home-manager/modules/systemd.nix
Cornelius Mika 73b8aa8bcc
systemd: merge unit definitions recursively
This removes the need for monolithic unit definitions and allows
users to modify existing units.

Example:
```
{
  systemd.user.services.owncloud-client.Unit.OnFailure = "my-notify-service";
}
```
2018-05-10 20:13:58 +02:00

194 lines
5.2 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.systemd.user;
dag = config.lib.dag;
enabled = cfg.services != {}
|| cfg.sockets != {}
|| cfg.targets != {}
|| cfg.timers != {};
toSystemdIni = generators.toINI {
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}";
# Needed because systemd derives unit names from the ultimate
# link target.
source = pkgs.writeTextDir filename (toSystemdIni serviceCfg)
+ "/" + filename;
wantedBy = target:
{
name = "systemd/user/${target}.wants/${filename}";
value = { inherit source; };
};
in
singleton {
name = "systemd/user/${filename}";
value = { inherit source; };
}
++
map wantedBy (serviceCfg.Install.WantedBy or []);
buildServices = style: serviceCfgs:
concatLists (mapAttrsToList (buildService style) serviceCfgs);
servicesStartTimeoutMs = builtins.toString cfg.servicesStartTimeoutMs;
attrsRecursivelyMerged = types.attrs // {
merge = loc: foldl' (res: def: recursiveUpdate res def.value) {};
};
in
{
meta.maintainers = [ maintainers.rycee ];
options = {
systemd.user = {
systemctlPath = mkOption {
default = "${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 = attrsRecursivelyMerged;
description = ''
Definition of systemd per-user service units. Attributes are
merged recursively.
'';
};
sockets = mkOption {
default = {};
type = attrsRecursivelyMerged;
description = ''
Definition of systemd per-user sockets. Attributes are
merged recursively.
'';
};
targets = mkOption {
default = {};
type = attrsRecursivelyMerged;
description = ''
Definition of systemd per-user targets. Attributes are
merged recursively.
'';
};
timers = mkOption {
default = {};
type = attrsRecursivelyMerged;
description = ''
Definition of systemd per-user timers. Attributes are merged
recursively.
'';
};
startServices = mkOption {
default = false;
type = types.bool;
description = ''
Start all services that are wanted by active targets.
Additionally, stop obsolete services from the previous
generation.
'';
};
servicesStartTimeoutMs = mkOption {
default = 0;
type = types.int;
description = ''
How long to wait for started services to fail until their
start is considered successful.
'';
};
};
};
config = mkMerge [
{
assertions = [
{
assertion = enabled -> pkgs.stdenv.isLinux;
message =
let
names = concatStringsSep ", " (
attrNames (
cfg.services // cfg.sockets // cfg.targets // cfg.timers
)
);
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 =
listToAttrs (
(buildServices "service" cfg.services)
++
(buildServices "socket" cfg.sockets)
++
(buildServices "target" cfg.targets)
++
(buildServices "timer" cfg.timers)
);
# 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 = dag.entryAfter ["linkGeneration"] (
let
autoReloadCmd = ''
${pkgs.ruby}/bin/ruby ${./systemd-activate.rb} \
"''${oldGenPath=}" "$newGenPath" "${servicesStartTimeoutMs}"
'';
legacyReloadCmd = ''
bash ${./systemd-activate.sh} "''${oldGenPath=}" "$newGenPath"
'';
ensureRuntimeDir = "XDG_RUNTIME_DIR=\${XDG_RUNTIME_DIR:-/run/user/$(id -u)}";
in
''
if ${ensureRuntimeDir} ${cfg.systemctlPath} --quiet --user is-system-running 2> /dev/null; then
${ensureRuntimeDir} \
PATH=${dirOf cfg.systemctlPath}:$PATH \
${if cfg.startServices then autoReloadCmd else legacyReloadCmd}
else
echo "User systemd daemon not running. Skipping reload."
fi
''
);
})
];
}