default.nix

@@ -1,7 +1,8 @@
 {
   lib,
   rustPlatform,
-}: let
+}:
+let
   readToml = path: builtins.fromTOML (builtins.readFile path);
   cargoToml = readToml ./Cargo.toml;
   pname = cargoToml.package.name;
@@ -11,32 +12,34 @@
     name = "${pname}-source";
     # Adapted from <https://github.com/ipetkov/crane/blob/master/lib/filterCargoSources.nix>
     # no need to pull in crane for just this
-    filter = orig_path: type: let
-      path = toString orig_path;
-      base = baseNameOf path;
-      parentDir = baseNameOf (dirOf path);
-      matchesSuffix = lib.any (suffix: lib.hasSuffix suffix base) [
-        # Rust sources
-        ".rs"
-        # TOML files are often used to configure cargo based tools (e.g. .cargo/config.toml)
-        ".toml"
-      ];
-      isCargoLock = base == "Cargo.lock";
-      # .cargo/config.toml is captured above
-      isOldStyleCargoConfig = parentDir == ".cargo" && base == "config";
-    in
+    filter =
+      orig_path: type:
+      let
+        path = toString orig_path;
+        base = baseNameOf path;
+        parentDir = baseNameOf (dirOf path);
+        matchesSuffix = lib.any (suffix: lib.hasSuffix suffix base) [
+          # Rust sources
+          ".rs"
+          # TOML files are often used to configure cargo based tools (e.g. .cargo/config.toml)
+          ".toml"
+        ];
+        isCargoLock = base == "Cargo.lock";
+        # .cargo/config.toml is captured above
+        isOldStyleCargoConfig = parentDir == ".cargo" && base == "config";
+      in
       type == "directory" || matchesSuffix || isCargoLock || isOldStyleCargoConfig;
   };
 in
-  rustPlatform.buildRustPackage {
-    inherit pname version src;
-    cargoLock.lockFile = ./Cargo.lock;
-    useNextest = true;
+rustPlatform.buildRustPackage {
+  inherit pname version src;
+  cargoLock.lockFile = ./Cargo.lock;
+  useNextest = true;
 
-    meta = {
-      inherit description;
-      license = lib.licenses.mit;
-      homepage = "https://github.com/jalil-salame/webnsupdate";
-      mainProgram = "webnsupdate";
-    };
-  }
+  meta = {
+    inherit description;
+    license = lib.licenses.mit;
+    homepage = "https://github.com/jalil-salame/webnsupdate";
+    mainProgram = "webnsupdate";
+  };
+}

flake.nix

@@ -5,59 +5,75 @@
     systems.url = "github:nix-systems/default";
   };
 
-  outputs = {
-    self,
-    nixpkgs,
-    systems,
-  }: let
-    forEachSupportedSystem = nixpkgs.lib.genAttrs (import systems);
-  in {
-    checks = forEachSupportedSystem (system: let
-      pkgs = nixpkgs.legacyPackages.${system};
-      inherit (nixpkgs) lib;
-    in {
-      fmtRust = pkgs.callPackage ./run-cmd.nix {
-        src = self;
-        name = "fmt-rust";
-        extraNativeBuildInputs = [pkgs.rustfmt];
-        cmd = "${lib.getExe pkgs.cargo} fmt --all --check --verbose";
-      };
-      fmtNix = pkgs.callPackage ./run-cmd.nix {
-        src = self;
-        name = "fmt-nix";
-        cmd = "${lib.getExe pkgs.alejandra} --check .";
-      };
-      lintNix = pkgs.callPackage ./run-cmd.nix {
-        src = self;
-        name = "lint-nix";
-        cmd = "${lib.getExe pkgs.statix} check .";
-      };
-    });
-    formatter = forEachSupportedSystem (system: nixpkgs.legacyPackages.${system}.alejandra);
+  outputs =
+    {
+      self,
+      nixpkgs,
+      systems,
+    }:
+    let
+      forEachSupportedSystem = nixpkgs.lib.genAttrs (import systems);
+    in
+    {
+      checks = forEachSupportedSystem (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+          inherit (nixpkgs) lib;
+        in
+        {
+          fmtRust = pkgs.callPackage ./run-cmd.nix {
+            src = self;
+            name = "fmt-rust";
+            extraNativeBuildInputs = [ pkgs.rustfmt ];
+            cmd = "${lib.getExe pkgs.cargo} fmt --all --check --verbose";
+          };
+          fmtNix = pkgs.callPackage ./run-cmd.nix {
+            src = self;
+            name = "fmt-nix";
+            cmd = "${lib.getExe self.formatter.${system}} --check .";
+          };
+          lintNix = pkgs.callPackage ./run-cmd.nix {
+            src = self;
+            name = "lint-nix";
+            cmd = "${lib.getExe pkgs.statix} check .";
+          };
+        }
+      );
+      formatter = forEachSupportedSystem (system: nixpkgs.legacyPackages.${system}.nixfmt-rfc-style);
 
-    packages = forEachSupportedSystem (system: let
-      webnsupdate = nixpkgs.legacyPackages.${system}.callPackage ./default.nix {};
-    in {
-      inherit webnsupdate;
-      default = webnsupdate;
-    });
+      packages = forEachSupportedSystem (
+        system:
+        let
+          webnsupdate = nixpkgs.legacyPackages.${system}.callPackage ./default.nix { };
+        in
+        {
+          inherit webnsupdate;
+          default = webnsupdate;
 
-    overlays.default = final: prev: {
-      webnsupdate = final.callPackage ./default.nix {};
+        }
+      );
+
+      overlays.default = final: prev: {
+        webnsupdate = final.callPackage ./default.nix { };
+      };
+
+      nixosModules.default = ./module.nix;
+
+      devShells = forEachSupportedSystem (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          default = pkgs.mkShell {
+            packages = [
+              pkgs.cargo-insta
+              pkgs.cargo-udeps
+              pkgs.mold
+            ];
+          };
+        }
+      );
     };
-
-    nixosModules.default = ./module.nix;
-
-    devShells = forEachSupportedSystem (system: let
-      pkgs = nixpkgs.legacyPackages.${system};
-    in {
-      default = pkgs.mkShell {
-        packages = [
-          pkgs.cargo-insta
-          pkgs.cargo-udeps
-          pkgs.mold
-        ];
-      };
-    });
-  };
 }

module.nix

@@ -3,13 +3,15 @@
   pkgs,
   config,
   ...
-}: let
+}:
+let
   cfg = config.services.webnsupdate;
   inherit (lib) mkOption mkEnableOption types;
-in {
+in
+{
   options.services.webnsupdate = mkOption {
     description = "An HTTP server for nsupdate.";
-    default = {};
+    default = { };
     type = types.submodule {
       options = {
         enable = mkEnableOption "webnsupdate";
@@ -18,8 +20,8 @@ in {
             Extra arguments to be passed to the webnsupdate server command.
           '';
           type = types.listOf types.str;
-          default = [];
-          example = ["--ip-source"];
+          default = [ ];
+          example = [ "--ip-source" ];
         };
         bindIp = mkOption {
           description = ''
@@ -102,47 +104,53 @@ in {
     };
   };
 
-  config = let
-    recordsFile =
-      if cfg.recordsFile != null
-      then cfg.recordsFile
-      else pkgs.writeText "webnsrecords" cfg.records;
-    args = lib.strings.escapeShellArgs ([
-        "--records"
-        recordsFile
-        "--key-file"
-        cfg.keyFile
-        "--password-file"
-        cfg.passwordFile
-        "--address"
-        cfg.bindIp
-        "--port"
-        (builtins.toString cfg.bindPort)
-        "--ttl"
-        (builtins.toString cfg.ttl)
-      ]
-      ++ cfg.extraArgs);
-    cmd = "${lib.getExe pkgs.webnsupdate} ${args}";
-  in
+  config =
+    let
+      recordsFile =
+        if cfg.recordsFile != null then cfg.recordsFile else pkgs.writeText "webnsrecords" cfg.records;
+      args = lib.strings.escapeShellArgs (
+        [
+          "--records"
+          recordsFile
+          "--key-file"
+          cfg.keyFile
+          "--password-file"
+          cfg.passwordFile
+          "--address"
+          cfg.bindIp
+          "--port"
+          (builtins.toString cfg.bindPort)
+          "--ttl"
+          (builtins.toString cfg.ttl)
+        ]
+        ++ cfg.extraArgs
+      );
+      cmd = "${lib.getExe pkgs.webnsupdate} ${args}";
+    in
     lib.mkIf cfg.enable {
       # warnings =
       #   lib.optional (!config.services.bind.enable) "`webnsupdate` is expected to be used alongside `bind`. This is an unsopported configuration.";
       assertions = [
         {
-          assertion = (cfg.records != null || cfg.recordsFile != null) && !(cfg.records != null && cfg.recordsFile != null);
+          assertion =
+            (cfg.records != null || cfg.recordsFile != null)
+            && !(cfg.records != null && cfg.recordsFile != null);
           message = "Exactly one of `services.webnsupdate.records` and `services.webnsupdate.recordsFile` must be set.";
         }
       ];
 
       systemd.services.webnsupdate = {
         description = "Web interface for nsupdate.";
-        wantedBy = ["multi-user.target"];
-        after = ["network.target" "bind.service"];
+        wantedBy = [ "multi-user.target" ];
+        after = [
+          "network.target"
+          "bind.service"
+        ];
         preStart = "${cmd} verify";
-        path = [pkgs.dig];
+        path = [ pkgs.dig ];
         startLimitIntervalSec = 60;
         serviceConfig = {
-          ExecStart = [cmd];
+          ExecStart = [ cmd ];
           Type = "exec";
           Restart = "on-failure";
           RestartSec = "10s";

run-cmd.nix

@@ -3,8 +3,8 @@
   src,
   name,
   cmd,
-  extraBuildInputs ? [],
-  extraNativeBuildInputs ? [],
+  extraBuildInputs ? [ ],
+  extraNativeBuildInputs ? [ ],
 }:
 stdenvNoCC.mkDerivation {
   name = "${name}-src";