mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-03 20:33:21 +00:00
d88721e440
This is based on a prototype Nicolas B. Pierron worked on during a discussion we had at FOSDEM. A new version with a workaround for problems of the reverted original. Discussion: https://github.com/NixOS/nixpkgs/commit/3f2566689
76 lines
2.3 KiB
XML
76 lines
2.3 KiB
XML
<section xmlns="http://docbook.org/ns/docbook"
|
|
xmlns:xlink="http://www.w3.org/1999/xlink"
|
|
xmlns:xi="http://www.w3.org/2001/XInclude"
|
|
version="5.0"
|
|
xml:id="sec-replace-modules">
|
|
|
|
<title>Replace Modules</title>
|
|
|
|
<para>Modules that are imported can also be disabled. The option
|
|
declarations and config implementation of a disabled module will be
|
|
ignored, allowing another to take it's place. This can be used to
|
|
import a set of modules from another channel while keeping the rest
|
|
of the system on a stable release.</para>
|
|
<para><literal>disabledModules</literal> is a top level attribute like
|
|
<literal>imports</literal>, <literal>options</literal> and
|
|
<literal>config</literal>. It contains a list of modules that will
|
|
be disabled. This can either be the full path to the module or a
|
|
string with the filename relative to the modules path
|
|
(eg. <nixpkgs/nixos/modules> for nixos).
|
|
</para>
|
|
|
|
<para>This example will replace the existing postgresql module with
|
|
the version defined in the nixos-unstable channel while keeping the
|
|
rest of the modules and packages from the original nixos channel.
|
|
This only overrides the module definition, this won't use postgresql
|
|
from nixos-unstable unless explicitly configured to do so.</para>
|
|
|
|
<programlisting>
|
|
{ config, lib, pkgs, ... }:
|
|
|
|
{
|
|
disabledModules = [ "services/databases/postgresql.nix" ];
|
|
|
|
imports =
|
|
[ # Use postgresql service from nixos-unstable channel.
|
|
# sudo nix-channel --add http://nixos.org/channels/nixos-unstable nixos-unstable
|
|
<nixos-unstable/nixos/modules/services/databases/postgresql.nix>
|
|
];
|
|
|
|
services.postgresql.enable = true;
|
|
}
|
|
</programlisting>
|
|
|
|
<para>This example shows how to define a custom module as a
|
|
replacement for an existing module. Importing this module will
|
|
disable the original module without having to know it's
|
|
implementation details.</para>
|
|
|
|
<programlisting>
|
|
{ config, lib, pkgs, ... }:
|
|
|
|
with lib;
|
|
|
|
let
|
|
cfg = config.programs.man;
|
|
in
|
|
|
|
{
|
|
disabledModules = [ "services/programs/man.nix" ];
|
|
|
|
options = {
|
|
programs.man.enable = mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description = "Whether to enable manual pages.";
|
|
};
|
|
};
|
|
|
|
config = mkIf cfg.enabled {
|
|
warnings = [ "disabled manpages for production deployments." ];
|
|
};
|
|
}
|
|
</programlisting>
|
|
|
|
</section>
|