From a96318127dc17ee102bcf90821d90b7e6079a85d Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Wed, 25 Sep 2019 18:17:39 +0100
Subject: [PATCH] Update comments and docstring
---
synapse/metrics/background_process_metrics.py | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index b24e2fab4a..c53d2a0d40 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -175,7 +175,7 @@ def run_as_background_process(desc, func, *args, **kwargs):
Args:
desc (str): a description for this background process type
- func: a function, which may return a Deferred
+ func: a function, which may return a Deferred or a coroutine
args: positional args for func
kwargs: keyword args for func
@@ -199,11 +199,13 @@ def run_as_background_process(desc, func, *args, **kwargs):
_background_processes.setdefault(desc, set()).add(proc)
try:
- # We ensureDeferred here to handle coroutines
result = func(*args, **kwargs)
- # We need this check because ensureDeferred doesn't like when
- # func doesn't return a Deferred or coroutine.
+ # We probably don't have an ensureDeferred in our call stack to handle
+ # coroutine results, so we need to ensureDeferred here.
+ #
+ # But we need this check because ensureDeferred doesn't like being
+ # called on immediate values (as opposed to Deferreds or coroutines).
if iscoroutine(result):
result = defer.ensureDeferred(result)
--
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