Convert crontab to systemd timer
ubuntu@ubuntu-xenial:~/src/github.com/dtan4/ct2stimer$ sudo ct2stimer -f sample.cron --reload
ubuntu@ubuntu-xenial:~/src/github.com/dtan4/ct2stimer$ 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.TBD
ct2stimer 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.
$ ct2stimer
$ ct2stimer -f sample.cron -o unitfilesIf --reload is provided, ct2stimer reloads systemd unit files (= systemctl daemon-reload) and starts all generated timers (= systemctl start foo.timer). Maybe sudo is required to execute.
$ sudo ct2stimer -f sample.cron --reloadAs you know, crontab does not have the concept of "task name". However, task name is required to identify each systemd unit.
You can extract task name from original command using regular expression. --name-regexp REGEXP flag is used for this.
Regular expression must have one capturing group.
If regular expression is not provided or command does not match to the given regular expression, hash value, which is calculated from command, is used for unit name.
$ ct2stimer -f sample.cron --name-regexp '--name ([a-zA-Z0-9_-]+)'If --delete is provided, ct2timer deletes unit files which are no longer written in the given crontab file.
$ ct2stimer -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.timerYou can specify unit dependencies (After=) with --after AFTER flag.
$ ct2stimer -f sample.crom --after docker.serviceBuilding and executing on Ubuntu 16.04 VM is easy so that macOS does not have systemd.
$ go get -d github.com/dtan4/ct2stimer
$ cd $GOPATH/src/github.com/dtan4/ct2stimer
$ vagrant up
$ vagrant ssh
ubuntu@ubuntu-xenial:~/src/github.com/dtan4/ct2timer$ make deps
ubuntu@ubuntu-xenial:~/src/github.com/dtan4/ct2timer$ make
ubuntu@ubuntu-xenial:~/src/github.com/dtan4/ct2timer$ bin/ct2stimerDaisuke Fujita (@dtan4)
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