From 5d85f0eee8417f340424e20345e8ccb86929a73f Mon Sep 17 00:00:00 2001
From: Nudelsalat <nudelsalat@clouz.de>
Date: Wed, 1 Nov 2023 14:04:05 +0100
Subject: [PATCH] nixos/prometheus-ping-exporter: init

---
 .../manual/release-notes/rl-2405.section.md   |  2 +
 .../monitoring/prometheus/exporters.nix       |  1 +
 .../monitoring/prometheus/exporters/ping.nix  | 48 +++++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 100644 nixos/modules/services/monitoring/prometheus/exporters/ping.nix

diff --git a/nixos/doc/manual/release-notes/rl-2405.section.md b/nixos/doc/manual/release-notes/rl-2405.section.md
index c2c8f8acab65..465ea4527e64 100644
--- a/nixos/doc/manual/release-notes/rl-2405.section.md
+++ b/nixos/doc/manual/release-notes/rl-2405.section.md
@@ -29,6 +29,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 - [Anki Sync Server](https://docs.ankiweb.net/sync-server.html), the official sync server built into recent versions of Anki. Available as [services.anki-sync-server](#opt-services.anki-sync-server.enable).
 The pre-existing [services.ankisyncd](#opt-services.ankisyncd.enable) has been marked deprecated and will be dropped after 24.05 due to lack of maintenance of the anki-sync-server softwares.
 
+- [ping_exporter](https://github.com/czerwonk/ping_exporter), a Prometheus exporter for ICMP echo requests. Available as [services.prometheus.exporters.ping](#opt-services.prometheus.exporters.ping.enable).
+
 - [Clevis](https://github.com/latchset/clevis), a pluggable framework for automated decryption, used to unlock encrypted devices in initrd. Available as [boot.initrd.clevis.enable](#opt-boot.initrd.clevis.enable).
 
 - [TuxClocker](https://github.com/Lurkki14/tuxclocker), a hardware control and monitoring program. Available as [programs.tuxclocker](#opt-programs.tuxclocker.enable).
diff --git a/nixos/modules/services/monitoring/prometheus/exporters.nix b/nixos/modules/services/monitoring/prometheus/exporters.nix
index 39abd293b2d1..35db8a7376b1 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters.nix
@@ -64,6 +64,7 @@ let
     "pgbouncer"
     "php-fpm"
     "pihole"
+    "ping"
     "postfix"
     "postgres"
     "process"
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/ping.nix b/nixos/modules/services/monitoring/prometheus/exporters/ping.nix
new file mode 100644
index 000000000000..af78b6bef625
--- /dev/null
+++ b/nixos/modules/services/monitoring/prometheus/exporters/ping.nix
@@ -0,0 +1,48 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.ping;
+
+  settingsFormat = pkgs.formats.yaml {};
+  configFile = settingsFormat.generate "config.yml" cfg.settings;
+in
+{
+  port = 9427;
+  extraOpts = {
+    telemetryPath = mkOption {
+      type = types.str;
+      default = "/metrics";
+      description = ''
+        Path under which to expose metrics.
+      '';
+    };
+
+    settings = mkOption {
+      type = settingsFormat.type;
+      default = {};
+
+      description = lib.mdDoc ''
+        Configuration for ping_exporter, see
+        <https://github.com/czerwonk/ping_exporter>
+        for supported values.
+      '';
+    };
+  };
+
+  serviceOpts = {
+    serviceConfig = {
+      # ping-exporter needs `CAP_NET_RAW` to run as non root https://github.com/czerwonk/ping_exporter#running-as-non-root-user
+      CapabilityBoundingSet = [ "CAP_NET_RAW" ];
+      AmbientCapabilities = [ "CAP_NET_RAW" ];
+      ExecStart = ''
+        ${pkgs.prometheus-ping-exporter}/bin/ping_exporter \
+          --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
+          --web.telemetry-path ${cfg.telemetryPath} \
+          --config.path="${configFile}" \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+    };
+  };
+}