3.8 KiB
systemd-crontab-generator
What's it?
This is a compatibility layer for crontab-to-systemd timers framework. It works by parsing
crontab and anacrontab files from usual places like /etc/crontab
and /var/spool/cron
and generating systemd timers and services. You can use cron.target
as a single control
point for the generated units.
It's intented to be drop-in replacement for all cron implementations.
Rationale
The crontab generator for systemd (implemented in C) was already published on maillist, but was later declined by Lennart:
I am not convinced this is a really good idea. From my perspective at least it appears that we should much rather just convert the crontabs and that's it. Unlike sysv init scripts the number of crontab in use (at least on Fedora) is relatively small, and very rare in third-party packages.
Lennart
While I'm generally agree with him, I'm not totally convinced it's always convinient to herd a bunch of
separate *.timer
and *.service
files. I find convinient to have all jobs schedule in one single file,
and it's more obvious to see relations in jobs scheduling if you have several jobs on sight at once.
All things considered, I think people should have an alternative here, so I decided to support
the idea of systemd crontab generator. Though the original C implementation of crontab parser
from maillist is very incomplete: it doesn't support monotonic schedules (like @daily
or @yearly
),
it can't parse comments and environment variable settings, etc.
I'm not very good in C, so C implementation (while it's recommended for generators) whould take me ages to write, so I used Python for proof-of-concept implementation. And here comes systemd-crontab-generator.
Installation
If you are on Archlinux, install from AUR, otherwise see PKGBUILD
file and
execute commands from package()
sub.
Usage
The generator runs on system boot and when the crontabs change.
The project includes simple crontab
command equivalent, which behaves like standard crontab command
(and accepts the same main options).
To control cron jobs, use cron.target
, e.g. to start and enable cron after installation:
# systemctl enable cron.target
# systemctl start cron.target
Disclaimer
This is a beta product! Use at your own risk! I'm not responsible for any data losses, time losses, money losses or any other failures due to usage or misusage of this project! I've run this product on my local server for several months without issues, but it does not mean you will have no issues as well! Don't blame me for any crashes because of the product! You were warned!
License
The project is licensed under CC-BY. Don't forget to attribute if you derive from my work! Also, specially for systemd-cron, the project is licensed under MIT license for compatibility.
Contribution
You are most welcome to post bugs and PRs! Also check out comments in AUR for current news about Arch package status.
Copyright
© 2014, Konstantin Stepanov (me@kstep.me)