# API Guide ## lib This section covers important functions available in Flakelight's lib attribute. ### mkFlake The outputs of a flake using Flakelight are created using the `mkFlake` function. When called directly, Flakelight invokes `mkFlake`, as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { # Your flake configuration here }; } ``` To call `mkFlake` explicitly, you can do: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight.lib.mkFlake ./. { # Your flake configuration here }; } ``` `mkFlake` takes two parameters: the path to the flake's source and a Flakelight module. If you need access to module args, you can write it as bellow: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. ({ lib, config, ... }: { # Your flake configuration here }); } ``` ## Module arguments The following module arguments are available: - `src`: The flake's source directory - `lib`: nixpkgs lib attribute - `config`: configured option values - `options`: available options - `flakelight`: flakelight lib attribute - `inputs`: value of inputs option - `outputs`: resulting output (i.e. final flake attributes) - `autoloadArgs`: arguments passed to supported autoloaded files ## Additional pkgs values Functions that take the package set as an argument, such as package definitions or `perSystem` values, have several additional values available in the package set. The `src`, `inputs`, `outputs`, and `flakelight` attributes are the same as the above module arguments. `inputs'` and `outputs'` are transformed versions of `inputs` and `outputs` with system preselected. I.e., `inputs.emacs-overlay.packages.x86_64-linux.default` can be accessed as `inputs'.emacs-overlay.packages.default`. `defaultMeta` is a derivation meta attribute set generated from options. Modules setting `packages.default` should use this to allow meta attributes to be configured. ## Module options This section covers the options available to modules. ### inputs The `inputs` option allows setting the flake inputs used by modules. To set the nixpkgs used for building outputs, you can pass your flake inputs in as follows: ```nix { inputs = { nixpkgs.url = "nixpkgs/nixpkgs-unstable"; flakelight.url = "github:accelbread/flakelight"; }; outputs = { flakelight, ... }@inputs: flakelight ./. { inherit inputs; }; } ``` Or to just pass just the nixpkgs input: ```nix { inputs = { nixpkgs.url = "nixpkgs/nixpkgs-unstable"; flakelight.url = "github:accelbread/flakelight"; }; outputs = { flakelight, nixpkgs, ... }: flakelight ./. { inputs.nixpkgs = nixpkgs; }; } ``` ### systems The `systems` option sets which systems per-system outputs should be created for. If not set, the default is `x86_64-linux` and `aarch64-linux`. To also support `i686-linux` and `armv7l-linux`, you would configure `systems` as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { systems = [ "x86_64-linux" "aarch64-linux" "i686-linux" "armv7l-linux" ]; }; } ``` To support all systems supported by flakes, set `systems` as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. ({ lib, ... }: { systems = lib.systems.flakeExposed; }); } ``` To support all Linux systems supported by flakes, set `systems` as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. ({ lib, ... }: { systems = lib.intersectLists lib.systems.doubles.linux lib.systems.flakeExposed; }); } ``` ### outputs The `outputs` option allows you to directly configure flake outputs. This should be used for porting or for configuring output attrs not otherwise supported by Flakelight. To add a `example.test` output to your flake you could do the following: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { outputs = { example.test = "hello"; }; }; } ``` With the above, `nix eval .#example.test` will ouput "hello". This can be used to configure any output, for example directly setting an overlay (though this can be configured with the `overlays` option): ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { outputs.overlays.clang = final: prev: { stdenv = final.clangStdenv; }; }; } ``` ### perSystem The `perSystem` option allows you to directly configure per-system flake outputs, and gives you access to packages. This should be used for porting or for configuring output attrs not otherwise supported by Flakelight. To add `example.${system}.test` outputs to your flake, you could do the following: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { perSystem = pkgs: { example.test = pkgs.writeShellScript "test" "echo hello"; }; }; } ``` The above, with default systems, will generate `example.x86-64_linux.test` and `example.aarch64-linux.test` attributes. ### nixpkgs.config This allows you to pass configuration options to the nixpkgs instance used for building packages and calling perSystem. For example, to allow building broken or unsupported packages, you can set the option as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { nixpkgs.config = { allowBroken = true; allowUnsupportedSystem = true; }; }; } ``` ### withOverlays This allows you to apply overlays to the nixpkgs instance used for building packages and calling perSystem. It can be set to either a list of overlays or a single overlay. For example, to apply the Emacs overlay and change the Zig version, you can set the option as follows: ```nix { inputs = { flakelight.url = "github:accelbread/flakelight"; emacs-overlay.url = "github:nix-community/emacs-overlay"; }; outputs = { flakelight, emacs-overlay, ... }: flakelight ./. { withOverlays = [ emacs-overlay.overlays.default (final: prev: { zig = final.zig_0_9; }) ]; }; } ``` You can use the values from the overlays with other options: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { withOverlays = final: prev: { testValue = "hi"; }; package = { writeShellScript, testValue }: writeShellScript "test" "echo ${testValue}"; }; } ``` ### packages The `package` and `packages` options allow you to add packages. These are exported in the `packages.${system}` ouputs, are included in `overlays.default`, and have build checks in `checks.${system}`. `package` can be set to a package definition, and will set `packages.default`. `packages` can be set to attrs of package definitions. To set the default package, you can set the options as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { package = { stdenv }: stdenv.mkDerivation { pname = "pkg1"; version = "0.0.1"; src = ./.; installPhase = "make DESTDIR=$out install"; }; }; } ``` The above will export `packages.${system}.default` attributes, add `pkg1` to `overlays.default`, and export `checks.${system}.packages-default`. To set multiple packages, you can set the options as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { packages = { default = { stdenv }: stdenv.mkDerivation { name = "pkg1"; src = ./.; installPhase = "make DESTDIR=$out install"; }; pkg2 = { stdenv, pkg1, pkg3 }: { stdenv.mkDerivation { name = "hello-world"; src = ./pkg2; nativeBuildInputs = [ pkg1 pkg3 ]; installPhase = "make DESTDIR=$out install"; }; pkg3 = { stdenv }: { stdenv.mkDerivation { name = "hello-world"; src = ./pkg3; installPhase = "make DESTDIR=$out install"; }; }; }; }; } ``` You can also instead just directly set `packages.default` The above will export `packages.${system}.default`, `packages.${system}.pkg2`, `packages.${system}.pkg3` attributes, add `pkg1`, `pkg2`, and `pkg3` to `overlays.default`, and export corresponding build checks. ### devShell The devshell options allow you to configure `devShells.${system}.default`. It is split up into options in order to enable multiple modules to contribute to its configuration. The first three correspond to `mkShell` arguments. `devShell.packages` is a function that takes the package set and returns a list of packages to add to the shell. `devShell.inputsFrom` is a function that takes the package set and returns a list of packages whose deps should be in the shell. `devShell.shellHook` is a string that provides bash code to run in shell initialization. It can optionally be a function to such a string in order to access packages. `devShell.env` is for setting environment variables in the shell. It is an attribute set mapping variables to values. It can optionally be a function to such an attribute set in order to access packages. For example, these can be configured as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { devShell = { # Include build deps of emacs inputsFrom = pkgs: [ pkgs.emacs ]; # Add coreutils to the shell packages = pkgs: [ pkgs.coreutils ]; # Add shell hook. Can be a function if you need packages shellHook = '' echo Welcome to example shell! ''; # Set an environment var. `env` can be an be a function env.TEST_VAR = "test value"; }; }; } ``` The above exports `devShells.${system}.default` outputs. To add build inputs of one of your packages, you can do as follows: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { package = { stdenv }: stdenv.mkDerivation { pname = "pkg1"; version = "0.0.1"; src = ./.; installPhase = "make DESTDIR=$out install"; }; devShell = { inputsFrom = pkgs: [ pkgs.pkg1 ]; }; }; } ``` ### devShells The `devShells` option allows you to set additional `devShell` outputs. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { devShells.testing = { mkShell, coreutils }: mkShell { packages = [ coreutils ]; env.TEST_VAR = "in testing shell"; }; }; } ``` The above exports `devShells.${system}.testing` outputs. ### overlays The `overlay` and `overlays` options allow you to configure `overlays` outputs. Multiple provided overlays for an output are merged. The `overlay` option adds the overlay to `overlays.default`. The `overlays` option allows you to add overlays to `overlays` outputs. For example, to add an overlay to `overlays.default`, do the following: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { overlay = final: prev: { testValue = "hello"; }; }; } ``` The above results in `overlays.default` output containing testValue. To configure other overlays: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { overlays.cool = final: prev: { testValue = "cool"; }; }; } ``` The above results in a `overlays.cool` output. ### checks The `checks` option allows you to add checks for `checks.${system}` attributes. It can be set to an attribute set of checks, which can be functions, derivations, or strings. If a check is a derivation, it will be used as is. If a check is a string, it will be included in a bash script that runs it in a copy of the source directory, and succeeds if the no command in the string errored. If a check is a function, it will be passed packages, and should return one of the above. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { checks = { # Check that succeeds if the source contains the string "hi" hi = { rg, ... }: "${rg}/bin/rg hi"; # Check that emacs builds emacs = pkgs: pkgs.emacs; }; }; } ``` ### apps The `app` and `apps` options allow you to set `apps.${system}` outputs. `apps` is an attribute set of apps or a function that takes packages and returns an attribute set of apps. If the app value is not an app, it is converted to a string and set as the program attr of an app. If it is a function, it is passed packages. `app` sets `apps.default`. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { apps = { shell = "/bin/sh" emacs = pkgs: "${pkgs.emacs}/bin/emacs"; bash = pkgs: { type = "app"; program = "${pkgs.bash}/bin/bash"; }; }; }; } ``` Alternatively, the above can be written as: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { apps = { emacs, bash, ... }: { shell = "/bin/sh" emacs = "${emacs}/bin/emacs"; bash = { type = "app"; program = "${bash}/bin/bash"; }; }; }; } ``` ### templates The `template` and `templates` options allow you to set `templates.${system}` outputs. `templates` is an attribute set to template values. `template` sets `templates.default`. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { templates.test-template = { path = ./test; description = "test template"; }; }; } ``` ### formatters The `formatters` option allows you to configure formatting tools that will be used by `nix fmt`. If formatters are set, Flakelight will export `formatter.${system}` outputs which apply all the configured formatters. By default, `nix` files are formatted with `nixpkgs-fmt` and `md`, `json`, and `yml` files are formatted with `prettier`. To disable default formatters, set the `flakelight.builtinFormatters` option to false. You can set `formatters` to an attribute set, for which the keys are a file name pattern and the value is the corresponding formatting command. `formatters` can optionally be a function that takes packages and returns the above. Formatting tools should be added to `devShell.packages` and all packages in `devShell.packages` will be available for formatting commands. For example, to set Rust and Zig formatters: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { devShell.packages = pkgs: [ pkgs.rustfmt pkgs.zig ]; formatters = { "*.rs" = "rustfmt"; "*.zig" = "zig fmt"; }; }; } ``` ### nixosConfigurations and homeConfigurations The `nixosConfigurations` and `homeConfigurations` attributes let you set outputs for NixOS systems and home-manager users. They should be set to an attribute set of respective configurations. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. ({ lib, ... }: { nixosConfigurations.system = lib.nixosSystem { # nixosSystem arguments }; }); } ``` ```nix { inputs = { flakelight.url = "github:accelbread/flakelight"; home-manger.url = "github:nix-community/home-manager"; }; outputs = { flakelight, home-manager, ... }: flakelight ./. { homeConfigurations.user = home-manager.lib.homeManagerConfiguration { # homeManagerConfiguration arguments }; }; } ``` ### nixosModules, homeModules, and flakelightModules The `nixosModules`, `homeModules`, and `flakelightModules` options allow you to configure the corresponding outputs. The `nixosModule`, `homeModule`, and `flakelightModule` options set the `default` attribute of the corresponding above option. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. ({ lib, ... }: { nixosModule = { system, lib, pkgs, ... }: { # nixos module configuration }; }); } ``` These can be paths, which is preferred as it results in better debug output: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. ({ lib, ... }: { nixosModule = ./module.nix; homeModules = { default = ./home.nix; emacs = ./emacs.nix; } }); } ``` ### lib The `lib` option allows you to configure the flake's `lib` output. For example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { lib = { addFive = x: x + 5; addFour = x: x + 4; }; }; } ``` ### functor The `functor` option allows you to make your flake callable. If it is set to a function, that function will be set as the `__functor` attribute of your flake outputs. Flakelight uses it so that calling your `flakelight` input calls `flakelight.lib.mkFlake`. As an example: ```nix { inputs.flakelight.url = "github:accelbread/flakelight"; outputs = { flakelight, ... }: flakelight ./. { outputs.testvalue = 5; functor = self: x: x + self.testvalue; } } ``` With the above flake, another flake that has imports it with the name `addFive` would be able to call `addFive 4` to get 9. ### meta The following options are available for configuring the meta attributes of the default package for supported modules (such as flakelight-rust or flakelight-zig) or for use in your own packages through the `defaultMeta` pkgs value. `description` allows setting the package description. `license` lets you set the license or license. It may be a single string or list of strings. These strings may be Spdx license identifiers or nixpkgs license attribute names. ### nixDir The `nixDir` option is `./nix` by default and sets which directory to use to automatically load nix files for flake attributes from. For a given supported attribute attr, the following is checked in order: - If `${nixDir}/attr.nix` exists, it is imported as the value - Else if `${nixDir}/attr` is a directory with a `default.nix`, it is imported - Else if `${nixDir}/attr` is a directory, it results in an attrset with an entry for each nix file in the directory whose values are the corresponding files imported Many of the values can additionally be a function that takes module args to enable use of module args from imported files. The module args available are `lib`, `src`, `inputs`, `outputs`, and `flakelight`. For values without module args, these values can be obtained from pkgs args. To enable using a directory for an attrset that includes a `default` attribute, attr names can be escaped with an underscore. For example, `${nixDir}/nix/packages/_default.nix` will be loaded as `packages.default`. The following options can be autoloaded with optional module args: - outputs - packages - overlays - devShell - devShells - tempalte - templates - nixosModules - nixosConfigurations - homeModules - homeConfigurations - flakelightModules - lib The following options can be autoloaded (no module args): - perSystem - withOverlays - package - app - apps - checks - formatters - nixosModule - homeModule - flakelightModule - functor ### flakelight This option has options for configuring Flakelight's defaults. `flakelight.editorconfig` can be set to false to disable the editorconfig check that is added if editorconfig configuration is detected. `flakelight.builtinFormatters` can be set to false to disable the default formatting configuration.