Move convertServiceToNixOS to common lib module (#74)

- Simplifies NixOS installation process to not require also extending lib with nix-snapshotter's lib output.
pdtpartners · Sep 6, 2023 · 4564b74 · 4564b74
1 parent 93cd08f
commit 4564b74
Show file tree

Hide file tree

Showing 6 changed files with 22 additions and 44 deletions.
diff --git a/flake.nix b/flake.nix
@@ -14,17 +14,8 @@
   };
 
   outputs = inputs@{ nixpkgs, flake-parts, ... }:
-    let
-      lib = nixpkgs.lib.extend(_: lib:
-        import ./lib { inherit lib; }
-      );
-
-    in flake-parts.lib.mkFlake {
-      inherit inputs;
-      specialArgs = { inherit lib; };
-    } {
+    flake-parts.lib.mkFlake { inherit inputs; } {
       systems = [ "x86_64-linux" ];
       imports = [ ./modules ];
-      flake = { inherit lib; };
     };
 }
diff --git a/lib/default.nix b/lib/default.nix
diff --git a/modules/common/nix-snapshotter-lib.nix b/modules/common/nix-snapshotter-lib.nix
@@ -96,6 +96,19 @@ let
   # home-manager modules, the easiest transformation is home-manager -> NixOS,
   # which is why the services are written as such.
 
+  # Converts a home-manager systemd user service to a NixOS systemd user
+  # service. Since home-manager style services map closer to raw systemd
+  # service specification, it's easier to transform in this direction.
+  convertServiceToNixOS = unit:
+    {
+      serviceConfig = lib.optionalAttrs (unit?Service) unit.Service;
+      unitConfig = lib.optionalAttrs (unit?Unit) unit.Unit;
+    } // (lib.optionalAttrs (unit?Install.WantedBy) {
+      # Only `WantedBy` is supported by NixOS as [Install] fields are not
+      # supported, due to its stateful nature.
+      wantedBy = unit.Install.WantedBy;
+    });
+
   mkNixSnapshotterService = {
     Service = {
       Type = "notify";
@@ -172,6 +185,7 @@ in {
       default = {
         inherit options;
         inherit settingsFormat;
+        inherit convertServiceToNixOS;
         inherit mkContainerdSettings;
         inherit mkNixSnapshotterService;
         inherit mkRootlessNixSnapshotterService;

diff --git a/modules/nixos/containerd-rootless.nix b/modules/nixos/containerd-rootless.nix
@@ -1,11 +1,9 @@
 { config, lib, ... }:
 let
-  inherit (lib.home-manager)
-    convertServiceToNixOS
-  ;
-
   cfg = config.virtualisation.containerd.rootless;
 
+  ns-lib = config.services.nix-snapshotter.lib;
+
   proxyEnv = config.networking.proxy.envVars;
 
 in {
@@ -19,7 +17,7 @@ in {
     '';
 
     systemd.user.services.containerd = lib.recursiveUpdate
-      (convertServiceToNixOS (cfg.lib.mkRootlessContainerdService cfg))
+      (ns-lib.convertServiceToNixOS (cfg.lib.mkRootlessContainerdService cfg))
       { environment = proxyEnv; };
   };
 }
diff --git a/modules/nixos/nix-snapshotter-rootless.nix b/modules/nixos/nix-snapshotter-rootless.nix
@@ -1,9 +1,5 @@
 { config, lib, ... }:
 let
-  inherit (lib.home-manager)
-    convertServiceToNixOS
-  ;
-
   cfg = config.services.nix-snapshotter.rootless;
 
   ns-lib = config.services.nix-snapshotter.lib;
@@ -29,12 +25,12 @@ in {
         '');
 
       systemd.user.services.nix-snapshotter = lib.recursiveUpdate
-        (convertServiceToNixOS (ns-lib.mkRootlessNixSnapshotterService cfg))
+        (ns-lib.convertServiceToNixOS (ns-lib.mkRootlessNixSnapshotterService cfg))
         { inherit (cfg) path; };
     }
     {
       systemd.user.services.preload-containerd-images = lib.recursiveUpdate
-        (convertServiceToNixOS (ns-lib.mkRootlessPreloadContainerdImageService cfg))
+        (ns-lib.convertServiceToNixOS (ns-lib.mkRootlessPreloadContainerdImageService cfg))
         { environment.CONTAINERD_ADDRESS = "%t/containerd/containerd.sock"; };
     }
   ]);

diff --git a/modules/nixos/nix-snapshotter.nix b/modules/nixos/nix-snapshotter.nix
@@ -6,10 +6,6 @@ let
     types
   ;
 
-  inherit (lib.home-manager)
-    convertServiceToNixOS
-  ;
-
   cfg = config.services.nix-snapshotter;
 
   ns-lib = cfg.lib;
@@ -57,7 +53,7 @@ in {
       };
 
       systemd.services.nix-snapshotter = lib.recursiveUpdate
-        (convertServiceToNixOS ns-lib.mkNixSnapshotterService)
+        (ns-lib.convertServiceToNixOS ns-lib.mkNixSnapshotterService)
         {
           inherit (cfg) path;
           description = "nix-snapshotter - containerd snapshotter that understands nix store paths natively";
@@ -69,7 +65,7 @@ in {
     }
     (lib.mkIf (cfg.preloadContainerdImages != []) {
       systemd.services.preload-containerd-images = lib.recursiveUpdate
-        (convertServiceToNixOS (ns-lib.mkPreloadContainerdImageService cfg))
+        (ns-lib.convertServiceToNixOS (ns-lib.mkPreloadContainerdImageService cfg))
         {
           description = "Preload images to containerd";
           wantedBy = [ "multi-user.target" ];