diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py
index ff67b1d794..990216145e 100644
--- a/synapse/util/logcontext.py
+++ b/synapse/util/logcontext.py
@@ -310,6 +310,10 @@ def preserve_context_over_fn(fn, *args, **kwargs):
def preserve_context_over_deferred(deferred, context=None):
"""Given a deferred wrap it such that any callbacks added later to it will
be invoked with the current context.
+
+ Deprecated: this almost certainly doesn't do want you want, ie make
+ the deferred follow the synapse logcontext rules: try
+ ``make_deferred_yieldable`` instead.
"""
if context is None:
context = LoggingContext.current_context()
@@ -330,12 +334,8 @@ def preserve_fn(f):
LoggingContext.set_current_context(LoggingContext.sentinel)
return result
- # XXX: why is this here rather than inside g? surely we want to preserve
- # the context from the time the function was called, not when it was
- # wrapped?
- current = LoggingContext.current_context()
-
def g(*args, **kwargs):
+ current = LoggingContext.current_context()
res = f(*args, **kwargs)
if isinstance(res, defer.Deferred) and not res.called:
# The function will have reset the context before returning, so
@@ -359,6 +359,25 @@ def preserve_fn(f):
return g
+@defer.inlineCallbacks
+def make_deferred_yieldable(deferred):
+ """Given a deferred, 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
+ result/failure).
+
+ If the deferred has not yet completed, resets the logcontext before
+ returning a deferred. Then, when the deferred completes, restores the
+ current logcontext before running callbacks/errbacks.
+
+ (This is more-or-less the opposite operation to preserve_fn.)
+ """
+ with PreserveLoggingContext():
+ r = yield deferred
+ defer.returnValue(r)
+
+
# modules to ignore in `logcontext_tracer`
_to_ignore = [
"synapse.util.logcontext",
|
