extend nixpkgs's lib instead

flake.nix

@@ -135,37 +135,8 @@
         };
       };
 
-      serviceMountDeps = serviceName: dirs: pkgs: {
+      pkgs = nixpkgs.legacyPackages.x86_64-linux;
-        systemd.services."${serviceName}_mounts" =
+      lib = import ./lib.nix { inherit inputs pkgs; };
-          let
-            lib = nixpkgs.lib;
-            zfslistmounted = pkgs.writeShellApplication {
-              name = "zfslistmounted";
-              runtimeInputs = with pkgs; [
-                zfs
-                gnugrep
-                gawk
-                coreutils
-              ];
-              text = ''
-                #!/bin/sh
-                zfs list -o mountpoint,mounted -H | awk '$2 == "yes" {print $1}' | grep -c '${lib.strings.concatStringsSep "\|" dirs}' | grep -Fq ${toString (lib.length dirs)}
-              '';
-            };
-          in
-          {
-            unitConfig.Wants = "zfs.target";
-            serviceConfig = {
-              Type = "oneshot";
-              RemainAfterExit = true;
-              ExecStart = nixpkgs.lib.getExe zfslistmounted;
-            };
-          };
-
-        systemd.services.${serviceName} = {
-          wants = [ "${serviceName}_mounts.service" ];
-        };
-      };
     in
     {
       formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt-rfc-style;
@@ -177,32 +148,8 @@
             eth_interface
             service_configs
             inputs
-            serviceMountDeps
+            lib
             ;
-
-          # stolen from: https://stackoverflow.com/a/42398526
-          optimizeWithFlags =
-            pkg: flags:
-            nixpkgs.lib.overrideDerivation pkg (
-              old:
-              let
-                newflags = nixpkgs.lib.foldl' (acc: x: "${acc} ${x}") "" flags;
-                oldflags =
-                  if (nixpkgs.lib.hasAttr "NIX_CFLAGS_COMPILE" old) then "${old.NIX_CFLAGS_COMPILE}" else "";
-              in
-              {
-                NIX_CFLAGS_COMPILE = "${oldflags} ${newflags}";
-                # stdenv = pkgs.clang19Stdenv;
-              }
-            );
-
-          optimizePackage =
-            pkg:
-            optimizeWithFlags pkg [
-              "-O3"
-              "-march=znver3"
-              "-mtune=znver3"
-            ];
         };
         modules =
           [

lib.nix

@@ -0,0 +1,66 @@
+{
+  inputs,
+  pkgs,
+  ...
+}:
+inputs.nixpkgs.lib.extend (
+  final: prev:
+  let
+    lib = prev;
+  in
+  {
+    ensureZfsMounts =
+      dirs:
+      pkgs.writeShellApplication {
+        name = "zfslistmounted";
+        runtimeInputs = with pkgs; [
+          zfs
+          gnugrep
+          gawk
+          coreutils
+        ];
+        text = ''
+          #!/bin/sh
+          zfs list -o mountpoint,mounted -H | awk '$2 == "yes" {print $1}' | grep -c '${lib.strings.concatStringsSep "\|" dirs}' | grep -Fq ${toString (lib.length dirs)}
+        '';
+      };
+
+    serviceMountDeps = serviceName: dirs: {
+      systemd.services."${serviceName}_mounts" = {
+        unitConfig.Wants = "zfs.target";
+        serviceConfig = {
+          Type = "oneshot";
+          RemainAfterExit = true;
+          ExecStart = lib.getExe (final.ensureZfsMounts dirs);
+        };
+      };
+
+      systemd.services.${serviceName} = {
+        wants = [ "${serviceName}_mounts.service" ];
+      };
+    };
+
+    # stolen from: https://stackoverflow.com/a/42398526
+    optimizeWithFlags =
+      pkg: flags:
+      lib.overrideDerivation pkg (
+        old:
+        let
+          newflags = lib.foldl' (acc: x: "${acc} ${x}") "" flags;
+          oldflags = if (lib.hasAttr "NIX_CFLAGS_COMPILE" old) then "${old.NIX_CFLAGS_COMPILE}" else "";
+        in
+        {
+          NIX_CFLAGS_COMPILE = "${oldflags} ${newflags}";
+          # stdenv = pkgs.clang19Stdenv;
+        }
+      );
+
+    optimizePackage =
+      pkg:
+      final.optimizeWithFlags pkg [
+        "-O3"
+        "-march=znver3"
+        "-mtune=znver3"
+      ];
+  }
+)

services/caddy.nix

@@ -3,15 +3,15 @@
   service_configs,
   username,
   pkgs,
-  serviceMountDeps,
+  lib,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "caddy" [
+    (lib.serviceMountDeps "caddy" [
       "/var/lib/caddy"
       service_configs.https.data_dir
-    ] pkgs)
+    ])
   ];
 
   services.caddy = {

services/gitea.nix

@@ -1,14 +1,14 @@
 {
   pkgs,
+  lib,
   config,
   service_configs,
   username,
-  serviceMountDeps,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "gitea" [ config.services.gitea.stateDir ] pkgs)
+    (lib.serviceMountDeps "gitea" [ config.services.gitea.stateDir ])
   ];
 
   services.gitea = {

services/immich.nix

@@ -3,13 +3,13 @@
   pkgs,
   config,
   username,
-  serviceMountDeps,
+  lib,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "immich-server" [ config.services.immich.mediaLocation ] pkgs)
+    (lib.serviceMountDeps "immich-server" [ config.services.immich.mediaLocation ])
-    (serviceMountDeps "immich-machine-learning" [ config.services.immich.mediaLocation ] pkgs)
+    (lib.serviceMountDeps "immich-machine-learning" [ config.services.immich.mediaLocation ])
   ];
 
   services.immich = {

services/jellyfin.nix

@@ -3,23 +3,22 @@
   config,
   service_configs,
   username,
-  serviceMountDeps,
+  lib,
-  optimizePackage,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "jellyfin" [
+    (lib.serviceMountDeps "jellyfin" [
       config.services.jellyfin.dataDir
       config.services.jellyfin.cacheDir
-    ] pkgs)
+    ])
   ];
 
   services.jellyfin = {
     enable = true;
     # used for local streaming
     openFirewall = true;
-    package = pkgs.jellyfin.override { jellyfin-ffmpeg = (optimizePackage pkgs.jellyfin-ffmpeg); };
+    package = pkgs.jellyfin.override { jellyfin-ffmpeg = (lib.optimizePackage pkgs.jellyfin-ffmpeg); };
 
     dataDir = service_configs.jellyfin.dataDir;
     cacheDir = service_configs.jellyfin.cacheDir;

services/llama-cpp.nix

@@ -3,7 +3,6 @@
   service_configs,
   config,
   inputs,
-  optimizePackage,
   lib,
   ...
 }:
@@ -19,7 +18,7 @@
     port = service_configs.ports.llama_cpp;
     host = "0.0.0.0";
     # vulkan broken: https://github.com/ggml-org/llama.cpp/issues/13801
-    package = (optimizePackage inputs.llamacpp.packages.${pkgs.system}.default);
+    package = (lib.optimizePackage inputs.llamacpp.packages.${pkgs.system}.default);
     extraFlags = [
       # "-ngl"
       # "9999"

services/minecraft.nix

@@ -4,14 +4,13 @@
   lib,
   username,
   config,
-  serviceMountDeps,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "minecraft-server-${service_configs.minecraft.server_name}" [
+    (lib.serviceMountDeps "minecraft-server-${service_configs.minecraft.server_name}" [
       "${service_configs.minecraft.parent_dir}/${service_configs.minecraft.server_name}"
-    ] pkgs)
+    ])
   ];
 
   environment.systemPackages = [

services/postgresql.nix

@@ -3,12 +3,12 @@
   config,
   username,
   service_configs,
-  serviceMountDeps,
+  lib,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "postgresql" [ config.services.postgresql.dataDir ] pkgs)
+    (lib.serviceMountDeps "postgresql" [ config.services.postgresql.dataDir ])
   ];
 
   services.postgresql = {

services/qbittorrent.nix

@@ -4,16 +4,15 @@
   service_configs,
   username,
   lib,
-  serviceMountDeps,
   ...
 }:
 {
   imports = [
-    (serviceMountDeps "qbittorrent" [
+    (lib.serviceMountDeps "qbittorrent" [
       service_configs.torrents_path
       config.services.qbittorrent.serverConfig.Preferences.Downloads.TempPath
       "/var/lib/qBittorrent/qBittorrent"
-    ] pkgs)
+    ])
   ];
 
   # network namespace that is proxied through mullvad

services/soulseek.nix

@@ -4,7 +4,6 @@
   lib,
   service_configs,
   username,
-  serviceMountDeps,
   ...
 }:
 let
@@ -12,11 +11,11 @@ let
 in
 {
   imports = [
-    (serviceMountDeps "slskd" [
+    (lib.serviceMountDeps "slskd" [
       service_configs.slskd.base
       # service_configs.slskd.downloads
       # service_configs.slskd.incomplete
-    ] pkgs)
+    ])
   ];
 
   users.groups."music" = { };