This reports the total count of users (split by appservice) which is
meant to be the monthless counterpart to the MAU metric.
Context:
> So this is largely for billing purposes and wanting to know the change
in the number of users. If a user is deactivated then we no longer want
to count them. Consumers *might* want to count appservice users, and
maybe count them based on the service (perhaps you change more for users
under bridge X or bridge Y).
>
> *-- https://github.com/element-hq/synapse/pull/19848#discussion_r3402216234*
We have various constants to try and avoid mistyping of durations, e.g.
`ONE_HOUR_SECONDS * MILLISECONDS_PER_SECOND`, however this can get a
little verbose and doesn't help with typing.
Instead, let's move towards a dedicated `Duration` class (basically a
[`timedelta`](https://docs.python.org/3/library/datetime.html#timedelta-objects)
with helper methods).
This PR introduces the new types and converts all usages of the existing
constants with it. Future PRs may work to move the clock methods to also
use it (e.g. `call_later` and `looping_call`).
Reviewable commit-by-commit.
Introduce `Clock.call_when_running(...)` to wrap startup code in a
logcontext, ensuring we can identify which server generated the logs.
Background:
> Ideally, nothing from the Synapse homeserver would be logged against the `sentinel`
> logcontext as we want to know which server the logs came from. In practice, this is not
> always the case yet especially outside of request handling.
>
> Global things outside of Synapse (e.g. Twisted reactor code) should run in the
> `sentinel` logcontext. It's only when it calls into application code that a logcontext
> gets activated. This means the reactor should be started in the `sentinel` logcontext,
> and any time an awaitable yields control back to the reactor, it should reset the
> logcontext to be the `sentinel` logcontext. This is important to avoid leaking the
> current logcontext to the reactor (which would then get picked up and associated with
> the next thing the reactor does).
>
> *-- `docs/log_contexts.md`
Also adds a lint to prefer `Clock.call_when_running(...)` over
`reactor.callWhenRunning(...)`
Part of https://github.com/element-hq/synapse/issues/18905
Reverts element-hq/synapse#18260
It is causing a failure when building release debs for `debian:bullseye`
with the following error:
```
sqlite3.OperationalError: near "RETURNING": syntax error
```
Will Hunt