfin.enable) {
+  systemd.services.jellyfin-metrics-collector = {
+    description = "Collect Jellyfin metrics for Prometheus";
+    after = [ "network.target" ];
+    serviceConfig = {
+      Type = "oneshot";
+      ExecStart = lib.getExe jellyfinCollector;
+      LoadCredential = "jellyfin-api-key:${config.age.secrets.jellyfin-api-key.path}";
+    };
+  };
+
+  systemd.timers.jellyfin-metrics-collector = {
+    wantedBy = [ "timers.target" ];
+    timerConfig = {
+      OnCalendar = "*:*:0/30";
+      RandomizedDelaySec = "5s";
+    };
+  };
+}