add synapse metrics

nixos/pkgs/default.nix

@@ -6,6 +6,8 @@ final: prev: {
     '';
   });
 
+  vmagent = prev.callPackage ./vmagent { };
+
   v = {
     unbound = prev.unbound.override {
       withSystemd = true;

nixos/pkgs/vmagent/default.nix

@@ -0,0 +1,23 @@
+{ lib, fetchFromGitHub, buildGoModule }:
+buildGoModule rec {
+  pname = "vmagent";
+  version = "1.79.0";
+
+  src = fetchFromGitHub {
+    owner = "VictoriaMetrics";
+    repo = "VictoriaMetrics";
+    rev = "v${version}";
+    sha256 = "sha256-+LirbGbKeazXMtgVh5kZP+KEk/fDbSxceZ26OlE0hbY=";
+  };
+
+  vendorSha256 = null;
+
+  subPackages = [ "app/vmagent" ];
+
+  meta = with lib; {
+    description = "VictoriaMetrics metrics scraper";
+    homepage = "https://github.com/VictoriaMetrics/VictoriaMetrics/tree/master/app/vmagent";
+    license = licenses.asl20;
+    platforms = platforms.linux;
+  };
+}