Cron containers were never reaped once they exceeded their active deadline, so a hung cron task ran indefinitely instead of being retired after 24 hours as documented. `cron:run` now also accepts a `--ttl-seconds` argument, matching the one `dokku run` already takes.
The docker-local scheduler wrote each app.json cron command verbatim into the dokku user's crontab, where cron's `bash -c` interpreted any shell metacharacters in the command on the host as the dokku user rather than inside the container. The crontab line is now `dokku cron:run <app> <cron-id>`, and the command is resolved from app.json and exec'd inside the container at run time. Commands containing shell operators are also rejected when app.json is validated at deploy time.
The io/ioutil package has been deprecated as of Go 1.16 [1]. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
[1]: https://golang.org/doc/go1.16#ioutil
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
The implementation was very heavily docker-local specific and thus didn't make a ton of sense to keep in the cron plugin.
This also re-introduces changes from #5908 to parallelize the crontab generation (which is also specific to the docker-local scheduler) that were lost during a rebase.
The impetus for this change was implementing a `cron:run` command. The logic for actually running the command isn't scheduler specific - merely invoking `dokku run` with the appropriate arguments - but all the logic around how the commands were retrieved were, so the change was made pre-emptively.
