From f463644f1b3d2488a6ddecb0b5cb2936777f7ef8 Mon Sep 17 00:00:00 2001
From: Romain Paquet <rpqt@rpqt.fr>
Date: Mon, 25 Aug 2025 07:21:21 +0200
Subject: [PATCH] create prometheus clan service

---
 clanServices/flake-module.nix            |   5 ++
 clanServices/prometheus/default.nix      | 110 +++++++++++++++++++++++
 clanServices/prometheus/flake-module.nix |   4 +
 flake.nix                                |   1 +
 4 files changed, 120 insertions(+)
 create mode 100644 clanServices/flake-module.nix
 create mode 100644 clanServices/prometheus/default.nix
 create mode 100644 clanServices/prometheus/flake-module.nix

diff --git a/clanServices/flake-module.nix b/clanServices/flake-module.nix
new file mode 100644
index 0000000..64844d9
--- /dev/null
+++ b/clanServices/flake-module.nix
@@ -0,0 +1,5 @@
+{
+  imports = [
+    ./prometheus/flake-module.nix
+  ];
+}
diff --git a/clanServices/prometheus/default.nix b/clanServices/prometheus/default.nix
new file mode 100644
index 0000000..cdb929e
--- /dev/null
+++ b/clanServices/prometheus/default.nix
@@ -0,0 +1,110 @@
+{ self, ... }:
+{ lib, ... }:
+{
+  _class = "clan.service";
+  manifest.name = "prometheus";
+
+  # Only works with zerotier (until a unified network module is ready)
+
+  roles.scraper = {
+    interface = {
+      options.extraScrapeConfigs = lib.mkOption {
+        type = lib.types.listOf lib.types.attrs;
+        description = "A list of additional scrape configurations.";
+      };
+    };
+
+    perInstance =
+      {
+        settings,
+        roles,
+        ...
+      }:
+      {
+        nixosModule =
+          { config, lib, ... }:
+          {
+            services.prometheus.enable = true;
+            services.prometheus.scrapeConfigs =
+              let
+                allExporters = lib.unique (
+                  lib.concatLists (
+                    lib.map (machine: lib.attrNames machine.settings.exporters) (lib.attrValues roles.target.machines)
+                  )
+                );
+                hasExporter =
+                  exporter: machine: lib.hasAttr exporter roles.target.machines.${machine}.settings.exporters;
+                mkScrapeConfig = (
+                  exporter:
+                  let
+                    machinesWithExporter = lib.filter (hasExporter exporter) (lib.attrNames roles.target.machines);
+                  in
+                  {
+                    job_name = exporter;
+                    static_configs = lib.map (machineName: {
+                      targets =
+                        let
+                          targetConfig = self.nixosConfigurations.${machineName}.config;
+                          targetHost = targetConfig.clan.core.vars.generators.zerotier.files.zerotier-ip.value;
+                        in
+                        [
+                          "${targetHost}:${toString targetConfig.services.prometheus.exporters.${exporter}.port}"
+                        ];
+                      labels.instance = machineName;
+                    }) machinesWithExporter;
+                  }
+                );
+              in
+              (lib.map mkScrapeConfig allExporters) ++ settings.extraScrapeConfigs;
+
+            clan.core.state.prometheus.folders = [ config.services.prometheus.stateDir ];
+          };
+      };
+  };
+
+  roles.target = {
+    interface =
+      { lib, ... }:
+      {
+        options = {
+          exporters = lib.mkOption {
+            type = lib.types.attrs;
+            default = { };
+            example = {
+              node = {
+                enabledCollectors = [ "systemd" ];
+                port = 9002;
+              };
+            };
+            description = "Attribute set of exporters to enable";
+          };
+        };
+      };
+
+    perInstance =
+      {
+        instanceName,
+        settings,
+        machine,
+        roles,
+        ...
+      }:
+      {
+        nixosModule =
+          { config, lib, ... }:
+          {
+            services.prometheus.exporters = builtins.mapAttrs (
+              name: exporterSettings:
+              exporterSettings
+              // {
+                enable = true;
+              }
+            ) settings.exporters;
+
+            networking.firewall.interfaces."zts7mq7onf".allowedTCPPorts = lib.map (
+              exporterName: config.services.prometheus.exporters.${exporterName}.port
+            ) (lib.attrNames settings.exporters);
+          };
+      };
+  };
+}
diff --git a/clanServices/prometheus/flake-module.nix b/clanServices/prometheus/flake-module.nix
new file mode 100644
index 0000000..0c56386
--- /dev/null
+++ b/clanServices/prometheus/flake-module.nix
@@ -0,0 +1,4 @@
+{ self, lib, ... }:
+{
+  clan.modules."@rpqt/prometheus" = lib.modules.importApply ./default.nix { inherit self; };
+}
diff --git a/flake.nix b/flake.nix
index 742d435..40a62d2 100644
--- a/flake.nix
+++ b/flake.nix
@@ -18,6 +18,7 @@
         inputs.clan-core.flakeModules.default
         inputs.nix-topology.flakeModule
 
+        ./clanServices/flake-module.nix
         ./devShells/flake-module.nix
         ./machines/flake-module.nix
         ./modules/flake-module.nix