jaytaylor.com/cron2sysdtimer

Automatically transform crontab jobs into systemd timers

Requirements

• Golang v1.17 or newer
• Linux with SystemD (naturally :)

Installation

go install jaytaylor/cron2sysdtimer@latest

Usage

cron2sysdtimer reads crontab file at /etc/crontab by default. You can specify crontab file with -f FILE flag.

systemd unit file are saved at /run/systemd/system by default. You can specify save directory with -o OUTDIR flag.

$ cron2sysdtimer
$ cron2sysdtimer -f sample.cron -o unitfiles

Example

ubuntu@ubuntu-jovial:~/src/jaytaylor.com/cron2sysdtimer$ sudo cron2sysdtimer -f sample.cron --reload
ubuntu@ubuntu-jovial:~/src/jaytaylor.com/cron2sysdtimer$ systemctl list-timers
NEXT                         LEFT                   LAST PASSED UNIT                         ACTIVATES
Fri 2017-01-20 07:50:00 UTC  4min 16s left          n/a  n/a    cron-77e2fb273c45.timer      cron-77e2fb273c45.service
Fri 2017-01-20 07:56:01 UTC  10min left             n/a  n/a    systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service
Fri 2017-01-20 08:00:00 UTC  14min left             n/a  n/a    cron-1b33d99b7dda.timer      cron-1b33d99b7dda.service
Fri 2017-01-20 10:00:00 UTC  2h 14min left          n/a  n/a    cron-b60fe106ef63.timer      cron-b60fe106ef63.service
Fri 2017-01-20 12:16:09 UTC  4h 30min left          n/a  n/a    snapd.refresh.timer          snapd.refresh.service
Fri 2017-01-20 19:11:59 UTC  11h left               n/a  n/a    apt-daily.timer              apt-daily.service
Wed 2017-02-01 00:00:00 UTC  1 weeks 4 days left    n/a  n/a    cron-fcd6d8377d9d.timer      cron-fcd6d8377d9d.service
Sat 2017-12-02 01:23:00 UTC  10 months 11 days left n/a  n/a    cron-d3c507cb2439.timer      cron-d3c507cb2439.service

8 timers listed.
Pass --all to see loaded but inactive timers, too.

Reload systemd and start all timers automatically

If --reload is provided, cron2sysdtimer reloads systemd unit files (= systemctl daemon-reload) and starts all generated timers (= systemctl start foo.timer). Maybe sudo is required to execute.

$ sudo cron2sysdtimer -f sample.cron --reload

Determine unit name from command to execute

Crontab does not have the concept of "task name", and a task name is required to identify each systemd unit.

cron2sysdtimer supports automatically generating the task name from the original command using a regular expression- Use the --name-regexp REGEXP flag.

The regex must have one capturing group.

If a regular expression is not provided or command does not match to the given regular expression, a hash value is automatically calculated and used as the unit name.

$ cron2sysdtimer -f sample.cron --name-regexp '--name ([a-zA-Z0-9_-]+)'

Delete unregistered unit files

If --delete is provided, cron2sysdtimer deletes unit files which are no longer written in the given crontab file.

$ cron2sysdtimer -f tmp/scheduler -o /run/systemd/system --delete
Deleted: /run/systemd/system/cron-19fb9c164fe8.service
Deleted: /run/systemd/system/cron-19fb9c164fe8.timer
Deleted: /run/systemd/system/cron-4f76a3902132.service
Deleted: /run/systemd/system/cron-4f76a3902132.timer

Specify unit dependencies

You can specify unit dependencies (After=) with --after AFTER flag.

$ cron2sysdtimer -f sample.crom --after docker.service

Development

Get project build dependencies

go get -u github.com/jteeuwen/go-bindata/...

Run tests

Standard:

cd $GOPATH/src/jaytaylor.com/cron2sysdtimer
go test -v ./...; echo $?

Generate static bindata assets

cd $GOPATH/src/jaytaylor.com/cron2sysdtimer
go generate ./...

License

Credits

Original Author

Forked from @dtan4's ct2stimer.git.