nixos-container: fix nixpkgs container options being ignored

Since the introduction of option `containers.<name>.pkgs`, the
`nixpkgs.*` options (including `nixpkgs.pkgs`, `nixpkgs.config`, ...) were always
ignored in container configs, which broke existing containers.

This was due to `containers.<name>.pkgs` having two separate effects:
(1) It sets the source for the modules that are used to evaluate the container.
(2) It sets the `pkgs` arg (`_module.args.pkgs`) that is used inside the container
    modules.
    This happens even when the default value of `containers.<name>.pkgs` is unchanged, in which
    case the container `pkgs` arg is set to the pkgs of the host system.
    Previously, the `pkgs` arg was determined by the `containers.<name>.config.nixpkgs.*` options.

This commit reverts the breaking change (2) while adding a backwards-compatible way to achieve (1).
It removes option `pkgs` and adds option `nixpkgs` which implements (1).
Existing users of `pkgs` are informed by an error message to use option
`nixpkgs` or to achieve only (2) by setting option `containers.<name>.config.nixpkgs.pkgs`.
This commit is contained in:
Erik Arvstedt 2020-12-15 20:25:00 +01:00
parent 77c4fc2e89
commit 9a283a038d
No known key found for this signature in database
GPG key ID: 33312B944DD97846
2 changed files with 53 additions and 31 deletions

View file

@ -463,7 +463,6 @@ in
{ config, options, name, ... }:
{
options = {
config = mkOption {
description = ''
A specification of the desired configuration of this
@ -471,9 +470,8 @@ in
'';
type = lib.mkOptionType {
name = "Toplevel NixOS config";
merge = loc: defs: (import (config.pkgs.path + "/nixos/lib/eval-config.nix") {
merge = loc: defs: (import "${toString config.nixpkgs}/nixos/lib/eval-config.nix" {
inherit system;
pkgs = config.pkgs;
modules =
let
extraConfig = {
@ -522,12 +520,18 @@ in
'';
};
pkgs = mkOption {
type = types.attrs;
default = pkgs;
defaultText = "pkgs";
nixpkgs = mkOption {
type = types.path;
default = pkgs.path;
defaultText = "pkgs.path";
description = ''
Customise which nixpkgs to use for this container.
A path to the nixpkgs that provide the modules, pkgs and lib for evaluating the container.
To only change the <literal>pkgs</literal> argument used inside the container modules,
set the <literal>nixpkgs.*</literal> options in the container <option>config</option>.
Setting <literal>config.nixpkgs.pkgs = pkgs</literal> speeds up the container evaluation
by reusing the system pkgs, but the <literal>nixpkgs.config</literal> option in the
container config is ignored in this case.
'';
};
@ -668,14 +672,31 @@ in
'';
};
# Removed option. See `checkAssertion` below for the accompanying error message.
pkgs = mkOption { visible = false; };
} // networkOptions;
config = mkMerge
[
(mkIf options.config.isDefined {
path = config.config.system.build.toplevel;
})
];
config = let
# Throw an error when removed option `pkgs` is used.
# Because this is a submodule we cannot use `mkRemovedOptionModule` or option `assertions`.
optionPath = "containers.${name}.pkgs";
files = showFiles options.pkgs.files;
checkAssertion = if options.pkgs.isDefined then throw ''
The option definition `${optionPath}' in ${files} no longer has any effect; please remove it.
Alternatively, you can use the following options:
- containers.${name}.nixpkgs
This sets the nixpkgs (and thereby the modules, pkgs and lib) that
are used for evaluating the container.
- containers.${name}.config.nixpkgs.pkgs
This only sets the `pkgs` argument used inside the container modules.
''
else null;
in {
path = builtins.seq checkAssertion
mkIf options.config.isDefined config.config.system.build.toplevel;
};
}));
default = {};

View file

@ -1,33 +1,34 @@
import ./make-test-python.nix ({ pkgs, lib, ...} : let
customPkgs = pkgs // {
hello = pkgs.hello.overrideAttrs(old: {
name = "custom-hello";
customPkgs = pkgs.appendOverlays [ (self: super: {
hello = super.hello.overrideAttrs (old: {
name = "custom-hello";
});
};
}) ];
in {
name = "containers-custom-pkgs";
meta = with lib.maintainers; {
maintainers = [ adisbladis ];
maintainers = [ adisbladis earvstedt ];
};
machine = { ... }: {
machine = { config, ... }: {
assertions = let
helloName = (builtins.head config.containers.test.config.system.extraDependencies).name;
in [ {
assertion = helloName == "custom-hello";
message = "Unexpected value: ${helloName}";
} ];
containers.test = {
autoStart = true;
pkgs = customPkgs;
config = {pkgs, config, ... }: {
environment.systemPackages = [
pkgs.hello
];
config = { pkgs, config, ... }: {
nixpkgs.pkgs = customPkgs;
system.extraDependencies = [ pkgs.hello ];
};
};
};
testScript = ''
machine.wait_for_unit("default.target")
machine.succeed(
"test $(nixos-container run test -- readlink -f /run/current-system/sw/bin/hello) = ${customPkgs.hello}/bin/hello"
)
'';
# This test only consists of evaluating the test machine
testScript = "";
})