On 21/05/21 05.13, Lénaïc Huard wrote:
The existing mechanism for scheduling background maintenance is done through cron. On Linux systems managed by systemd, systemd provides an alternative to schedule recurring tasks: systemd timers. The main motivations to implement systemd timers in addition to cron are: * cron is optional and Linux systems running systemd might not have it installed. * The execution of `crontab -l` can tell us if cron is installed but not if the daemon is actually running. * With systemd, each service is run in its own cgroup and its logs are tagged by the service inside journald. With cron, all scheduled tasks are running in the cron daemon cgroup and all the logs of the user-scheduled tasks are pretended to belong to the system cron service. Concretely, a user that doesn’t have access to the system logs won’t have access to the log of its own tasks scheduled by cron whereas he will have access to the log of its own tasks scheduled by systemd timer.
For gender neutrality, we can use he/she instead.
Although `cron` attempts to send email, that email may go unseen by the user because these days, local mailboxes are not heavily used anymore. In order to schedule git maintenance, we need two unit template files: * ~/.config/systemd/user/git-maintenance@.service to define the command to be started by systemd and * ~/.config/systemd/user/git-maintenance@.timer to define the schedule at which the command should be run. Those units are templates that are parameterized by the frequency. Based on those templates, 3 timers are started: * git-maintenance@hourly.timer * git-maintenance@daily.timer * git-maintenance@weekly.timer The command launched by those three timers are the same as with the other scheduling methods: git for-each-repo --config=maintenance.repo maintenance run --schedule=%i with the full path for git to ensure that the version of git launched for the scheduled maintenance is the same as the one used to run `maintenance start`.
Wouldn't it be `/path/to/git for-each-repo <options>...`?
The timer unit contains `Persistent=true` so that, if the computer is powered down when a maintenance task should run, the task will be run when the computer is back powered on.
The title for this patch implied that users running Linux can choose between classic crontab or systemd timers. However, the intent of this patch is we add support for systemd timers. So let's say the title should be "maintenance: add support for systemd timers on Linux". -- An old man doll... just what I always wanted! - Clara
