org: monitor kfet

machines/hackens-org/_configuration.nix

@@ -22,6 +22,7 @@
       ./webpass.nix
       ./prometheus.nix
       ./grafana.nix
+      ./kfet-monitor
     ];
 
   time.timeZone = "Europe/Paris";

machines/hackens-org/kfet-monitor/default.nix

@@ -0,0 +1,25 @@
+{ lib, pkgs, ...}:
+let
+  wsScraper = pkgs.callPackage ./websocket-exporter.nix {};
+in
+{
+  systemd.services.kfet-open-recorder = {
+    environment = {
+      WEBSOCKET_EXPORTER_URI = "wss://cof.ens.fr/ws/k-fet/open";
+      WEBSOCKET_EXPORTER_MATCH_TYPE = "contains";
+      WEBSOCKET_EXPORTER_EXPECTED_MESSAGE = "open";
+      WEBSOCKET_EXPORTER_LISTEN_ADDR = "127.0.0.1";
+    };
+    wantedBy = [ "multi-user.target" ];
+    after = [ "network.target" ];
+    wants = [ "network.target" ];
+
+    serviceConfig = {
+      ExecStart = "${lib.getExe wsScraper}";
+      Restart = "always";
+      RestartSec = 5;
+      DynamicUser = true;
+      StateDirectory = "kfet-open-recorder";
+    };
+  };
+}

machines/hackens-org/kfet-monitor/websocket-exporter.nix

@@ -0,0 +1,35 @@
+{ lib
+, python3
+, fetchFromGitHub
+}:
+
+python3.pkgs.buildPythonApplication rec {
+  pname = "blackbox-websocket-exporter";
+  version = "unstable-2021-12-15";
+  pyproject = true;
+
+  src = fetchFromGitHub {
+    owner = "smohsensh";
+    repo = "blackbox-websocket-exporter";
+    rev = "6f9f32396f740fe606bf1b0118a27ad5caa3d9a6";
+    hash = "sha256-+G7xw5631TllDGNzVK9swbSNfVu4r4glbYIblEa0WqA=";
+  };
+
+  nativeBuildInputs = [
+    python3.pkgs.setuptools
+    python3.pkgs.wheel
+  ];
+
+  propagatedBuildInputs = with python3.pkgs; [
+    prometheus-client
+    websockets
+  ];
+
+  meta = with lib; {
+    description = "A Blackbox Websocket Uptime Exporter for Prometheus";
+    homepage = "https://github.com/smohsensh/blackbox-websocket-exporter";
+    license = licenses.mit;
+    maintainers = with maintainers; [ ];
+    mainProgram = "websocket_exporter";
+  };
+}

machines/hackens-org/prometheus.nix

@@ -20,6 +20,10 @@ in
 
     webExternalUrl = "https://${host}";
 
+    retentionTime = "5y";
+
+    extraFlags = "--storage.tsdb.retention.size=2GB";
+
     rules = [ ''
       groups:
         - name: Chrony
@@ -42,6 +46,10 @@ in
         job_name = "chrony";
         static_configs = [ { targets = [ "10.10.10.3:9123" ]; } ];
       }
+      {
+        job_name = "kfet";
+        static_configs = [ { targets = [ "127.0.0.1:9802" ]; } ];
+      }
     ];
   };