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nixpkgs/nixos/lib/eval-config.nix
Arian van Putten 2e75a7b516 nixos: doc: optionally include all modules in manual generation
Before this change `man 5 configuration.nix` would only show options of modules in
the `baseModules` set, which consists only of the list of modules in
`nixos/modules/module-list.nix`

With this change applied and `documentation.nixos.includeAllModules` option enabled
all modules included in `configuration.nix` file will be used instead.

This makes configurations with custom modules self-documenting. It also means
that importing non-`baseModules` modules like `gce.nix` or `azure.nix`
will make their documentation available in `man 5 configuration.nix`.

`documentation.nixos.includeAllModules` is currently set to `false` by
default as enabling it usually uncovers bugs and prevents evaluation.
It should be set to `true` in a release or two.

This was originally implemented in #47177, edited for more configurability,
documented and rebased onto master by @oxij.
2019-03-05 09:41:40 +00:00

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Nix

# From an end-user configuration file (`configuration.nix'), build a NixOS
# configuration object (`config') from which we can retrieve option
# values.
# !!! Please think twice before adding to this argument list!
# Ideally eval-config.nix would be an extremely thin wrapper
# around lib.evalModules, so that modular systems that have nixos configs
# as subcomponents (e.g. the container feature, or nixops if network
# expressions are ever made modular at the top level) can just use
# types.submodule instead of using eval-config.nix
{ # !!! system can be set modularly, would be nice to remove
system ? builtins.currentSystem
, # !!! is this argument needed any more? The pkgs argument can
# be set modularly anyway.
pkgs ? null
, # !!! what do we gain by making this configurable?
baseModules ? import ../modules/module-list.nix
, # !!! See comment about args in lib/modules.nix
extraArgs ? {}
, # !!! See comment about args in lib/modules.nix
specialArgs ? {}
, modules
, # !!! See comment about check in lib/modules.nix
check ? true
, prefix ? []
, lib ? import ../../lib
}:
let extraArgs_ = extraArgs; pkgs_ = pkgs;
extraModules = let e = builtins.getEnv "NIXOS_EXTRA_MODULE_PATH";
in if e == "" then [] else [(import e)];
in
let
pkgsModule = rec {
_file = ./eval-config.nix;
key = _file;
config = {
# Explicit `nixpkgs.system` or `nixpkgs.localSystem` should override
# this. Since the latter defaults to the former, the former should
# default to the argument. That way this new default could propagate all
# they way through, but has the last priority behind everything else.
nixpkgs.system = lib.mkDefault system;
_module.args.pkgs = lib.mkIf (pkgs_ != null) (lib.mkForce pkgs_);
};
};
in rec {
# Merge the option definitions in all modules, forming the full
# system configuration.
inherit (lib.evalModules {
inherit prefix check;
modules = baseModules ++ extraModules ++ [ pkgsModule ] ++ modules;
args = extraArgs;
specialArgs =
{ modulesPath = builtins.toString ../modules; } // specialArgs;
}) config options;
# These are the extra arguments passed to every module. In
# particular, Nixpkgs is passed through the "pkgs" argument.
extraArgs = extraArgs_ // {
inherit baseModules extraModules modules;
};
inherit (config._module.args) pkgs;
}