Merge pull request #240 from DavHau/improvements

.github/workflows/build.yml

@@ -16,5 +16,5 @@ jobs:
     - uses: cachix/install-nix-action@v21
     - name: List flake structure
       run: nix flake show
-    - name: Run unit tests (flake)
-      run: nix build -L
+    - name: Run tests
+      run: nix flake check -L

checks/is-formatted.nix

@@ -0,0 +1,5 @@
+{pkgs ? import <nixpkgs> {}}:
+pkgs.runCommand "check-format" {} ''
+  ${pkgs.alejandra}/bin/alejandra -c ${./.}
+  touch $out
+''

configuration.nix

@@ -1,10 +1,14 @@
-{ config, lib, pkgs, ... }:
 {
+  config,
+  lib,
+  pkgs,
+  ...
+}: {
   services.sshd.enable = true;
   services.nginx.enable = true;
 
-  networking.firewall.allowedTCPPorts = [ 80 ];
-  
+  networking.firewall.allowedTCPPorts = [80];
+
   users.users.root.password = "nixos";
   services.openssh.permitRootLogin = lib.mkDefault "yes";
   services.getty.autologinUser = lib.mkDefault "root";

default.nix

@@ -1,3 +1,5 @@
 (import (builtins.fetchTarball https://github.com/edolstra/flake-compat/archive/master.tar.gz) {
   src = ./.;
-}).defaultNix.default
+})
+.defaultNix
+.default

flake.nix

@@ -7,108 +7,145 @@
   # Bin dependency
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
 
-  outputs = { self, nixpkgs, nixlib }:
-
+  outputs = {
+    self,
+    nixpkgs,
+    nixlib,
+  }:
   # Library modules (depend on nixlib)
-  {
-    # export all generator formats in ./formats
-    nixosModules = nixlib.lib.mapAttrs' (file: _: {
-      name = nixlib.lib.removeSuffix ".nix" file;
-      # The exported module should include the internal format* options
-      value.imports = [ (./formats + "/${file}") ./format-module.nix ];
-    }) (builtins.readDir ./formats);
+    {
+      # export all generator formats in ./formats
+      nixosModules = nixlib.lib.mapAttrs' (file: _: {
+        name = nixlib.lib.removeSuffix ".nix" file;
+        # The exported module should include the internal format* options
+        value.imports = [(./formats + "/${file}") ./format-module.nix];
+      }) (builtins.readDir ./formats);
 
-    # example usage in flakes:
-    #   outputs = { self, nixpkgs, nixos-generators, ...}: {
-    #     vmware = nixos-generators.nixosGenerate {
-    #       system = "x86_64-linux";
-    #       modules = [./configuration.nix];
-    #       format = "vmware";
-    #   };
-    # }
+      # example usage in flakes:
+      #   outputs = { self, nixpkgs, nixos-generators, ...}: {
+      #     vmware = nixos-generators.nixosGenerate {
+      #       system = "x86_64-linux";
+      #       modules = [./configuration.nix];
+      #       format = "vmware";
+      #   };
+      # }
 
-    nixosGenerate = { pkgs ? null, lib ? nixpkgs.lib, format, system ? null, specialArgs ? { }, modules ? [ ], customFormats ? {} }:
-    let 
-      extraFormats = lib.mapAttrs' (name: value: lib.nameValuePair 
-        (name) 
-        (value // { 
-          imports = ( value.imports or [] ++ [ ./format-module.nix ] ); 
-        } )
-        ) customFormats;
-      formatModule = builtins.getAttr format (self.nixosModules // extraFormats);
-      image = nixpkgs.lib.nixosSystem {
-        inherit pkgs specialArgs;
-        system = if system != null then system else pkgs.system;
-        lib = if lib != null then lib else pkgs.lib;
-        modules = [
-          formatModule
-        ] ++ modules;
-      };
-    in
-      image.config.system.build.${image.config.formatAttr};
-
-  }
-
-  //
-
-
-  # Binary and Devshell outputs (depend on nixpkgs)
-  (
-    let
-       forAllSystems = nixpkgs.lib.genAttrs [ "x86_64-linux" "x86_64-darwin" "i686-linux" "aarch64-linux" "aarch64-darwin" ];
-    in {
-
-      packages = forAllSystems (system: let
-        pkgs = nixpkgs.legacyPackages."${system}";
-      in rec {
-        nixos-generators = nixpkgs.lib.warn ''
-
-          Deprecation note from: github:nix-community/nixos-generators
-
-          Was renamed:
-
-          Was: nixos-generators.packages.${system}.nixos-generators
-          Now: nixos-generators.packages.${system}.nixos-generate
-
-          Plase adapt your references
-        '' nixos-generate;
-        nixos-generate = pkgs.stdenv.mkDerivation {
-          name = "nixos-generate";
-          src = ./.;
-          meta.description = "Collection of image builders";
-          nativeBuildInputs = with pkgs; [ makeWrapper ];
-          installFlags = [ "PREFIX=$(out)" ];
-          postFixup = ''
-            wrapProgram $out/bin/nixos-generate \
-              --prefix PATH : ${pkgs.lib.makeBinPath (with pkgs; [ jq coreutils findutils ])}
-          '';
+      nixosGenerate = {
+        pkgs ? null,
+        lib ? nixpkgs.lib,
+        format,
+        system ? null,
+        specialArgs ? {},
+        modules ? [],
+        customFormats ? {},
+      }: let
+        extraFormats =
+          lib.mapAttrs' (
+            name: value:
+              lib.nameValuePair
+              name
+              (value
+                // {
+                  imports = value.imports or [] ++ [./format-module.nix];
+                })
+          )
+          customFormats;
+        formatModule = builtins.getAttr format (self.nixosModules // extraFormats);
+        image = nixpkgs.lib.nixosSystem {
+          inherit pkgs specialArgs;
+          system =
+            if system != null
+            then system
+            else pkgs.system;
+          lib =
+            if lib != null
+            then lib
+            else pkgs.lib;
+          modules =
+            [
+              formatModule
+            ]
+            ++ modules;
         };
-      });
-
-      defaultPackage = forAllSystems (system: self.packages."${system}".nixos-generate);
-
-      devShell = forAllSystems (system: let
-        pkgs = nixpkgs.legacyPackages."${system}";
-      in pkgs.mkShell {
-        buildInputs = with pkgs; [ jq coreutils findutils ];
-      });
-
-      # Make it runnable with `nix run`
-      apps = forAllSystems (system: let
-        nixos-generate = {
-          type    = "app";
-          program = "${self.packages."${system}".nixos-generate}/bin/nixos-generate";
-        };
-      in {
-        inherit nixos-generate;
-
-        # Nix >= 2.7 flake output schema uses `apps.<system>.default` instead
-        # of `defaultApp.<system>` to signify the default app (the thing that
-        # gets run with `nix run . -- <args>`)
-        default = nixos-generate;
-      });
-
-      defaultApp = forAllSystems (system: self.apps."${system}".nixos-generate);
+      in
+        image.config.system.build.${image.config.formatAttr};
     }
-  );
+    //
+    # Binary and Devshell outputs (depend on nixpkgs)
+    (
+      let
+        forAllSystems = nixpkgs.lib.genAttrs ["x86_64-linux" "x86_64-darwin" "i686-linux" "aarch64-linux" "aarch64-darwin"];
+      in {
+        formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.alejandra);
+
+        packages = forAllSystems (system: let
+          pkgs = nixpkgs.legacyPackages."${system}";
+        in rec {
+          default = nixos-generate;
+          nixos-generators =
+            nixpkgs.lib.warn ''
+
+              Deprecation note from: github:nix-community/nixos-generators
+
+              Was renamed:
+
+              Was: nixos-generators.packages.${system}.nixos-generators
+              Now: nixos-generators.packages.${system}.nixos-generate
+
+              Plase adapt your references
+            ''
+            nixos-generate;
+          nixos-generate = pkgs.stdenv.mkDerivation {
+            name = "nixos-generate";
+            src = ./.;
+            meta.description = "Collection of image builders";
+            nativeBuildInputs = with pkgs; [makeWrapper];
+            installFlags = ["PREFIX=$(out)"];
+            postFixup = ''
+              wrapProgram $out/bin/nixos-generate \
+                --prefix PATH : ${pkgs.lib.makeBinPath (with pkgs; [jq coreutils findutils])}
+            '';
+          };
+        });
+
+        checks = forAllSystems (system: {
+          inherit
+            (self.packages.${system})
+            nixos-generate
+            ;
+          is-formatted = import ./checks/is-formatted.nix {
+            pkgs = nixpkgs.legacyPackages.${system};
+          };
+        });
+
+        devShells = forAllSystems (system: let
+          pkgs = nixpkgs.legacyPackages."${system}";
+        in {
+          default = pkgs.mkShell {
+            buildInputs = with pkgs; [jq coreutils findutils];
+          };
+        });
+
+        # Make it runnable with `nix run`
+        apps = forAllSystems (system: let
+          nixos-generate = {
+            type = "app";
+            program = "${self.packages."${system}".nixos-generate}/bin/nixos-generate";
+          };
+        in {
+          inherit nixos-generate;
+
+          # Nix >= 2.7 flake output schema uses `apps.<system>.default` instead
+          # of `defaultApp.<system>` to signify the default app (the thing that
+          # gets run with `nix run . -- <args>`)
+          default = nixos-generate;
+        });
+
+        # legacy flake schema compat
+        defaultApp = forAllSystems (system: self.apps."${system}".nixos-generate);
+        defaultPackage =
+          forAllSystems (system: self.packages.${system}.default);
+        devShell = forAllSystems (system: self.devShells.${system}.default);
+      }
+    );
 }

format-module.nix

@@ -1,4 +1,4 @@
-{ lib, ... }: rec {
+{lib, ...}: rec {
   _file = ./format-module.nix;
   # This deliberate key makes sure this module will be deduplicated
   # regardless of the accessor path: either via flake's nixosModule
@@ -18,4 +18,3 @@
     };
   };
 }
-

formats/amazon.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/../maintainers/scripts/ec2/amazon-image.nix"
   ];

formats/azure.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/azure-image.nix"
   ];

formats/cloudstack.nix

@@ -1,14 +1,20 @@
-{ config, lib, pkgs, modulesPath, ... }:
 {
+  config,
+  lib,
+  pkgs,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/virtualisation/cloudstack-config.nix"
   ];
 
-  system.build.cloudstackImage =  import "${toString modulesPath}/../lib/make-disk-image.nix" {
+  system.build.cloudstackImage = import "${toString modulesPath}/../lib/make-disk-image.nix" {
     inherit lib config pkgs;
     diskSize = 8192;
     format = "qcow2";
-    configFile = pkgs.writeText "configuration.nix"
+    configFile =
+      pkgs.writeText "configuration.nix"
       ''
         {
           imports = [ "${toString modulesPath}/virtualisation/cloudstack-config.nix" ];

formats/do.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/digital-ocean-image.nix"
   ];

formats/docker.nix

@@ -1,5 +1,8 @@
-{ modulesPath, lib, ... }:
 {
+  modulesPath,
+  lib,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/virtualisation/docker-image.nix"
   ];

formats/gce.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/google-compute-image.nix"
   ];

formats/hyperv.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/hyperv-image.nix"
   ];

formats/install-iso-hyperv.nix

@@ -1,11 +1,15 @@
-{ config, lib, modulesPath, ... }:
 {
+  config,
+  lib,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/installer/cd-dvd/installation-cd-base.nix"
   ];
 
   # override installation-cd-base and enable wpa and sshd start at boot
-  systemd.services.sshd.wantedBy = lib.mkForce [ "multi-user.target" ];
+  systemd.services.sshd.wantedBy = lib.mkForce ["multi-user.target"];
   virtualisation.hypervGuest.enable = true;
 
   formatAttr = "isoImage";

formats/install-iso.nix

@@ -1,12 +1,16 @@
-{ config, lib, modulesPath, ... }:
 {
+  config,
+  lib,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/installer/cd-dvd/installation-cd-base.nix"
   ];
 
   # override installation-cd-base and enable wpa and sshd start at boot
-  systemd.services.wpa_supplicant.wantedBy = lib.mkForce [ "multi-user.target" ];
-  systemd.services.sshd.wantedBy = lib.mkForce [ "multi-user.target" ];
+  systemd.services.wpa_supplicant.wantedBy = lib.mkForce ["multi-user.target"];
+  systemd.services.sshd.wantedBy = lib.mkForce ["multi-user.target"];
 
   formatAttr = "isoImage";
   filename = "*.iso";

formats/iso.nix

@@ -1,5 +1,8 @@
-{ config, modulesPath, ... }:
 {
+  config,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/installer/cd-dvd/iso-image.nix"
   ];

formats/kexec-bundle.nix

@@ -1,6 +1,5 @@
-{ lib, ... }:
-{
-  imports = [ ./kexec.nix ];
+{lib, ...}: {
+  imports = [./kexec.nix];
 
   formatAttr = lib.mkForce "kexec_bundle";
   filename = lib.mkForce "*-kexec_bundle";

formats/kexec.nix

@@ -1,11 +1,17 @@
-{ config, pkgs, lib, modulesPath, options, ... }: let
-
+{
+  config,
+  pkgs,
+  lib,
+  modulesPath,
+  options,
+  ...
+}: let
   clever-tests = builtins.fetchGit {
     url = "https://github.com/cleverca22/nix-tests";
     rev = "a9a316ad89bfd791df4953c1a8b4e8ed77995a18"; # master on 2021-06-13
   };
 
-  inherit (import ../lib.nix { inherit lib options; }) maybe;
+  inherit (import ../lib.nix {inherit lib options;}) maybe;
 in {
   imports = [
     "${toString modulesPath}/installer/netboot/netboot-minimal.nix"
@@ -17,7 +23,10 @@ in {
   system.build = rec {
     kexec_tarball = maybe.mkForce (pkgs.callPackage "${toString modulesPath}/../lib/make-system-tarball.nix" {
       storeContents = [
-        { object = config.system.build.kexec_script; symlink = "/kexec_nixos"; }
+        {
+          object = config.system.build.kexec_script;
+          symlink = "/kexec_nixos";
+        }
       ];
       contents = [];
     });
@@ -50,10 +59,11 @@ in {
 
   boot.loader.grub.enable = false;
   boot.kernelParams = [
-    "console=ttyS0,115200"          # allows certain forms of remote access, if the hardware is setup right
-    "panic=30" "boot.panic_on_fail" # reboot the machine upon fatal boot issues
+    "console=ttyS0,115200" # allows certain forms of remote access, if the hardware is setup right
+    "panic=30"
+    "boot.panic_on_fail" # reboot the machine upon fatal boot issues
   ];
-  systemd.services.sshd.wantedBy = lib.mkForce [ "multi-user.target" ];
+  systemd.services.sshd.wantedBy = lib.mkForce ["multi-user.target"];
   networking.hostName = lib.mkDefault "kexec";
 
   formatAttr = "kexec_tarball";

formats/kubevirt.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/kubevirt.nix"
   ];

formats/linode.nix

@@ -1,5 +1,10 @@
-{ config, lib, pkgs, modulesPath, ... }:
 {
+  config,
+  lib,
+  pkgs,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/profiles/qemu-guest.nix"
   ];
@@ -23,7 +28,7 @@
     autoResize = true;
   };
 
-  swapDevices = [{ device = "/dev/sdb"; }];
+  swapDevices = [{device = "/dev/sdb";}];
 
   # Enable LISH and Linode booting w/ GRUB
   boot = {
@@ -38,7 +43,7 @@
     growPartition = true;
 
     # Set up LISH serial connection:
-    kernelParams = [ "console=ttyS0,19200n8" ];
+    kernelParams = ["console=ttyS0,19200n8"];
 
     loader = {
       # Increase timeout to allow LISH connection:

formats/lxc-metadata.nix

@@ -1,6 +1,9 @@
-{ config, pkgs, modulesPath, ... }:
-
 {
+  config,
+  pkgs,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/virtualisation/lxc-container.nix"
   ];
@@ -8,4 +11,3 @@
   formatAttr = "metadata";
   filename = "*/tarball/*.tar.xz";
 }
-

formats/lxc.nix

@@ -1,6 +1,10 @@
-{ config, pkgs, lib, modulesPath, ... }:
-
 {
+  config,
+  pkgs,
+  lib,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/virtualisation/lxc-container.nix"
   ];

formats/openstack.nix

@@ -1,11 +1,17 @@
-{ modulesPath, lib, ... }:
-if lib.pathExists "${toString modulesPath}/../maintainers/scripts/openstack/nova-image.nix" then {
+{
+  modulesPath,
+  lib,
+  ...
+}:
+if lib.pathExists "${toString modulesPath}/../maintainers/scripts/openstack/nova-image.nix"
+then {
   imports = [
     "${toString modulesPath}/../maintainers/scripts/openstack/nova-image.nix"
   ];
 
   formatAttr = "novaImage";
-} else {
+}
+else {
   imports = [
     "${toString modulesPath}/../maintainers/scripts/openstack/openstack-image.nix"
   ];

formats/proxmox-lxc.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/proxmox-lxc.nix"
   ];

formats/proxmox.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/proxmox-image.nix"
   ];

formats/qcow.nix

@@ -1,5 +1,10 @@
-{ config, lib, pkgs, modulesPath, ... }:
 {
+  config,
+  lib,
+  pkgs,
+  modulesPath,
+  ...
+}: {
   # for virtio kernel drivers
   imports = [
     "${toString modulesPath}/profiles/qemu-guest.nix"
@@ -12,17 +17,16 @@
   };
 
   boot.growPartition = true;
-  boot.kernelParams = [ "console=ttyS0" ];
-  boot.loader.grub.device = if (pkgs.stdenv.system == "x86_64-linux") then
-    (lib.mkDefault "/dev/vda")
-  else
-    (lib.mkDefault "nodev");
+  boot.kernelParams = ["console=ttyS0"];
+  boot.loader.grub.device =
+    if (pkgs.stdenv.system == "x86_64-linux")
+    then (lib.mkDefault "/dev/vda")
+    else (lib.mkDefault "nodev");
 
   boot.loader.grub.efiSupport = lib.mkIf (pkgs.stdenv.system != "x86_64-linux") (lib.mkDefault true);
   boot.loader.grub.efiInstallAsRemovable = lib.mkIf (pkgs.stdenv.system != "x86_64-linux") (lib.mkDefault true);
   boot.loader.timeout = 0;
 
-
   system.build.qcow = import "${toString modulesPath}/../lib/make-disk-image.nix" {
     inherit lib config pkgs;
     diskSize = 8192;

formats/raw-efi.nix

@@ -1,9 +1,14 @@
-{ config, lib, options, pkgs, modulesPath, ... }:
-
-let
-  inherit (import ../lib.nix { inherit lib options; }) maybe;
+{
+  config,
+  lib,
+  options,
+  pkgs,
+  modulesPath,
+  ...
+}: let
+  inherit (import ../lib.nix {inherit lib options;}) maybe;
 in {
-  imports = [ ./raw.nix ];
+  imports = [./raw.nix];
 
   boot.loader.grub = {
     device = "nodev";

formats/raw.nix

@@ -1,5 +1,10 @@
-{ config, lib, pkgs, modulesPath, ... }:
 {
+  config,
+  lib,
+  pkgs,
+  modulesPath,
+  ...
+}: {
   fileSystems."/" = {
     device = "/dev/disk/by-label/nixos";
     autoResize = true;
@@ -8,13 +13,12 @@
 
   boot = {
     growPartition = true;
-    kernelParams = [ "console=ttyS0" ];
+    kernelParams = ["console=ttyS0"];
     loader.grub.device = lib.mkDefault "/dev/vda";
     loader.timeout = lib.mkDefault 0;
-    initrd.availableKernelModules = [ "uas" ];
+    initrd.availableKernelModules = ["uas"];
   };
 
-
   system.build.raw = import "${toString modulesPath}/../lib/make-disk-image.nix" {
     inherit lib config pkgs;
     diskSize = "auto";

formats/sd-aarch64-installer.nix

@@ -1,5 +1,8 @@
-{ config, modulesPath, ... }:
 {
+  config,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/installer/sd-card/sd-image-aarch64-installer.nix"
   ];

formats/sd-aarch64.nix

@@ -1,5 +1,10 @@
-{ config, lib, pkgs, modulesPath, ... }:
 {
+  config,
+  lib,
+  pkgs,
+  modulesPath,
+  ...
+}: {
   imports = [
     "${toString modulesPath}/installer/sd-card/sd-image-aarch64.nix"
   ];

formats/vagrant-virtualbox.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/vagrant-virtualbox-image.nix"
   ];

formats/virtualbox.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/virtualbox-image.nix"
   ];

formats/vm-bootloader.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     ./vm.nix
   ];

formats/vm-nogui.nix

@@ -1,5 +1,4 @@
-{ pkgs, ... }:
-let
+{pkgs, ...}: let
   resize = pkgs.writeScriptBin "resize" ''
     if [ -e /dev/tty ]; then
       old=$(stty -g)
@@ -15,8 +14,8 @@ in {
     ./vm.nix
   ];
   virtualisation.graphics = false;
-  virtualisation.qemu.options = [ "-serial mon:stdio" ];
+  virtualisation.qemu.options = ["-serial mon:stdio"];
 
-  environment.systemPackages = [ resize ];
+  environment.systemPackages = [resize];
   environment.loginShellInit = "${resize}/bin/resize";
 }

formats/vm.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/qemu-vm.nix"
   ];

formats/vmware.nix

@@ -1,5 +1,4 @@
-{ modulesPath, ... }:
-{
+{modulesPath, ...}: {
   imports = [
     "${toString modulesPath}/virtualisation/vmware-image.nix"
   ];

nixos-generate.nix

@@ -1,22 +1,21 @@
-{ nixpkgs ? <nixpkgs>
-, configuration ? <nixos-config>
-, system ? builtins.currentSystem
-
-, formatConfig
-
-, flakeUri ? null
-, flakeAttr ? null
-}:
-let
+{
+  nixpkgs ? <nixpkgs>,
+  configuration ? <nixos-config>,
+  system ? builtins.currentSystem,
+  formatConfig,
+  flakeUri ? null,
+  flakeAttr ? null,
+}: let
   module = import ./format-module.nix;
 
   # Will only get evaluated when used, so no worries
   flake = builtins.getFlake flakeUri;
   flakeSystem = flake.outputs.packages."${system}".nixosConfigurations."${flakeAttr}" or flake.outputs.nixosConfigurations."${flakeAttr}";
 in
-  if flakeUri != null then
+  if flakeUri != null
+  then
     flakeSystem.extendModules {
-      modules = [ module formatConfig ];
+      modules = [module formatConfig];
     }
   else
     import "${toString nixpkgs}/nixos/lib/eval-config.nix" {

shell.nix

@@ -1,3 +1,5 @@
 (import (builtins.fetchTarball https://github.com/edolstra/flake-compat/archive/master.tar.gz) {
   src = ./.;
-}).shellNix.default
+})
+.shellNix
+.default