36.1 Jobs

The database registers these jobs itself:

Job	What it does	Argument
`backup`	Writes a backup: a copy of the log, or of the current state when Truncate backups is on	`keep`: never deleted by `delete-old-backups`. `truncate` or `copy` overrides the setting. Combine: `keep,truncate`
`delete-old-backups`	Deletes the backups the retention settings do not keep. Backups marked keep stay	none
`truncate-log`	Rewrites the log as the current state, giving up the history and the option to revert into it. Skipped while a revert window is open	`delete-old`: deletes the old log file afterwards
`delete-old-log-files`	Deletes the log files that truncations left behind	none
`save-state`	Writes the state snapshot and the index states, so the next open does not replay the log	none
`purge-caches`	Halves the node and set caches and frees the memory	none
`reindex-text`	Queues every node of the text-indexed types for text indexing again	none
`delete-unreferenced-files`	Deletes the files no node refers to, except those uploaded in the last 15 minutes	`count`: only counts them

A built-in job given an argument it does not take fails its run and names the ones it takes, so a typo in a schedule does not go unnoticed.

Register your own jobs in OnStoreInit. It runs every time the database is set up, before it opens, so a schedule that names the job finds it from the first tick:

builder.AddRelatudeDB(options => {
    options.OnStoreInit = db => {
        db.Jobs.Add("send-digest", async ctx => {
            var sent = await Digest.SendAsync(db, ctx.Argument, ctx.CancellationToken);
            ctx.Report(sent + " mails sent"); // shown beside the run on the Scheduler page
        }, "Mails the daily digest to every subscriber", "Who gets it: all, or staff");
    };
});

The last two arguments describe the job and its argument on the Scheduler page. The job is handed a JobContext:

Member	What it is
`Argument`	The schedule's `Argument`, or the one given when the job was started by hand
`CancellationToken`	Cancelled when the database closes or someone stops the run. Pass it on: a closing database waits only a few seconds
`Report(message)`	One line on how it went, shown on the Scheduler page and written to the system log
`Progress(percentage, text)`	Shown with the database's other activities while the job runs
`ScheduleId`, `ScheduleName`, `DueUtc`, `Trigger`	Which schedule started it, for which time, and how: `Schedule`, `Missed` or `Manual`

A job that throws fails its run. The error is shown on the Scheduler page and logged, and the failed batch stays on the Tasks page for a day, where Queue again runs it again. To start a run from code, call db.Jobs.Run("send-digest", "staff"). It queues the run and returns at once.