feat(monitoring): collect homelab UPS metrics

hosts/idols-aquamarine/monitoring/victoriametrics.nix

@@ -71,6 +71,22 @@
             }
           ];
         }
+        {
+          job_name = "nut-exporter-homelab-ups";
+          scrape_interval = "30s";
+          metrics_path = "/ups_metrics";
+          params.ups = [ "homelab" ];
+          static_configs = [
+            {
+              targets = [ "${myvars.networking.hostsAddr.kubevirt-shushou.ipv4}:9199" ];
+              labels.type = "app";
+              labels.app = "nut";
+              labels.host = "kubevirt-shushou";
+              labels.env = "homelab";
+              labels.cluster = "homelab";
+            }
+          ];
+        }
         {
           job_name = "postgres-exporter";
           scrape_interval = "30s";

hosts/k8s/kubevirt-shushou/ups.nix

@@ -0,0 +1,51 @@
+{ myvars, ... }:
+let
+  hostAddress = myvars.networking.hostsAddr.kubevirt-shushou.ipv4;
+in
+{
+  power.ups = {
+    enable = true;
+    mode = "standalone";
+
+    # Metrics only. Coordinated shutdown of all homelab hosts is a separate feature.
+    upsmon = {
+      enable = false;
+      settings.POWERDOWNFLAG = null;
+    };
+
+    upsd.listen = [
+      {
+        address = "127.0.0.1";
+        port = 3493;
+      }
+    ];
+
+    ups.homelab = {
+      driver = "nutdrv_qx";
+      port = "auto";
+      description = "Homelab UPS";
+      directives = [
+        "vendorid = 0665"
+        "productid = 5161"
+      ];
+    };
+  };
+
+  services.prometheus.exporters.nut = {
+    enable = true;
+    listenAddress = hostAddress;
+    port = 9199;
+    nutServer = "127.0.0.1";
+
+    # The NixOS module omits --nut.vars_enable when nutVariables is empty, but the exporter needs
+    # an explicitly empty value to export every numeric NUT variable.
+    extraFlags = [ "--nut.vars_enable=" ];
+  };
+
+  systemd.services.prometheus-nut-exporter = {
+    after = [
+      "upsd.service"
+      "upsdrv.service"
+    ];
+  };
+}

outputs/x86_64-linux/tests/ups-metrics/expected.nix

@@ -0,0 +1,44 @@
+{
+  nut = {
+    enable = true;
+    mode = "standalone";
+    upsmonEnable = false;
+    killPowerEnable = false;
+    upsdListen = [
+      {
+        address = "127.0.0.1";
+        port = 3493;
+      }
+    ];
+    driver = "nutdrv_qx";
+    port = "auto";
+    vendorId = true;
+    productId = true;
+  };
+
+  exporter = {
+    enable = true;
+    listenAddress = "192.168.5.182";
+    port = 9199;
+    nutServer = "127.0.0.1";
+    exportsAllNumericVariables = true;
+    startsAfterNut = true;
+    requiresNut = false;
+  };
+
+  victoriametricsJobCount = 1;
+  victoriametrics = {
+    job_name = "nut-exporter-homelab-ups";
+    scrape_interval = "30s";
+    metrics_path = "/ups_metrics";
+    params.ups = [ "homelab" ];
+    target = "192.168.5.182:9199";
+    labels = {
+      type = "app";
+      app = "nut";
+      host = "kubevirt-shushou";
+      env = "homelab";
+      cluster = "homelab";
+    };
+  };
+}

outputs/x86_64-linux/tests/ups-metrics/expr.nix

@@ -0,0 +1,63 @@
+{
+  lib,
+  outputs,
+  ...
+}:
+let
+  shushou = outputs.nixosConfigurations.kubevirt-shushou.config;
+  aquamarine = outputs.nixosConfigurations.aquamarine.config;
+  ups = shushou.power.ups.ups.homelab or { };
+  exporter = shushou.services.prometheus.exporters.nut;
+  exporterService =
+    shushou.systemd.services.prometheus-nut-exporter or {
+      after = [ ];
+      requires = [ ];
+    };
+  scrapeJobs = builtins.filter (
+    job: (job.job_name or "") == "nut-exporter-homelab-ups"
+  ) aquamarine.services.victoriametrics.prometheusConfig.scrape_configs;
+  scrapeJob = if builtins.length scrapeJobs == 1 then builtins.head scrapeJobs else null;
+in
+{
+  nut = {
+    enable = shushou.power.ups.enable;
+    mode = shushou.power.ups.mode;
+    upsmonEnable = shushou.power.ups.upsmon.enable;
+    killPowerEnable = shushou.systemd.services.ups-killpower.enable or false;
+    upsdListen = shushou.power.ups.upsd.listen;
+    driver = ups.driver or null;
+    port = ups.port or null;
+    vendorId = builtins.elem "vendorid = 0665" (ups.directives or [ ]);
+    productId = builtins.elem "productid = 5161" (ups.directives or [ ]);
+  };
+
+  exporter = {
+    enable = exporter.enable;
+    listenAddress = exporter.listenAddress;
+    port = exporter.port;
+    nutServer = exporter.nutServer;
+    exportsAllNumericVariables = builtins.elem "--nut.vars_enable=" exporter.extraFlags;
+    startsAfterNut =
+      builtins.elem "upsd.service" exporterService.after
+      && builtins.elem "upsdrv.service" exporterService.after;
+    requiresNut =
+      builtins.elem "upsd.service" exporterService.requires
+      && builtins.elem "upsdrv.service" exporterService.requires;
+  };
+
+  victoriametricsJobCount = builtins.length scrapeJobs;
+  victoriametrics =
+    if scrapeJob == null then
+      null
+    else
+      {
+        inherit (scrapeJob)
+          job_name
+          scrape_interval
+          metrics_path
+          params
+          ;
+        target = builtins.head (builtins.head scrapeJob.static_configs).targets;
+        labels = (builtins.head scrapeJob.static_configs).labels;
+      };
+}