This means you can use `get_success(...)` anywhere regardless
of what kind of work needs to be done.
Spawning from adding some more async Rust things in
https://github.com/element-hq/synapse/pull/19846 and wanting something
more standard instead of the custom `till_deferred_has_result(...)` that
has crept in to a few files.
Alternative to https://github.com/element-hq/synapse/pull/19867 spurred
on by [this
comment](https://github.com/element-hq/synapse/pull/19867#discussion_r3441774685)
from @erikjohnston
### How does this work?
Previously, `get_success(...)` just ran in a hot-loop advancing the
Twisted reactor clock which didn't give any time for other threads to do
some work or acquire the GIL if necessary (whenever there is a hand-off
from Rust to Python, we need the GIL).
Now, `get_success(...)` loops until we see a result (until we hit the
~0.1s real-time timeout). In the loop, we call
[`time.sleep(0)`](https://docs.python.org/3/library/time.html#time.sleep)
which will "Suspend execution of the calling thread [...]" (CPU and GIL)
to allow other threads to do some work. Then like before, we advance the
Twisted reactor clock to run any scheduled callbacks which includes
anything the other threads may have scheduled.
### Does this slow down the entire test suite?
Seems just as fast as before. There is minutes variance in what we had
before and after but both are within the same range of each other.
(see PR for actual before/after timings)
The existing `email.smtp_host` config option is used for two distinct
purposes: it is resolved into the IP address to connect to, and used to
(request via SNI and) validate the server's certificate if TLS is
enabled. This new option allows specifying a different name for the
second purpose.
This is especially helpful, if `email.smtp_host` isn't a global FQDN,
but something that resolves only locally (e.g. "localhost" to connect
through the loopback interface, or some other internally routed name),
that one cannot get a valid certificate for.
Alternatives would of course be to specify a global FQDN as
`email.smtp_host`, or to disable TLS entirely, both of which might be
undesirable, depending on the SMTP server configuration.
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
Previously, TLS could only be used with STARTTLS.
Add a new option `force_tls`, where TLS is used from the start.
Implicit TLS is recommended over STARTLS,
see https://datatracker.ietf.org/doc/html/rfc8314Fixes#8046.
Signed-off-by: Jan Schär <jan@jschaer.ch>
Turns out that the functionality added in #10546 to skip TLS was incompatible
with older Twisted versions, so we need to be a bit more inventive.
Also, add a test to (hopefully) not break this in future. Sadly, testing TLS is
really hard.
Eric Eastwood