services/prometheus/exporters: add scaphandre

nixos/doc/manual/release-notes/rl-2311.section.md

@@ -76,6 +76,8 @@
 
 - `services.nginx` gained a `defaultListen` option at server-level with support for PROXY protocol listeners, also `proxyProtocol` is now exposed in `services.nginx.virtualHosts.<name>.listen` option. It is now possible to run PROXY listeners and non-PROXY listeners at a server-level, see [#213510](https://github.com/NixOS/nixpkgs/pull/213510/) for more details.
 
+- `services.prometheus.exporters` has a new exporter to monitor electrical power consumption based on PowercapRAPL sensor called [Scaphandre](https://github.com/hubblo-org/scaphandre), see [#239803](https://github.com/NixOS/nixpkgs/pull/239803) for more details.
+
 ## Nixpkgs internals {#sec-release-23.11-nixpkgs-internals}
 
 - The `qemu-vm.nix` module by default now identifies block devices via

nixos/modules/services/monitoring/prometheus/exporters.nix

@@ -65,6 +65,7 @@ let
     "redis"
     "rspamd"
     "rtl_433"
+    "scaphandre"
     "script"
     "shelly"
     "snmp"
@@ -301,6 +302,21 @@ in
         Please specify either 'services.prometheus.exporters.sql.configuration' or
           'services.prometheus.exporters.sql.configFile'
       '';
+    } {
+      assertion = cfg.scaphandre.enable -> (pkgs.stdenv.hostPlatform.isx86_64 == true);
+      message = ''
+        Only x86_64 host platform architecture is not supported.
+      '';
+    } {
+      assertion = cfg.scaphandre.enable -> ((lib.kernel.whenHelpers pkgs.linux.version).whenOlder "5.11" true).condition == false;
+      message = ''
+        A kernel version older than '5.11' is required. ${pkgs.linux.version}
+      '';
+    } {
+      assertion = cfg.scaphandre.enable -> (builtins.elem "intel_rapl_common" config.boot.kernelModules);
+      message = ''
+        Please enable 'intel_rapl_common' in 'boot.kernelModules'.
+      '';
     } ] ++ (flip map (attrNames exporterOpts) (exporter: {
       assertion = cfg.${exporter}.firewallFilter != null -> cfg.${exporter}.openFirewall;
       message = ''

nixos/modules/services/monitoring/prometheus/exporters/scaphandre.nix

@@ -0,0 +1,31 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  logPrefix = "services.prometheus.exporter.scaphandre";
+  cfg = config.services.prometheus.exporters.scaphandre;
+in {
+  port = 8080;
+  extraOpts = {
+    telemetryPath = mkOption {
+      type = types.str;
+      default = "/metrics";
+      description = lib.mdDoc ''
+        Path under which to expose metrics.
+      '';
+    };
+  };
+
+  serviceOpts = {
+    serviceConfig = {
+      ExecStart = ''
+        ${pkgs.scaphandre}/bin/scaphandre prometheus \
+          --address ${cfg.listenAddress} \
+          --port ${toString cfg.port} \
+          --suffix ${cfg.telemetryPath} \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+    };
+  };
+}

nixos/tests/prometheus-exporters.nix

@@ -1085,6 +1085,22 @@ let
       '';
     };
 
+    scaphandre = {
+      exporterConfig = {
+        enable = true;
+      };
+      metricProvider = {
+        boot.kernelModules = [ "intel_rapl_common" ];
+      };
+      exporterTest = ''
+        wait_for_unit("prometheus-scaphandre-exporter.service")
+        wait_for_open_port(8080)
+        wait_until_succeeds(
+            "curl -sSf 'localhost:8080/metrics'"
+        )
+      '';
+    };
+
     shelly = {
       exporterConfig = {
         enable = true;

pkgs/servers/scaphandre/default.nix

@@ -55,7 +55,7 @@ rustPlatform.buildRustPackage rec {
     description = "Electrical power consumption metrology agent";
     homepage = "https://github.com/hubblo-org/scaphandre";
     license = licenses.asl20;
-    platforms = platforms.linux;
+    platforms = with platforms; [ "x86_64-linux"];
     maintainers = with maintainers; [ gaelreyrol ];
   };
 }