nixpkgs/nixos/modules/system/etc/etc.nix
rnhmjoj 61b7cab481
treewide: use perl.withPackages when possible
Since 03eaa48 added perl.withPackages, there is a canonical way to
create a perl interpreter from a list of libraries, for use in script
shebangs or generic build inputs. This method is declarative (what we
are doing is clear), produces short shebangs[1] and needs not to wrap
existing scripts.

Unfortunately there are a few exceptions that I've found:

  1. Scripts that are calling perl with the -T switch. This makes perl
  ignore PERL5LIB, which is what perl.withPackages is using to inform
  the interpreter of the library paths.

  2. Perl packages that depends on libraries in their own path. This
  is not possible because perl.withPackages works at build time. The
  workaround is to add `-I $out/${perl.libPrefix}` to the shebang.

In all other cases I propose to switch to perl.withPackages.

[1]: https://lwn.net/Articles/779997/
2021-03-31 21:35:37 +02:00

163 lines
4.2 KiB
Nix

# Management of static files in /etc.
{ config, lib, pkgs, ... }:
with lib;
let
etc' = filter (f: f.enable) (attrValues config.environment.etc);
etc = pkgs.stdenvNoCC.mkDerivation {
name = "etc";
builder = ./make-etc.sh;
preferLocalBuild = true;
allowSubstitutes = false;
/* !!! Use toXML. */
sources = map (x: x.source) etc';
targets = map (x: x.target) etc';
modes = map (x: x.mode) etc';
users = map (x: x.user) etc';
groups = map (x: x.group) etc';
};
in
{
###### interface
options = {
environment.etc = mkOption {
default = {};
example = literalExample ''
{ example-configuration-file =
{ source = "/nix/store/.../etc/dir/file.conf.example";
mode = "0440";
};
"default/useradd".text = "GROUP=100 ...";
}
'';
description = ''
Set of files that have to be linked in <filename>/etc</filename>.
'';
type = with types; attrsOf (submodule (
{ name, config, ... }:
{ options = {
enable = mkOption {
type = types.bool;
default = true;
description = ''
Whether this /etc file should be generated. This
option allows specific /etc files to be disabled.
'';
};
target = mkOption {
type = types.str;
description = ''
Name of symlink (relative to
<filename>/etc</filename>). Defaults to the attribute
name.
'';
};
text = mkOption {
default = null;
type = types.nullOr types.lines;
description = "Text of the file.";
};
source = mkOption {
type = types.path;
description = "Path of the source file.";
};
mode = mkOption {
type = types.str;
default = "symlink";
example = "0600";
description = ''
If set to something else than <literal>symlink</literal>,
the file is copied instead of symlinked, with the given
file mode.
'';
};
uid = mkOption {
default = 0;
type = types.int;
description = ''
UID of created file. Only takes effect when the file is
copied (that is, the mode is not 'symlink').
'';
};
gid = mkOption {
default = 0;
type = types.int;
description = ''
GID of created file. Only takes effect when the file is
copied (that is, the mode is not 'symlink').
'';
};
user = mkOption {
default = "+${toString config.uid}";
type = types.str;
description = ''
User name of created file.
Only takes effect when the file is copied (that is, the mode is not 'symlink').
Changing this option takes precedence over <literal>uid</literal>.
'';
};
group = mkOption {
default = "+${toString config.gid}";
type = types.str;
description = ''
Group name of created file.
Only takes effect when the file is copied (that is, the mode is not 'symlink').
Changing this option takes precedence over <literal>gid</literal>.
'';
};
};
config = {
target = mkDefault name;
source = mkIf (config.text != null) (
let name' = "etc-" + baseNameOf name;
in mkDefault (pkgs.writeText name' config.text));
};
}));
};
};
###### implementation
config = {
system.build.etc = etc;
system.activationScripts.etc = stringAfter [ "users" "groups" ]
''
# Set up the statically computed bits of /etc.
echo "setting up /etc..."
${pkgs.perl.withPackages (p: [ p.FileSlurp ])}/bin/perl ${./setup-etc.pl} ${etc}/etc
'';
};
}