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nixpkgs/nixos/modules/misc/nixos.nix
Nicolas B. Pierron a5992ad61b Add a way to pin a NixOS version within the module system.
This modification add a way to re-evaluate the module system with a
different version of NixOS, or with a different set of arguments.
2015-11-19 20:58:45 +00:00

83 lines
2.4 KiB
Nix

{ config, options, lib, ... }:
# This modules is used to inject a different NixOS version as well as its
# argument such that one can pin a specific version with the versionning
# system of the configuration.
let
nixosReentry = import config.nixos.path {
inherit (config.nixos) configuration extraModules;
inherit (config.nixpkgs) system;
reEnter = true;
};
in
with lib;
{
options = {
nixos.path = mkOption {
default = null;
example = literalExample "./nixpkgs-15.09/nixos";
type = types.nullOr types.path;
description = ''
This option give the ability to evaluate the current set of modules
with a different version of NixOS. This option can be used version
the version of NixOS with the configuration without relying on the
<literal>NIX_PATH</literal> environment variable.
'';
};
nixos.system = mkOption {
example = "i686-linux";
type = types.uniq types.str;
description = ''
Name of the system used to compile NixOS.
'';
};
nixos.extraModules = mkOption {
default = [];
example = literalExample "mkIf config.services.openssh.enable [ ./sshd-config.nix ]";
type = types.listOf types.unspecified;
description = ''
Define additional modules which would be loaded to evaluate the
configuration.
'';
};
nixos.configuration = mkOption {
type = types.unspecified;
internal = true;
description = ''
Option used by <filename>nixos/default.nix</filename> to re-inject
the same configuration module as the one used for the current
execution.
'';
};
nixos.reflect = mkOption {
default = { inherit config options; };
type = types.unspecified;
internal = true;
description = ''
Provides <literal>config</literal> and <literal>options</literal>
computed by the module system and given as argument to all
modules. These are used for introspection of options and
configuration by tools such as <literal>nixos-option</literal>.
'';
};
};
config = mkMerge [
(mkIf (config.nixos.path != null) (mkForce {
system.build.toplevel = nixosReentry.system;
system.build.vm = nixosReentry.vm;
nixos.reflect = { inherit (nixosReentry) config options; };
}))
{ meta.maintainers = singleton lib.maintainers.pierron;
meta.doc = ./nixos.xml;
}
];
}