Implement exporter using nocap from nostr-watch along with tests

2026-03-22 14:55:22 -07:00
parent 9c6aef1d92
commit 0531a23680
17 changed files with 1576 additions and 7 deletions
@@ -0,0 +1,174 @@
+{
+  description = "Nostr relay Prometheus exporter";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      inherit (nixpkgs.lib) genAttrs;
+      systems = [ "x86_64-linux" "aarch64-linux" ];
+      forAllSystems = genAttrs systems;
+
+      mkPackage = pkgs:
+        let
+          pname = "relay-exporter";
+          version = "0.1.0";
+          src = pkgs.lib.cleanSourceWith {
+            src = ./.;
+            filter = path: type:
+              !(pkgs.lib.hasInfix "/.git/" path)
+              && !(pkgs.lib.hasInfix "/node_modules/" path)
+              && !(pkgs.lib.hasInfix "/dist/" path);
+          };
+        in
+        pkgs.stdenv.mkDerivation {
+          inherit pname version;
+          inherit src;
+
+          nativeBuildInputs = [
+            pkgs.nodejs_22
+            pkgs.pnpm.configHook
+            pkgs.makeWrapper
+          ];
+
+          pnpmDeps = pkgs.pnpm.fetchDeps {
+            inherit pname version src;
+            fetcherVersion = 1;
+            hash = "sha256-n3pn4NVBVauwE2FWfMsulmn+KgCkcV32XJD6vX1NIB0=";
+          };
+
+          buildPhase = ''
+            runHook preBuild
+            pnpm run build
+            runHook postBuild
+          '';
+
+          installPhase = ''
+            runHook preInstall
+            mkdir -p $out/app $out/bin
+            cp -r dist package.json node_modules $out/app/
+            makeWrapper ${pkgs.nodejs_22}/bin/node $out/bin/relay-exporter \
+              --set NODE_ENV production \
+              --add-flags "$out/app/dist/index.js"
+            runHook postInstall
+          '';
+
+          meta = {
+            description = "Prometheus exporter for Nostr relay health checks";
+            mainProgram = "relay-exporter";
+            license = pkgs.lib.licenses.mit;
+            platforms = pkgs.lib.platforms.linux;
+          };
+        };
+    in
+    rec {
+      packages = forAllSystems (system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+          pkg = mkPackage pkgs;
+        in
+        {
+          relay-exporter = pkg;
+          default = pkg;
+        });
+
+      devShells = forAllSystems (system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+        in
+        {
+          default = pkgs.mkShell {
+            packages = [
+              pkgs.nodejs_22
+              pkgs.pnpm_10
+            ];
+          };
+        });
+
+      overlays.default = final: prev: {
+        relay-exporter = self.packages.${prev.stdenv.hostPlatform.system}.relay-exporter;
+      };
+
+      nixosModules.default =
+        { config, lib, pkgs, ... }:
+        let
+          inherit (lib) mkEnableOption mkIf mkOption types;
+          cfg = config.services.relay-exporter;
+          system = pkgs.stdenv.hostPlatform.system;
+          defaultPackage = self.packages.${system}.relay-exporter;
+        in
+        {
+          options.services.relay-exporter = {
+            enable = mkEnableOption "relay-exporter service";
+
+            package = mkOption {
+              type = types.package;
+              default = defaultPackage;
+              defaultText = "self.packages.${system}.relay-exporter";
+              description = "Derivation that provides relay-exporter.";
+            };
+
+            port = mkOption {
+              type = types.port;
+              default = 9464;
+              description = "HTTP listen port for relay-exporter.";
+            };
+
+            listenAddr = mkOption {
+              type = types.str;
+              default = "0.0.0.0";
+              description = "Listen address for relay-exporter.";
+            };
+
+            stateDirectory = mkOption {
+              type = types.str;
+              default = "relay-exporter";
+              description = "Name of the state directory managed by systemd.";
+            };
+
+            environment = mkOption {
+              type = types.attrsOf types.str;
+              default = { };
+              description = "Additional environment variables for relay-exporter.";
+            };
+
+            environmentFile = mkOption {
+              type = types.nullOr types.path;
+              default = null;
+              description = "Optional environment file consumed by systemd.";
+            };
+          };
+
+          config = mkIf cfg.enable {
+            systemd.services.relay-exporter = {
+              description = "Nostr relay Prometheus exporter";
+              wantedBy = [ "multi-user.target" ];
+              after = [ "network-online.target" ];
+              wants = [ "network-online.target" ];
+
+              environment = {
+                NODE_ENV = "production";
+                PORT = builtins.toString cfg.port;
+                LISTEN_ADDR = cfg.listenAddr;
+              } // cfg.environment;
+
+              serviceConfig =
+                {
+                  Type = "simple";
+                  ExecStart = "${cfg.package}/bin/relay-exporter";
+                  DynamicUser = true;
+                  StateDirectory = cfg.stateDirectory;
+                  WorkingDirectory = "/var/lib/${cfg.stateDirectory}";
+                  Restart = "on-failure";
+                  RestartSec = 3;
+                }
+                // lib.optionalAttrs (cfg.environmentFile != null) {
+                  EnvironmentFile = cfg.environmentFile;
+                };
+            };
+          };
+        };
+    };
+}