Convert the well known resolver to async (#8214)

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Patrick Cloke 2020-09-01 09:15:22 -04:00 committed by GitHub
parent da77520cd1
commit 5bf8e5f55b
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5 changed files with 53 additions and 34 deletions

1
changelog.d/8214.misc Normal file
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@ -0,0 +1 @@
Convert various parts of the codebase to async/await.

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@ -28,6 +28,7 @@ files =
synapse/handlers/saml_handler.py,
synapse/handlers/sync.py,
synapse/handlers/ui_auth,
synapse/http/federation/well_known_resolver.py,
synapse/http/server.py,
synapse/http/site.py,
synapse/logging/,

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@ -134,8 +134,8 @@ class MatrixFederationAgent(object):
and not _is_ip_literal(parsed_uri.hostname)
and not parsed_uri.port
):
well_known_result = yield self._well_known_resolver.get_well_known(
parsed_uri.hostname
well_known_result = yield defer.ensureDeferred(
self._well_known_resolver.get_well_known(parsed_uri.hostname)
)
delegated_server = well_known_result.delegated_server

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@ -16,6 +16,7 @@
import logging
import random
import time
from typing import Callable, Dict, Optional, Tuple
import attr
@ -23,6 +24,7 @@ from twisted.internet import defer
from twisted.web.client import RedirectAgent, readBody
from twisted.web.http import stringToDatetime
from twisted.web.http_headers import Headers
from twisted.web.iweb import IResponse
from synapse.logging.context import make_deferred_yieldable
from synapse.util import Clock, json_decoder
@ -99,15 +101,14 @@ class WellKnownResolver(object):
self._well_known_agent = RedirectAgent(agent)
self.user_agent = user_agent
@defer.inlineCallbacks
def get_well_known(self, server_name):
async def get_well_known(self, server_name: bytes) -> WellKnownLookupResult:
"""Attempt to fetch and parse a .well-known file for the given server
Args:
server_name (bytes): name of the server, from the requested url
server_name: name of the server, from the requested url
Returns:
Deferred[WellKnownLookupResult]: The result of the lookup
The result of the lookup
"""
try:
prev_result, expiry, ttl = self._well_known_cache.get_with_expiry(
@ -124,7 +125,9 @@ class WellKnownResolver(object):
# requests for the same server in parallel?
try:
with Measure(self._clock, "get_well_known"):
result, cache_period = yield self._fetch_well_known(server_name)
result, cache_period = await self._fetch_well_known(
server_name
) # type: Tuple[Optional[bytes], float]
except _FetchWellKnownFailure as e:
if prev_result and e.temporary:
@ -153,18 +156,17 @@ class WellKnownResolver(object):
return WellKnownLookupResult(delegated_server=result)
@defer.inlineCallbacks
def _fetch_well_known(self, server_name):
async def _fetch_well_known(self, server_name: bytes) -> Tuple[bytes, float]:
"""Actually fetch and parse a .well-known, without checking the cache
Args:
server_name (bytes): name of the server, from the requested url
server_name: name of the server, from the requested url
Raises:
_FetchWellKnownFailure if we fail to lookup a result
Returns:
Deferred[Tuple[bytes,int]]: The lookup result and cache period.
The lookup result and cache period.
"""
had_valid_well_known = self._had_valid_well_known_cache.get(server_name, False)
@ -172,7 +174,7 @@ class WellKnownResolver(object):
# We do this in two steps to differentiate between possibly transient
# errors (e.g. can't connect to host, 503 response) and more permenant
# errors (such as getting a 404 response).
response, body = yield self._make_well_known_request(
response, body = await self._make_well_known_request(
server_name, retry=had_valid_well_known
)
@ -215,20 +217,20 @@ class WellKnownResolver(object):
return result, cache_period
@defer.inlineCallbacks
def _make_well_known_request(self, server_name, retry):
async def _make_well_known_request(
self, server_name: bytes, retry: bool
) -> Tuple[IResponse, bytes]:
"""Make the well known request.
This will retry the request if requested and it fails (with unable
to connect or receives a 5xx error).
Args:
server_name (bytes)
retry (bool): Whether to retry the request if it fails.
server_name: name of the server, from the requested url
retry: Whether to retry the request if it fails.
Returns:
Deferred[tuple[IResponse, bytes]] Returns the response object and
body. Response may be a non-200 response.
Returns the response object and body. Response may be a non-200 response.
"""
uri = b"https://%s/.well-known/matrix/server" % (server_name,)
uri_str = uri.decode("ascii")
@ -243,12 +245,12 @@ class WellKnownResolver(object):
logger.info("Fetching %s", uri_str)
try:
response = yield make_deferred_yieldable(
response = await make_deferred_yieldable(
self._well_known_agent.request(
b"GET", uri, headers=Headers(headers)
)
)
body = yield make_deferred_yieldable(readBody(response))
body = await make_deferred_yieldable(readBody(response))
if 500 <= response.code < 600:
raise Exception("Non-200 response %s" % (response.code,))
@ -265,19 +267,22 @@ class WellKnownResolver(object):
logger.info("Error fetching %s: %s. Retrying", uri_str, e)
# Sleep briefly in the hopes that they come back up
yield self._clock.sleep(0.5)
await self._clock.sleep(0.5)
def _cache_period_from_headers(headers, time_now=time.time):
def _cache_period_from_headers(
headers: Headers, time_now: Callable[[], float] = time.time
) -> Optional[float]:
cache_controls = _parse_cache_control(headers)
if b"no-store" in cache_controls:
return 0
if b"max-age" in cache_controls:
max_age = cache_controls[b"max-age"]
if max_age:
try:
max_age = int(cache_controls[b"max-age"])
return max_age
return int(max_age)
except ValueError:
pass
@ -295,7 +300,7 @@ def _cache_period_from_headers(headers, time_now=time.time):
return None
def _parse_cache_control(headers):
def _parse_cache_control(headers: Headers) -> Dict[bytes, Optional[bytes]]:
cache_controls = {}
for hdr in headers.getRawHeaders(b"cache-control", []):
for directive in hdr.split(b","):

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@ -972,7 +972,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
def test_well_known_cache(self):
self.reactor.lookups["testserv"] = "1.2.3.4"
fetch_d = self.well_known_resolver.get_well_known(b"testserv")
fetch_d = defer.ensureDeferred(
self.well_known_resolver.get_well_known(b"testserv")
)
# there should be an attempt to connect on port 443 for the .well-known
clients = self.reactor.tcpClients
@ -995,7 +997,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
well_known_server.loseConnection()
# repeat the request: it should hit the cache
fetch_d = self.well_known_resolver.get_well_known(b"testserv")
fetch_d = defer.ensureDeferred(
self.well_known_resolver.get_well_known(b"testserv")
)
r = self.successResultOf(fetch_d)
self.assertEqual(r.delegated_server, b"target-server")
@ -1003,7 +1007,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
self.reactor.pump((1000.0,))
# now it should connect again
fetch_d = self.well_known_resolver.get_well_known(b"testserv")
fetch_d = defer.ensureDeferred(
self.well_known_resolver.get_well_known(b"testserv")
)
self.assertEqual(len(clients), 1)
(host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
@ -1026,7 +1032,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
self.reactor.lookups["testserv"] = "1.2.3.4"
fetch_d = self.well_known_resolver.get_well_known(b"testserv")
fetch_d = defer.ensureDeferred(
self.well_known_resolver.get_well_known(b"testserv")
)
# there should be an attempt to connect on port 443 for the .well-known
clients = self.reactor.tcpClients
@ -1052,7 +1060,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
# another lookup.
self.reactor.pump((900.0,))
fetch_d = self.well_known_resolver.get_well_known(b"testserv")
fetch_d = defer.ensureDeferred(
self.well_known_resolver.get_well_known(b"testserv")
)
# The resolver may retry a few times, so fonx all requests that come along
attempts = 0
@ -1082,7 +1092,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
self.reactor.pump((10000.0,))
# Repated the request, this time it should fail if the lookup fails.
fetch_d = self.well_known_resolver.get_well_known(b"testserv")
fetch_d = defer.ensureDeferred(
self.well_known_resolver.get_well_known(b"testserv")
)
clients = self.reactor.tcpClients
(host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)