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
This is an implementation of MSC4190, which allows appservices to manage
their user's devices without /login & /logout.
---------
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
Signed-off-by: Nicolas Werner <n.werner@famedly.com>
Co-authored-by: Nicolas Werner <n.werner@famedly.com>
Co-authored-by: Nicolas Werner <89468146+nico-famedly@users.noreply.github.com>
Co-authored-by: Hubert Chathi <hubert@uhoreg.ca>
