From f0ba34f581906e3809de6313bc48b696ac4ef07c Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Fri, 1 Feb 2019 12:22:57 +0000
Subject: [PATCH] Fix noisy "twisted.internet.task.TaskStopped" errors in logs

Fixes #4003
---
 changelog.d/4546.bugfix                |  1 +
 synapse/http/matrixfederationclient.py | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/4546.bugfix

diff --git a/changelog.d/4546.bugfix b/changelog.d/4546.bugfix
new file mode 100644
index 0000000000..056f2848ed
--- /dev/null
+++ b/changelog.d/4546.bugfix
@@ -0,0 +1 @@
+Fix noisy "twisted.internet.task.TaskStopped" errors in logs
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index bb2e64ed80..5ee4d528d2 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -28,7 +28,7 @@ from canonicaljson import encode_canonical_json
 from prometheus_client import Counter
 from signedjson.sign import sign_json
 
-from twisted.internet import defer, protocol
+from twisted.internet import defer, protocol, task
 from twisted.internet.error import DNSLookupError
 from twisted.internet.task import _EPSILON, Cooperator
 from twisted.web._newclient import ResponseDone
@@ -286,7 +286,7 @@ class MatrixFederationHttpClient(object):
                             json,
                         )
                         data = encode_canonical_json(json)
-                        producer = FileBodyProducer(
+                        producer = QuieterFileBodyProducer(
                             BytesIO(data),
                             cooperator=self._cooperator,
                         )
@@ -839,3 +839,16 @@ def encode_query_args(args):
     query_bytes = urllib.parse.urlencode(encoded_args, True)
 
     return query_bytes.encode('utf8')
+
+
+class QuieterFileBodyProducer(FileBodyProducer):
+    """Wrapper for FileBodyProducer that avoids CRITICAL errors when the connection drops.
+
+    Workaround for https://github.com/matrix-org/synapse/issues/4003 /
+    https://twistedmatrix.com/trac/ticket/6528
+    """
+    def stopProducing(self):
+        try:
+            FileBodyProducer.stopProducing(self)
+        except task.TaskStopped:
+            pass