Files
ignacionelson 6340b71dca Report recent usage and whether the scheduler is alive
projectsend:status could say what an installation holds and how many
accounts it has, but nothing about whether anybody was using it. Adds a
`usage` block -- downloads split staff/clients/anonymous, uploads, and
five allowlisted action counts -- plus `activity.last_client_login_at`,
`health.scheduler` and `health.failed_jobs_latest_at`.

The scheduler is the one worth having on its own. `health.queues`
catches a dead worker; nothing caught a dead scheduler, and its first
symptom is not a stalled feature but an expired file that is still
downloadable, because the job that was going to remove it stopped
running weeks ago. Nothing about the installation looks wrong while that
is true.

`failed_jobs_latest_at` exists because the count beside it cannot say
whether anything is wrong *now*, and reading it as though it could is a
category error rather than a threshold wanting tuning. The table is
swept daily, so the count spans a retention window -- one the
installation chooses, and one that can be set to keep-forever by
somebody who treats a failed job as evidence rather than debris. Two
identical installations therefore report different numbers, and on a
keep-forever one the count grows until any fixed threshold trips. A
timestamp is independent of how long rows are kept: 27 failures whose
newest is three weeks old is an installation that has been healthy for
three weeks and has not been swept yet.

`usage` is a rolling window with no lifetime totals, and that is a
correctness decision rather than a presentational one: activity_log is
never pruned, so a lifetime count over it gets slower every day of the
installation's life while a windowed one stays flat. The window is
emitted as `window_days` rather than left for the reader to assume.

The actions are an allowlist, not a `group by action`. This document
leaves the installation and Action gains cases most weeks, so an open
group-by would ship new action names outward with nobody having decided
they should go -- and some of them (account.erased, two_factor.reset)
are somebody's compliance event, not a business metric. It is also ~30x
cheaper: five keyed counts ride (action, created_at) while a group-by
starts from created_at and reads rows. The scheduler's failure message
and the queue exception text are omitted for the same reason; they are
the fields here that can carry a path or a stack trace, and a count with
a timestamp says "go and look", which is all a watcher is owed.

The two indexes ship as a pair and the migration explains at length why.
Measured at 2.1M rows: adding (action, created_at) alone fixes the
windowed counts and takes last_staff_login_at -- already running hourly
on every tenant -- from 0.63s to 7.7s, because the planner switches to
it, still needs actor_type, and does a scattered primary-key lookup per
row. With both, that query is answered from the index without reading a
row at all (0.0004s) and the whole new usage block costs ~70ms.

Also documents the keys as a contract, the way `capabilities` already
is. This one fails worse: a renamed capability key breaks a comparison
somebody is watching, a renamed usage key produces a chart that is
silently empty, and nobody gets paged for a flat line.
2026-08-31 18:51:47 -03:00
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