add: current version and BuildTime for nix build

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1664638641,
-        "narHash": "sha256-r2gVLq9DD1A0Igv4AdkmpuuVykXmKVsJTAJinS/ZFrM=",
+        "lastModified": 1664705630,
+        "narHash": "sha256-MLi1J9tIZQFj8v9RKmG89HJAE5ja3z4ui4Tf9+wG/bM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "cb81a9ca94e7631bc67788d858e214d56571983a",
+        "rev": "f71b215225dec75df6266ff7764d54c2e44ef226",
         "type": "github"
       },
       "original": {

flake.nix

@@ -9,19 +9,49 @@
     utils.lib.eachDefaultSystem
       (system:
         let
-          pkgs = nixpkgs.legacyPackages.${system};
+          pkgs = import nixpkgs {
+            inherit system;
+            overlays = [ self.overlay ];
+          };
         in
-        {
-          packages = rec{
-            clash-meta = pkgs.callPackage ./. { };
-            default = clash-meta;
-          };
-
-          apps = rec {
-            clash-meta = utils.lib.mkApp { drv = self.packages.${system}.clash-meta; };
-            default = clash-meta;
-          };
+        rec {
+          packages.default = pkgs.clash-meta;
         }
-      );
+      ) //
+    (
+      let version = nixpkgs.lib.substring 0 8 self.lastModifiedDate or self.lastModified or "19700101"; in
+      {
+        overlay = final: prev: {
+
+          clash-meta = final.buildGoModule {
+            pname = "clash-meta";
+            inherit version;
+            src = ./.;
+
+            vendorSha256 = "sha256-Af1RgeB6APxKW9m+rm2mkpYSXwAgFTzRyW0GJe9ML+A=";
+
+            # Do not build testing suit
+            excludedPackages = [ "./test" ];
+
+            CGO_ENABLED = 0;
+
+            ldflags = [
+              "-s"
+              "-w"
+              "-X github.com/Dreamacro/clash/constant.Version=dev-${version}"
+              "-X github.com/Dreamacro/clash/constant.BuildTime=${version}"
+            ];
+
+            # Network required 
+            doCheck = false;
+
+            postInstall = ''
+              mv $out/bin/clash $out/bin/clash-meta
+            '';
+
+          };
+        };
+      }
+    );
 }