nixpkgs/nixos/modules/services/scheduling/cron.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

138 lines
3.9 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
# Put all the system cronjobs together.
systemCronJobsFile = pkgs.writeText "system-crontab"
''
SHELL=${pkgs.bash}/bin/bash
PATH=${config.system.path}/bin:${config.system.path}/sbin
${optionalString (config.services.cron.mailto != null) ''
MAILTO="${config.services.cron.mailto}"
''}
NIX_CONF_DIR=/etc/nix
${lib.concatStrings (map (job: job + "\n") config.services.cron.systemCronJobs)}
'';
# Vixie cron requires build-time configuration for the sendmail path.
cronNixosPkg = pkgs.cron.override {
# The mail.nix nixos module, if there is any local mail system enabled,
# should have sendmail in this path.
sendmailPath = "/run/wrappers/bin/sendmail";
};
allFiles =
optional (config.services.cron.systemCronJobs != []) systemCronJobsFile
++ config.services.cron.cronFiles;
in
{
###### interface
options = {
services.cron = {
enable = mkOption {
type = types.bool;
default = false;
description = lib.mdDoc "Whether to enable the Vixie cron daemon.";
};
mailto = mkOption {
type = types.nullOr types.str;
default = null;
description = lib.mdDoc "Email address to which job output will be mailed.";
};
systemCronJobs = mkOption {
type = types.listOf types.str;
default = [];
example = literalExpression ''
[ "* * * * * test ls -l / > /tmp/cronout 2>&1"
"* * * * * eelco echo Hello World > /home/eelco/cronout"
]
'';
description = lib.mdDoc ''
A list of Cron jobs to be appended to the system-wide
crontab. See the manual page for crontab for the expected
format. If you want to get the results mailed you must setuid
sendmail. See {option}`security.wrappers`
If neither /var/cron/cron.deny nor /var/cron/cron.allow exist only root
is allowed to have its own crontab file. The /var/cron/cron.deny file
is created automatically for you, so every user can use a crontab.
Many nixos modules set systemCronJobs, so if you decide to disable vixie cron
and enable another cron daemon, you may want it to get its system crontab
based on systemCronJobs.
'';
};
cronFiles = mkOption {
type = types.listOf types.path;
default = [];
description = lib.mdDoc ''
A list of extra crontab files that will be read and appended to the main
crontab file when the cron service starts.
'';
};
};
};
###### implementation
config = mkMerge [
{ services.cron.enable = mkDefault (allFiles != []); }
(mkIf (config.services.cron.enable) {
security.wrappers.crontab =
{ setuid = true;
owner = "root";
group = "root";
source = "${cronNixosPkg}/bin/crontab";
};
environment.systemPackages = [ cronNixosPkg ];
environment.etc.crontab =
{ source = pkgs.runCommand "crontabs" { inherit allFiles; preferLocalBuild = true; }
''
touch $out
for i in $allFiles; do
cat "$i" >> $out
done
'';
mode = "0600"; # Cron requires this.
};
systemd.services.cron =
{ description = "Cron Daemon";
wantedBy = [ "multi-user.target" ];
preStart =
''
mkdir -m 710 -p /var/cron
# By default, allow all users to create a crontab. This
# is denoted by the existence of an empty cron.deny file.
if ! test -e /var/cron/cron.allow -o -e /var/cron/cron.deny; then
touch /var/cron/cron.deny
fi
'';
restartTriggers = [ config.time.timeZone ];
serviceConfig.ExecStart = "${cronNixosPkg}/bin/cron -n";
};
})
];
}