home-manager/modules/systemd.nix
Tad Fisher 23769994e8
xdg.systemDirs: init module (#1797)
There is a need to manage XDG Base Directory system directory
environment variables in Home Manager modules. There is an existing
mechanism in `targets.genericLinux.extraXdgDataDirs', but this does not
apply to NixOS systems.

Furthermore, it is important that `XDG_CONFIG_DIRS' and `XDG_DATA_DIRS'
are set in both login shells (to support getty and SSH sessions) as well
as the systemd user manager (to propagate them to user services and
desktop environments).

The first need is addressed by adding the `xdg.systemDirs' module, which
configures lists of directory names for both `config' and `data'
directories. These are then set in
`$XDG_CONFIG_DIR/environment.d/10-home-manager.conf' and picked up by
the systemd user manager.

To make these, and other variables set in
`systemd.user.sessionVariables', available in login shells, an
additional step is added to `etc/profile.d/hm-session-vars.sh' which
exports the result of
`user-environment-generators/30-systemd-environment-d-generator' which
is shipped with systemd. The effect of this generator is to print
variables set on the systemd user manager such that shells can import
these into their environment.
2021-05-10 20:14:42 -04:00

344 lines
10 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.systemd.user;
enabled = cfg.services != {}
|| cfg.slices != {}
|| cfg.sockets != {}
|| cfg.targets != {}
|| cfg.timers != {}
|| cfg.paths != {}
|| cfg.mounts != {}
|| cfg.sessionVariables != {};
toSystemdIni = generators.toINI {
listsAsDuplicateKeys = true;
mkKeyValue = key: value:
let
value' =
if isBool value then (if value then "true" else "false")
else toString value;
in
"${key}=${value'}";
};
buildService = style: name: serviceCfg:
let
filename = "${name}.${style}";
pathSafeName = lib.replaceChars ["@" ":" "\\" "[" "]"]
["-" "-" "-" "" "" ]
filename;
# Needed because systemd derives unit names from the ultimate
# link target.
source = pkgs.writeTextFile {
name = pathSafeName;
text = toSystemdIni serviceCfg;
destination = "/${filename}";
} + "/${filename}";
wantedBy = target:
{
name = "systemd/user/${target}.wants/${filename}";
value = { inherit source; };
};
in
singleton {
name = "systemd/user/${filename}";
value = { inherit source; };
}
++
map wantedBy (serviceCfg.Install.WantedBy or []);
buildServices = style: serviceCfgs:
concatLists (mapAttrsToList (buildService style) serviceCfgs);
servicesStartTimeoutMs = builtins.toString cfg.servicesStartTimeoutMs;
unitType = unitKind: with types;
let
primitive = either bool (either int str);
in
attrsOf (attrsOf (attrsOf (either primitive (listOf primitive))))
// {
description = "systemd ${unitKind} unit configuration";
};
unitDescription = type: ''
Definition of systemd per-user ${type} units. Attributes are
merged recursively.
</para><para>
Note that the attributes follow the capitalization and naming used
by systemd. More details can be found in
<citerefentry>
<refentrytitle>systemd.${type}</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>.
'';
unitExample = type: literalExample ''
{
${toLower type}-name = {
Unit = {
Description = "Example description";
Documentation = [ "man:example(1)" "man:example(5)" ];
};
${type} = {
};
};
};
'';
sessionVariables = mkIf (cfg.sessionVariables != {}) {
"environment.d/10-home-manager.conf".text =
concatStringsSep "\n" (
mapAttrsToList (n: v: "${n}=${toString v}") cfg.sessionVariables
) + "\n";
};
in
{
meta.maintainers = [ maintainers.rycee ];
options = {
systemd.user = {
systemctlPath = mkOption {
default = "${pkgs.systemd}/bin/systemctl";
defaultText = "\${pkgs.systemd}/bin/systemctl";
type = types.str;
description = ''
Absolute path to the <command>systemctl</command> tool. This
option may need to be set if running Home Manager on a
non-NixOS distribution.
'';
};
services = mkOption {
default = {};
type = unitType "service";
description = unitDescription "service";
example = unitExample "Service";
};
slices = mkOption {
default = {};
type = unitType "slices";
description = unitDescription "slices";
example = unitExample "Slices";
};
sockets = mkOption {
default = {};
type = unitType "socket";
description = unitDescription "socket";
example = unitExample "Socket";
};
targets = mkOption {
default = {};
type = unitType "target";
description = unitDescription "target";
example = unitExample "Target";
};
timers = mkOption {
default = {};
type = unitType "timer";
description = unitDescription "timer";
example = unitExample "Timer";
};
paths = mkOption {
default = {};
type = unitType "path";
description = unitDescription "path";
example = unitExample "Path";
};
mounts = mkOption {
default = {};
type = unitType "mount";
description = unitDescription "mount";
example = unitExample "Mount";
};
startServices = mkOption {
default = "suggest";
type = with types; either bool (enum ["suggest" "legacy" "sd-switch"]);
apply = p:
if isBool p then if p then "legacy" else "suggest"
else p;
description = ''
Whether new or changed services that are wanted by active targets
should be started. Additionally, stop obsolete services from the
previous generation.
</para><para>
The alternatives are
<variablelist>
<varlistentry>
<term><literal>suggest</literal> (or <literal>false</literal>)</term>
<listitem><para>
Use a very simple shell script to print suggested
<command>systemctl</command> commands to run. You will have to
manually run those commands after the switch.
</para></listitem>
</varlistentry>
<varlistentry>
<term><literal>legacy</literal> (or <literal>true</literal>)</term>
<listitem><para>
Use a Ruby script to, in a more robust fashion, determine the
necessary changes and automatically run the
<command>systemctl</command> commands.
</para></listitem>
</varlistentry>
<varlistentry>
<term><literal>sd-switch</literal></term>
<listitem><para>
Use sd-switch, a third party application, to perform the service
updates. This tool offers more features while having a small
closure size. Note, it requires a fully functional user D-Bus
session. Once tested and deemed sufficiently robust, this will
become the default.
</para></listitem>
</varlistentry>
</variablelist>
'';
};
servicesStartTimeoutMs = mkOption {
default = 0;
type = types.ints.unsigned;
description = ''
How long to wait for started services to fail until their start is
considered successful. The value 0 indicates no timeout.
'';
};
sessionVariables = mkOption {
default = {};
type = with types; attrsOf (either int str);
example = { EDITOR = "vim"; };
description = ''
Environment variables that will be set for the user session.
The variable values must be as described in
<citerefentry>
<refentrytitle>environment.d</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>.
'';
};
};
};
config = mkMerge [
{
assertions = [
{
assertion = enabled -> pkgs.stdenv.isLinux;
message =
let
names = concatStringsSep ", " (
attrNames (
cfg.services // cfg.slices // cfg.sockets // cfg.targets
// cfg.timers // cfg.paths // cfg.mounts // cfg.sessionVariables
)
);
in
"Must use Linux for modules that require systemd: " + names;
}
];
}
# If we run under a Linux system we assume that systemd is
# available, in particular we assume that systemctl is in PATH.
(mkIf pkgs.stdenv.isLinux {
xdg.configFile = mkMerge [
(listToAttrs (
(buildServices "service" cfg.services)
++
(buildServices "slices" cfg.slices)
++
(buildServices "socket" cfg.sockets)
++
(buildServices "target" cfg.targets)
++
(buildServices "timer" cfg.timers)
++
(buildServices "path" cfg.paths)
++
(buildServices "mount" cfg.mounts)
))
sessionVariables
];
# Run systemd service reload if user is logged in. If we're
# running this from the NixOS module then XDG_RUNTIME_DIR is not
# set and systemd commands will fail. We'll therefore have to
# set it ourselves in that case.
home.activation.reloadSystemd = hm.dag.entryAfter ["linkGeneration"] (
let
cmd = {
suggest = ''
PATH=${dirOf cfg.systemctlPath}:$PATH \
bash ${./systemd-activate.sh} "''${oldGenPath=}" "$newGenPath"
'';
legacy = ''
PATH=${dirOf cfg.systemctlPath}:$PATH \
${pkgs.ruby}/bin/ruby ${./systemd-activate.rb} \
"''${oldGenPath=}" "$newGenPath" "${servicesStartTimeoutMs}"
'';
sd-switch =
let
timeoutArg =
if cfg.servicesStartTimeoutMs != 0 then
"--timeout " + servicesStartTimeoutMs
else
"";
in ''
${pkgs.sd-switch}/bin/sd-switch \
''${DRY_RUN:+--dry-run} $VERBOSE_ARG ${timeoutArg} \
''${oldGenPath:+--old-units $oldGenPath/home-files/.config/systemd/user} \
--new-units $newGenPath/home-files/.config/systemd/user
'';
};
ensureRuntimeDir = "XDG_RUNTIME_DIR=\${XDG_RUNTIME_DIR:-/run/user/$(id -u)}";
systemctl = "${ensureRuntimeDir} ${cfg.systemctlPath}";
in
''
systemdStatus=$(${systemctl} --user is-system-running 2>&1 || true)
if [[ $systemdStatus == 'running' || $systemdStatus == 'degraded' ]]; then
if [[ $systemdStatus == 'degraded' ]]; then
warnEcho "The user systemd session is degraded:"
${systemctl} --user --no-pager --state=failed
warnEcho "Attempting to reload services anyway..."
fi
${ensureRuntimeDir} \
${getAttr cfg.startServices cmd}
else
echo "User systemd daemon not running. Skipping reload."
fi
unset systemdStatus
''
);
# Export environment variables in systemd.user.sessionVariables to login shells.
home.sessionVariablesExtra = optionalString (cfg.sessionVariables != {}) ''
export $(${pkgs.systemd}/lib/systemd/user-environment-generators/30-systemd-environment-d-generator)
'';
})
];
}