nixpkgs/nixos/modules/services/misc/nix-gc.nix
pennae 2e751c0772 treewide: automatically md-convert option descriptions
the conversion procedure is simple:

 - find all things that look like options, ie calls to either `mkOption`
   or `lib.mkOption` that take an attrset. remember the attrset as the
   option
 - for all options, find a `description` attribute who's value is not a
   call to `mdDoc` or `lib.mdDoc`
 - textually convert the entire value of the attribute to MD with a few
   simple regexes (the set from mdize-module.sh)
 - if the change produced a change in the manual output, discard
 - if the change kept the manual unchanged, add some text to the
   description to make sure we've actually found an option. if the
   manual changes this time, keep the converted description

this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.
2022-07-30 15:16:34 +02:00

107 lines
2.8 KiB
Nix

{ config, lib, ... }:
with lib;
let
cfg = config.nix.gc;
in
{
###### interface
options = {
nix.gc = {
automatic = mkOption {
default = false;
type = types.bool;
description = lib.mdDoc "Automatically run the garbage collector at a specific time.";
};
dates = mkOption {
type = types.str;
default = "03:15";
example = "weekly";
description = ''
How often or when garbage collection is performed. For most desktop and server systems
a sufficient garbage collection is once a week.
The format is described in
<citerefentry><refentrytitle>systemd.time</refentrytitle>
<manvolnum>7</manvolnum></citerefentry>.
'';
};
randomizedDelaySec = mkOption {
default = "0";
type = types.str;
example = "45min";
description = ''
Add a randomized delay before each garbage collection.
The delay will be chosen between zero and this value.
This value must be a time span in the format specified by
<citerefentry><refentrytitle>systemd.time</refentrytitle>
<manvolnum>7</manvolnum></citerefentry>
'';
};
persistent = mkOption {
default = true;
type = types.bool;
example = false;
description = lib.mdDoc ''
Takes a boolean argument. If true, the time when the service
unit was last triggered is stored on disk. When the timer is
activated, the service unit is triggered immediately if it
would have been triggered at least once during the time when
the timer was inactive. Such triggering is nonetheless
subject to the delay imposed by RandomizedDelaySec=. This is
useful to catch up on missed runs of the service when the
system was powered down.
'';
};
options = mkOption {
default = "";
example = "--max-freed $((64 * 1024**3))";
type = types.str;
description = lib.mdDoc ''
Options given to {file}`nix-collect-garbage` when the
garbage collector is run automatically.
'';
};
};
};
###### implementation
config = {
assertions = [
{
assertion = cfg.automatic -> config.nix.enable;
message = ''nix.gc.automatic requires nix.enable'';
}
];
systemd.services.nix-gc = lib.mkIf config.nix.enable {
description = "Nix Garbage Collector";
script = "exec ${config.nix.package.out}/bin/nix-collect-garbage ${cfg.options}";
startAt = optional cfg.automatic cfg.dates;
};
systemd.timers.nix-gc = lib.mkIf cfg.automatic {
timerConfig = {
RandomizedDelaySec = cfg.randomizedDelaySec;
Persistent = cfg.persistent;
};
};
};
}