Allow modules to schedule delayed background calls. (#15993)

* Add a module API function to provide `call_later`

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

* Add comments

* Update version number

---------

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
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reivilibre 2023-08-08 10:53:49 +00:00 committed by GitHub
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Allow modules to schedule delayed background calls.

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@ -34,6 +34,7 @@ import jinja2
from typing_extensions import ParamSpec
from twisted.internet import defer
from twisted.internet.interfaces import IDelayedCall
from twisted.web.resource import Resource
from synapse.api import errors
@ -1242,6 +1243,46 @@ class ModuleApi:
"""
return self._hs.config.worker.run_background_tasks
def delayed_background_call(
self,
msec: float,
f: Callable,
*args: object,
desc: Optional[str] = None,
**kwargs: object,
) -> IDelayedCall:
"""Wraps a function as a background process and calls it in a given number of milliseconds.
The scheduled call is not persistent: if the current Synapse instance is
restarted before the call is made, the call will not be made.
Added in Synapse v1.90.0.
Args:
msec: How long to wait before calling, in milliseconds.
f: The function to call once. f can be either synchronous or
asynchronous, and must follow Synapse's logcontext rules.
More info about logcontexts is available at
https://matrix-org.github.io/synapse/latest/log_contexts.html
*args: Positional arguments to pass to function.
desc: The background task's description. Default to the function's name.
**kwargs: Keyword arguments to pass to function.
Returns:
IDelayedCall handle from twisted, which allows to cancel the delayed call if desired.
"""
if desc is None:
desc = f.__name__
return self._clock.call_later(
# convert ms to seconds as needed by call_later.
msec * 0.001,
run_as_background_process,
desc,
lambda: maybe_awaitable(f(*args, **kwargs)),
)
async def sleep(self, seconds: float) -> None:
"""Sleeps for the given number of seconds.