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nixpkgs/nixos/modules/services/scheduling/cron.nix
Eelco Dolstra 29027fd1e1 Rewrite ‘with pkgs.lib’ -> ‘with lib’
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
2014-04-14 16:26:48 +02:00

118 lines
3.1 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
inherit (config.services) jobsTags;
# 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
${pkgs.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 = "/var/setuid-wrappers/sendmail";
};
in
{
###### interface
options = {
services.cron = {
enable = mkOption {
type = types.bool;
default = true;
description = "Whether to enable the Vixie cron daemon.";
};
mailto = mkOption {
type = types.nullOr types.str;
default = null;
description = "Email address to which job output will be mailed.";
};
systemCronJobs = mkOption {
type = types.listOf types.str;
default = [];
example = literalExample ''
[ "* * * * * test ls -l / > /tmp/cronout 2>&1"
"* * * * * eelco echo Hello World > /home/eelco/cronout"
]
'';
description = ''
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.setuidOwners</option>
If neither /var/cron/cron.deny nor /var/cron/cron.allow exist only root
will 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.
'';
};
};
};
###### implementation
config = mkIf config.services.cron.enable {
environment.etc = singleton
# The system-wide crontab.
{ source = systemCronJobsFile;
target = "crontab";
mode = "0600"; # Cron requires this.
};
security.setuidPrograms = [ "crontab" ];
environment.systemPackages = [ cronNixosPkg ];
jobs.cron =
{ description = "Cron Daemon";
startOn = "startup";
path = [ cronNixosPkg ];
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
'';
exec = "cron -n";
};
};
}