why the fuck was i zeroing the stats?

switched to socketed sccache server
wrote a systemd service to spin that socket up

custom/modules/kernel.nix

@@ -6,6 +6,7 @@
   kernelPatches ? [ ],
   extraConfig ? "",
   sccacheDir ? "/var/cache/sccache",
+  sccacheServerUds ? "/run/sccache/server.sock",
   enforceSccache ? true,
 }:
 
@@ -62,6 +63,7 @@ pkgs.callPackage (
       pkgs.writeShellScriptBin name ''
         set -euo pipefail
         export SCCACHE_DIR=${lib.escapeShellArg sccacheDir}
+        export SCCACHE_SERVER_UDS=${lib.escapeShellArg sccacheServerUds}
         if [ -n "''${SCCACHE_ENFORCE_MARKER-}" ]; then
           : > "''${SCCACHE_ENFORCE_MARKER}"
         fi
@@ -74,6 +76,7 @@ pkgs.callPackage (
     rustcSccache = pkgs.writeShellScriptBin "rustc" ''
       set -euo pipefail
       export SCCACHE_DIR=${lib.escapeShellArg sccacheDir}
+      export SCCACHE_SERVER_UDS=${lib.escapeShellArg sccacheServerUds}
       if [ -n "''${SCCACHE_ENFORCE_MARKER-}" ]; then
         : > "''${SCCACHE_ENFORCE_MARKER}"
       fi
@@ -83,6 +86,7 @@ pkgs.callPackage (
     hostrustcSccache = pkgs.writeShellScriptBin "rustc" ''
       set -euo pipefail
       export SCCACHE_DIR=${lib.escapeShellArg sccacheDir}
+      export SCCACHE_SERVER_UDS=${lib.escapeShellArg sccacheServerUds}
       if [ -n "''${SCCACHE_ENFORCE_MARKER-}" ]; then
         : > "''${SCCACHE_ENFORCE_MARKER}"
       fi
@@ -131,18 +135,19 @@ pkgs.callPackage (
         ]
         ;
 
-      # Start with clean stats so the build-phase check reports only this build.
       preBuild =
         (args.preBuild or "")
         + lib.optionalString enforceSccache ''
-          ${pkgs.sccache}/bin/sccache --start-server || true
-          ${pkgs.sccache}/bin/sccache --zero-stats || true
+          export SCCACHE_DIR=${lib.escapeShellArg sccacheDir}
+          export SCCACHE_SERVER_UDS=${lib.escapeShellArg sccacheServerUds}
         '';
 
       buildPhase =
         if enforceSccache then
           ''
             runHook preBuild
+            export SCCACHE_DIR=${lib.escapeShellArg sccacheDir}
+            export SCCACHE_SERVER_UDS=${lib.escapeShellArg sccacheServerUds}
             export SCCACHE_ENFORCE_MARKER="$NIX_BUILD_TOP/.sccache-used"
             rm -f "$SCCACHE_ENFORCE_MARKER"
             make "''${makeFlags[@]}" "''${buildFlags[@]}"

flake.nix

@@ -113,6 +113,7 @@
                   "thek0tyara"
                 ];
                 extra-sandbox-paths = [
+                  "/run/sccache"
                   "/var/cache/sccache"
                 ];
                 download-buffer-size = 160000000;
@@ -121,6 +122,29 @@
                 # setgid, чтобы файлы/папки сохраняли группу nixbld
                 "d /var/cache/sccache 2770 root nixbld - -"
               ];
+              systemd.services.sccache = {
+                description = "Shared sccache server for Nix builds";
+                after = [ "local-fs.target" ];
+                wantedBy = [ "multi-user.target" ];
+                serviceConfig = {
+                  Type = "simple";
+                  User = "root";
+                  Group = "nixbld";
+                  RuntimeDirectory = "sccache";
+                  RuntimeDirectoryMode = "0770";
+                  UMask = "0007";
+                  ExecStart = "${pkgs.sccache}/bin/sccache";
+                  Restart = "always";
+                  RestartSec = 2;
+                };
+                environment = {
+                  SCCACHE_DIR = "/var/cache/sccache";
+                  SCCACHE_SERVER_UDS = "/run/sccache/server.sock";
+                  SCCACHE_IDLE_TIMEOUT = "0";
+                  SCCACHE_START_SERVER = "1";
+                  SCCACHE_NO_DAEMON = "1";
+                };
+              };
               boot = {
                 loader = {
                   systemd-boot.enable = true;