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{ config, lib, pkgs, ... }:
with lib;
with import ../boot/systemd-unit-options.nix { inherit config lib; };
let
userExists = u:
(u == "") || any (uu: uu.name == u) (attrValues config.users.extraUsers);
groupExists = g:
(g == "") || any (gg: gg.name == g) (attrValues config.users.extraGroups);
makeJobScript = name: content: "${pkgs.writeScriptBin name content}/bin/${name}";
# From a job description, generate an systemd unit file.
makeUnit = job:
let
hasMain = job.script != "" || job.exec != "";
env = job.environment;
preStartScript = makeJobScript "${job.name}-pre-start"
''
#! ${pkgs.stdenv.shell} -e
${job.preStart}
'';
startScript = makeJobScript "${job.name}-start"
''
#! ${pkgs.stdenv.shell} -e
${if job.script != "" then job.script else ''
exec ${job.exec}
''}
'';
postStartScript = makeJobScript "${job.name}-post-start"
''
#! ${pkgs.stdenv.shell} -e
${job.postStart}
'';
preStopScript = makeJobScript "${job.name}-pre-stop"
''
#! ${pkgs.stdenv.shell} -e
${job.preStop}
'';
postStopScript = makeJobScript "${job.name}-post-stop"
''
#! ${pkgs.stdenv.shell} -e
${job.postStop}
'';
in {
inherit (job) description requires before partOf environment path restartIfChanged unitConfig;
after =
(if job.startOn == "stopped udevtrigger" then [ "systemd-udev-settle.service" ] else
if job.startOn == "started udev" then [ "systemd-udev.service" ] else
if job.startOn == "started network-interfaces" then [ "network-interfaces.target" ] else
if job.startOn == "started networking" then [ "network.target" ] else
if job.startOn == "ip-up" then [] else
if job.startOn == "" || job.startOn == "startup" then [] else
builtins.trace "Warning: job ‘${job.name}’ has unknown startOn value ‘${job.startOn}’." []
) ++ job.after;
wants =
(if job.startOn == "stopped udevtrigger" then [ "systemd-udev-settle.service" ] else []
) ++ job.wants;
wantedBy =
(if job.startOn == "" then [] else
if job.startOn == "ip-up" then [ "ip-up.target" ] else
[ "multi-user.target" ]) ++ job.wantedBy;
serviceConfig =
job.serviceConfig
// optionalAttrs (job.preStart != "" && (job.script != "" || job.exec != ""))
{ ExecStartPre = preStartScript; }
// optionalAttrs (job.preStart != "" && job.script == "" && job.exec == "")
{ ExecStart = preStartScript; }
// optionalAttrs (job.script != "" || job.exec != "")
{ ExecStart = startScript; }
// optionalAttrs (job.postStart != "")
{ ExecStartPost = postStartScript; }
// optionalAttrs (job.preStop != "")
{ ExecStop = preStopScript; }
// optionalAttrs (job.postStop != "")
{ ExecStopPost = postStopScript; }
// (if job.script == "" && job.exec == "" then { Type = "oneshot"; RemainAfterExit = true; } else
if job.daemonType == "fork" || job.daemonType == "daemon" then { Type = "forking"; GuessMainPID = true; } else
if job.daemonType == "none" then { } else
throw "invalid daemon type `${job.daemonType}'")
// optionalAttrs (!job.task && !(job.script == "" && job.exec == "") && job.respawn)
{ Restart = "always"; }
// optionalAttrs job.task
{ Type = "oneshot"; RemainAfterExit = false; };
};
jobOptions = serviceOptions // {
name = mkOption {
# !!! The type should ensure that this could be a filename.
type = types.str;
example = "sshd";
description = ''
Name of the job, mapped to the systemd unit
<literal><replaceable>name</replaceable>.service</literal>.
'';
};
startOn = mkOption {
#type = types.str;
default = "";
description = ''
The Upstart event that triggers this job to be started. Some
are mapped to systemd dependencies; otherwise you will get a
warning. If empty, the job will not start automatically.
'';
};
stopOn = mkOption {
type = types.str;
default = "starting shutdown";
description = ''
Ignored; this was the Upstart event that triggers this job to be stopped.
'';
};
postStart = mkOption {
type = types.lines;
default = "";
description = ''
Shell commands executed after the job is started (i.e. after
the job's main process is started), but before the job is
considered “running”.
'';
};
preStop = mkOption {
type = types.lines;
default = "";
description = ''
Shell commands executed before the job is stopped
(i.e. before systemd kills the job's main process). This can
be used to cleanly shut down a daemon.
'';
};
postStop = mkOption {
type = types.lines;
default = "";
description = ''
Shell commands executed after the job has stopped
(i.e. after the job's main process has terminated).
'';
};
exec = mkOption {
type = types.str;
default = "";
description = ''
Command to start the job's main process. If empty, the
job has no main process, but can still have pre/post-start
and pre/post-stop scripts, and is considered “running”
until it is stopped.
'';
};
respawn = mkOption {
type = types.bool;
default = true;
description = ''
Whether to restart the job automatically if its process
ends unexpectedly.
'';
};
task = mkOption {
type = types.bool;
default = false;
description = ''
Whether this job is a task rather than a service. Tasks
are executed only once, while services are restarted when
they exit.
'';
};
daemonType = mkOption {
type = types.str;
default = "none";
description = ''
Determines how systemd detects when a daemon should be
considered “running”. The value <literal>none</literal> means
that the daemon is considered ready immediately. The value
<literal>fork</literal> means that the daemon will fork once.
The value <literal>daemon</literal> means that the daemon will
fork twice. The value <literal>stop</literal> means that the
daemon will raise the SIGSTOP signal to indicate readiness.
'';
};
setuid = mkOption {
type = types.addCheck types.str userExists;
default = "";
description = ''
Run the daemon as a different user.
'';
};
setgid = mkOption {
type = types.addCheck types.str groupExists;
default = "";
description = ''
Run the daemon as a different group.
'';
};
path = mkOption {
default = [];
description = ''
Packages added to the job's <envar>PATH</envar> environment variable.
Both the <filename>bin</filename> and <filename>sbin</filename>
subdirectories of each package are added.
'';
};
};
upstartJob = { name, config, ... }: {
options = {
unit = mkOption {
default = makeUnit config;
description = "Generated definition of the systemd unit corresponding to this job.";
};
};
config = {
# The default name is the name extracted from the attribute path.
name = mkDefault name;
};
};
in
{
###### interface
options = {
jobs = mkOption {
default = {};
description = ''
This option is a legacy method to define system services,
dating from the era where NixOS used Upstart instead of
systemd. You should use <option>systemd.services</option>
instead. Services defined using <option>jobs</option> are
mapped automatically to <option>systemd.services</option>, but
may not work perfectly; in particular, most
<option>startOn</option> conditions are not supported.
'';
type = types.loaOf types.optionSet;
options = [ jobOptions upstartJob ];
};
};
###### implementation
config = {
systemd.services =
flip mapAttrs' config.jobs (name: job:
nameValuePair job.name job.unit);
};
}
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