Merge pull request #6505 from matrix-org/erikj/make_deferred_yiedable

Fix `make_deferred_yieldable` to work with coroutines
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Erik Johnston 2019-12-10 14:20:26 +00:00 committed by GitHub
commit 35f3c366ef
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3 changed files with 35 additions and 1 deletions

1
changelog.d/6505.misc Normal file
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@ -0,0 +1 @@
Make `make_deferred_yieldable` to work with async/await.

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@ -23,6 +23,7 @@ them.
See doc/log_contexts.rst for details on how this works.
"""
import inspect
import logging
import threading
import types
@ -612,7 +613,8 @@ def run_in_background(f, *args, **kwargs):
def make_deferred_yieldable(deferred):
"""Given a deferred, make it follow the Synapse logcontext rules:
"""Given a deferred (or coroutine), make it follow the Synapse logcontext
rules:
If the deferred has completed (or is not actually a Deferred), essentially
does nothing (just returns another completed deferred with the
@ -624,6 +626,13 @@ def make_deferred_yieldable(deferred):
(This is more-or-less the opposite operation to run_in_background.)
"""
if inspect.isawaitable(deferred):
# If we're given a coroutine we convert it to a deferred so that we
# run it and find out if it immediately finishes, it it does then we
# don't need to fiddle with log contexts at all and can return
# immediately.
deferred = defer.ensureDeferred(deferred)
if not isinstance(deferred, defer.Deferred):
return deferred

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@ -179,6 +179,30 @@ class LoggingContextTestCase(unittest.TestCase):
nested_context = nested_logging_context(suffix="bar")
self.assertEqual(nested_context.request, "foo-bar")
@defer.inlineCallbacks
def test_make_deferred_yieldable_with_await(self):
# an async function which retuns an incomplete coroutine, but doesn't
# follow the synapse rules.
async def blocking_function():
d = defer.Deferred()
reactor.callLater(0, d.callback, None)
await d
sentinel_context = LoggingContext.current_context()
with LoggingContext() as context_one:
context_one.request = "one"
d1 = make_deferred_yieldable(blocking_function())
# make sure that the context was reset by make_deferred_yieldable
self.assertIs(LoggingContext.current_context(), sentinel_context)
yield d1
# now it should be restored
self._check_test_key("one")
# a function which returns a deferred which has been "called", but
# which had a function which returned another incomplete deferred on