NixOS modules: Difference between revisions
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==== Passing custom values to modules ==== | |||
The [[NixOS:config_argument|<code>config</code>]], <code>options</code>, <code>lib</code>, <code>pkgs</code>, and <code>modulesPath</code> arguments are passed automatically to modules, when the module is imported. | |||
For example, in the following Nix flake, the `./configuration.nix` file will be provided with the default set of arguments listed above, plus `extraArg`, which was set in the `specialArgs` argument to the `nixosGenerate` function.<syntaxhighlight lang="nix"> | |||
{ | |||
inputs = { | |||
nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11"; | |||
nixos-generators = { | |||
url = "github:nix-community/nixos-generators"; | |||
inputs.nixpkgs.follows = "nixpkgs"; | |||
}; | |||
xc = { | |||
url = "github:joerdav/xc"; | |||
inputs.nixpkgs.follows = "nixpkgs"; | |||
}; | |||
}; | |||
outputs = { nixpkgs, nixos-generators, xc, ... }: | |||
let | |||
pkgsForSystem = system: import nixpkgs { | |||
inherit system; | |||
overlays = [ | |||
(final: prev: { xc = xc.packages.${system}.xc; }) | |||
]; | |||
}; | |||
allVMs = [ "x86_64-linux" "aarch64-linux" ]; | |||
forAllVMs = f: nixpkgs.lib.genAttrs allVMs (system: f { | |||
inherit system; | |||
pkgs = pkgsForSystem system; | |||
}); | |||
in | |||
{ | |||
packages = forAllVMs ({ system, pkgs }: { | |||
vm = nixos-generators.nixosGenerate { | |||
system = system; | |||
specialArgs = { | |||
extraArg = "foobar"; | |||
}; | |||
modules = [ | |||
./configuration.nix | |||
]; | |||
format = "raw"; | |||
}; | |||
}); | |||
}; | |||
} | |||
</syntaxhighlight> | |||
==== modulesPath ==== | ==== modulesPath ==== | ||
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</syntaxhighlight> | </syntaxhighlight> | ||
If you're developing on top of master, this will potentially cause the compilation of lots of packages, since changes on master might not cached on cache.nixos.org yet. To avoid that, you can develop your module on top of the <code>nixos-unstable</code> [[ | If you're developing on top of master, this will potentially cause the compilation of lots of packages, since changes on master might not cached on cache.nixos.org yet. To avoid that, you can develop your module on top of the <code>nixos-unstable</code> [[Channel branches|channel branch]], tracked by the eponymous branch in https://github.com/NixOS/nixpkgs: | ||
<syntaxhighlight lang="bash"> | <syntaxhighlight lang="bash"> | ||
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</syntaxhighlight> | </syntaxhighlight> | ||
Of course, it doesn't have to be {{|c|nixos-rebuild}} in particular. | Of course, it doesn't have to be {{|c|nixos-rebuild}} in particular. | ||
== References == | == References == | ||