synapse-product/synapse/http/matrixfederationclient.py
Erik Johnston b970cb0e96 Refactor request sending to have better excpetions (#4358)
* Correctly retry and back off if we get a HTTPerror response

* Refactor request sending to have better excpetions

MatrixFederationHttpClient blindly reraised exceptions to the caller
without differentiating "expected" failures (e.g. connection timeouts
etc) versus more severe problems (e.g. programming errors).

This commit adds a RequestSendFailed exception that is raised when
"expected" failures happen, allowing the TransactionQueue to log them as
warnings while allowing us to log other exceptions as actual exceptions.
2019-01-08 11:04:28 +00:00

856 lines
29 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2018 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import cgi
import logging
import random
import sys
from io import BytesIO
from six import PY3, raise_from, string_types
from six.moves import urllib
import attr
import treq
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.error import DNSLookupError
from twisted.internet.task import _EPSILON, Cooperator
from twisted.web._newclient import ResponseDone
from twisted.web.client import Agent, FileBodyProducer, HTTPConnectionPool
from twisted.web.http_headers import Headers
import synapse.metrics
import synapse.util.retryutils
from synapse.api.errors import (
Codes,
FederationDeniedError,
HttpResponseException,
RequestSendFailed,
SynapseError,
)
from synapse.http.endpoint import matrix_federation_endpoint
from synapse.util.async_helpers import timeout_deferred
from synapse.util.logcontext import make_deferred_yieldable
from synapse.util.metrics import Measure
logger = logging.getLogger(__name__)
outgoing_requests_counter = Counter("synapse_http_matrixfederationclient_requests",
"", ["method"])
incoming_responses_counter = Counter("synapse_http_matrixfederationclient_responses",
"", ["method", "code"])
MAX_LONG_RETRIES = 10
MAX_SHORT_RETRIES = 3
if PY3:
MAXINT = sys.maxsize
else:
MAXINT = sys.maxint
class MatrixFederationEndpointFactory(object):
def __init__(self, hs):
self.reactor = hs.get_reactor()
self.tls_client_options_factory = hs.tls_client_options_factory
def endpointForURI(self, uri):
destination = uri.netloc.decode('ascii')
return matrix_federation_endpoint(
self.reactor, destination, timeout=10,
tls_client_options_factory=self.tls_client_options_factory
)
_next_id = 1
@attr.s
class MatrixFederationRequest(object):
method = attr.ib()
"""HTTP method
:type: str
"""
path = attr.ib()
"""HTTP path
:type: str
"""
destination = attr.ib()
"""The remote server to send the HTTP request to.
:type: str"""
json = attr.ib(default=None)
"""JSON to send in the body.
:type: dict|None
"""
json_callback = attr.ib(default=None)
"""A callback to generate the JSON.
:type: func|None
"""
query = attr.ib(default=None)
"""Query arguments.
:type: dict|None
"""
txn_id = attr.ib(default=None)
"""Unique ID for this request (for logging)
:type: str|None
"""
def __attrs_post_init__(self):
global _next_id
self.txn_id = "%s-O-%s" % (self.method, _next_id)
_next_id = (_next_id + 1) % (MAXINT - 1)
def get_json(self):
if self.json_callback:
return self.json_callback()
return self.json
@defer.inlineCallbacks
def _handle_json_response(reactor, timeout_sec, request, response):
"""
Reads the JSON body of a response, with a timeout
Args:
reactor (IReactor): twisted reactor, for the timeout
timeout_sec (float): number of seconds to wait for response to complete
request (MatrixFederationRequest): the request that triggered the response
response (IResponse): response to the request
Returns:
dict: parsed JSON response
"""
try:
check_content_type_is_json(response.headers)
d = treq.json_content(response)
d = timeout_deferred(
d,
timeout=timeout_sec,
reactor=reactor,
)
body = yield make_deferred_yieldable(d)
except Exception as e:
logger.warn(
"{%s} [%s] Error reading response: %s",
request.txn_id,
request.destination,
e,
)
raise
logger.info(
"{%s} [%s] Completed: %d %s",
request.txn_id,
request.destination,
response.code,
response.phrase.decode('ascii', errors='replace'),
)
defer.returnValue(body)
class MatrixFederationHttpClient(object):
"""HTTP client used to talk to other homeservers over the federation
protocol. Send client certificates and signs requests.
Attributes:
agent (twisted.web.client.Agent): The twisted Agent used to send the
requests.
"""
def __init__(self, hs):
self.hs = hs
self.signing_key = hs.config.signing_key[0]
self.server_name = hs.hostname
reactor = hs.get_reactor()
pool = HTTPConnectionPool(reactor)
pool.retryAutomatically = False
pool.maxPersistentPerHost = 5
pool.cachedConnectionTimeout = 2 * 60
self.agent = Agent.usingEndpointFactory(
reactor, MatrixFederationEndpointFactory(hs), pool=pool
)
self.clock = hs.get_clock()
self._store = hs.get_datastore()
self.version_string_bytes = hs.version_string.encode('ascii')
self.default_timeout = 60
def schedule(x):
reactor.callLater(_EPSILON, x)
self._cooperator = Cooperator(scheduler=schedule)
@defer.inlineCallbacks
def _send_request(
self,
request,
retry_on_dns_fail=True,
timeout=None,
long_retries=False,
ignore_backoff=False,
backoff_on_404=False
):
"""
Sends a request to the given server.
Args:
request (MatrixFederationRequest): details of request to be sent
timeout (int|None): number of milliseconds to wait for the response headers
(including connecting to the server). 60s by default.
ignore_backoff (bool): true to ignore the historical backoff data
and try the request anyway.
backoff_on_404 (bool): Back off if we get a 404
Returns:
Deferred: resolves with the http response object on success.
Fails with ``HttpResponseException``: if we get an HTTP response
code >= 300 (except 429).
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
Fails with ``RequestSendFailed`` if there were problems connecting to
the remote, due to e.g. DNS failures, connection timeouts etc.
"""
if timeout:
_sec_timeout = timeout / 1000
else:
_sec_timeout = self.default_timeout
if (
self.hs.config.federation_domain_whitelist is not None and
request.destination not in self.hs.config.federation_domain_whitelist
):
raise FederationDeniedError(request.destination)
limiter = yield synapse.util.retryutils.get_retry_limiter(
request.destination,
self.clock,
self._store,
backoff_on_404=backoff_on_404,
ignore_backoff=ignore_backoff,
)
method_bytes = request.method.encode("ascii")
destination_bytes = request.destination.encode("ascii")
path_bytes = request.path.encode("ascii")
if request.query:
query_bytes = encode_query_args(request.query)
else:
query_bytes = b""
headers_dict = {
b"User-Agent": [self.version_string_bytes],
b"Host": [destination_bytes],
}
with limiter:
# XXX: Would be much nicer to retry only at the transaction-layer
# (once we have reliable transactions in place)
if long_retries:
retries_left = MAX_LONG_RETRIES
else:
retries_left = MAX_SHORT_RETRIES
url_bytes = urllib.parse.urlunparse((
b"matrix", destination_bytes,
path_bytes, None, query_bytes, b"",
))
url_str = url_bytes.decode('ascii')
url_to_sign_bytes = urllib.parse.urlunparse((
b"", b"",
path_bytes, None, query_bytes, b"",
))
while True:
try:
json = request.get_json()
if json:
headers_dict[b"Content-Type"] = [b"application/json"]
self.sign_request(
destination_bytes, method_bytes, url_to_sign_bytes,
headers_dict, json,
)
data = encode_canonical_json(json)
producer = FileBodyProducer(
BytesIO(data),
cooperator=self._cooperator,
)
else:
producer = None
self.sign_request(
destination_bytes, method_bytes, url_to_sign_bytes,
headers_dict,
)
logger.info(
"{%s} [%s] Sending request: %s %s",
request.txn_id, request.destination, request.method,
url_str,
)
# we don't want all the fancy cookie and redirect handling that
# treq.request gives: just use the raw Agent.
request_deferred = self.agent.request(
method_bytes,
url_bytes,
headers=Headers(headers_dict),
bodyProducer=producer,
)
request_deferred = timeout_deferred(
request_deferred,
timeout=_sec_timeout,
reactor=self.hs.get_reactor(),
)
try:
with Measure(self.clock, "outbound_request"):
response = yield make_deferred_yieldable(
request_deferred,
)
except DNSLookupError as e:
raise_from(RequestSendFailed(e, can_retry=retry_on_dns_fail), e)
except Exception as e:
raise_from(RequestSendFailed(e, can_retry=True), e)
logger.info(
"{%s} [%s] Got response headers: %d %s",
request.txn_id,
request.destination,
response.code,
response.phrase.decode('ascii', errors='replace'),
)
if 200 <= response.code < 300:
pass
else:
# :'(
# Update transactions table?
d = treq.content(response)
d = timeout_deferred(
d,
timeout=_sec_timeout,
reactor=self.hs.get_reactor(),
)
try:
body = yield make_deferred_yieldable(d)
except Exception as e:
# Eh, we're already going to raise an exception so lets
# ignore if this fails.
logger.warn(
"{%s} [%s] Failed to get error response: %s %s: %s",
request.txn_id,
request.destination,
request.method,
url_str,
_flatten_response_never_received(e),
)
body = None
e = HttpResponseException(
response.code, response.phrase, body
)
# Retry if the error is a 429 (Too Many Requests),
# otherwise just raise a standard HttpResponseException
if response.code == 429:
raise_from(RequestSendFailed(e, can_retry=True), e)
else:
raise e
break
except RequestSendFailed as e:
logger.warn(
"{%s} [%s] Request failed: %s %s: %s",
request.txn_id,
request.destination,
request.method,
url_str,
_flatten_response_never_received(e.inner_exception),
)
if not e.can_retry:
raise
if retries_left and not timeout:
if long_retries:
delay = 4 ** (MAX_LONG_RETRIES + 1 - retries_left)
delay = min(delay, 60)
delay *= random.uniform(0.8, 1.4)
else:
delay = 0.5 * 2 ** (MAX_SHORT_RETRIES - retries_left)
delay = min(delay, 2)
delay *= random.uniform(0.8, 1.4)
logger.debug(
"{%s} [%s] Waiting %ss before re-sending...",
request.txn_id,
request.destination,
delay,
)
yield self.clock.sleep(delay)
retries_left -= 1
else:
raise
except Exception as e:
logger.warn(
"{%s} [%s] Request failed: %s %s: %s",
request.txn_id,
request.destination,
request.method,
url_str,
_flatten_response_never_received(e),
)
raise
defer.returnValue(response)
def sign_request(self, destination, method, url_bytes, headers_dict,
content=None, destination_is=None):
"""
Signs a request by adding an Authorization header to headers_dict
Args:
destination (bytes|None): The desination home server of the request.
May be None if the destination is an identity server, in which case
destination_is must be non-None.
method (bytes): The HTTP method of the request
url_bytes (bytes): The URI path of the request
headers_dict (dict[bytes, list[bytes]]): Dictionary of request headers to
append to
content (object): The body of the request
destination_is (bytes): As 'destination', but if the destination is an
identity server
Returns:
None
"""
request = {
"method": method,
"uri": url_bytes,
"origin": self.server_name,
}
if destination is not None:
request["destination"] = destination
if destination_is is not None:
request["destination_is"] = destination_is
if content is not None:
request["content"] = content
request = sign_json(request, self.server_name, self.signing_key)
auth_headers = []
for key, sig in request["signatures"][self.server_name].items():
auth_headers.append((
"X-Matrix origin=%s,key=\"%s\",sig=\"%s\"" % (
self.server_name, key, sig,
)).encode('ascii')
)
headers_dict[b"Authorization"] = auth_headers
@defer.inlineCallbacks
def put_json(self, destination, path, args={}, data={},
json_data_callback=None,
long_retries=False, timeout=None,
ignore_backoff=False,
backoff_on_404=False):
""" Sends the specifed json data using PUT
Args:
destination (str): The remote server to send the HTTP request
to.
path (str): The HTTP path.
args (dict): query params
data (dict): A dict containing the data that will be used as
the request body. This will be encoded as JSON.
json_data_callback (callable): A callable returning the dict to
use as the request body.
long_retries (bool): A boolean that indicates whether we should
retry for a short or long time.
timeout(int): How long to try (in ms) the destination for before
giving up. None indicates no timeout.
ignore_backoff (bool): true to ignore the historical backoff data
and try the request anyway.
backoff_on_404 (bool): True if we should count a 404 response as
a failure of the server (and should therefore back off future
requests)
Returns:
Deferred: Succeeds when we get a 2xx HTTP response. The result
will be the decoded JSON body.
Fails with ``HttpResponseException`` if we get an HTTP response
code >= 300.
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
request = MatrixFederationRequest(
method="PUT",
destination=destination,
path=path,
query=args,
json_callback=json_data_callback,
json=data,
)
response = yield self._send_request(
request,
long_retries=long_retries,
timeout=timeout,
ignore_backoff=ignore_backoff,
backoff_on_404=backoff_on_404,
)
body = yield _handle_json_response(
self.hs.get_reactor(), self.default_timeout, request, response,
)
defer.returnValue(body)
@defer.inlineCallbacks
def post_json(self, destination, path, data={}, long_retries=False,
timeout=None, ignore_backoff=False, args={}):
""" Sends the specifed json data using POST
Args:
destination (str): The remote server to send the HTTP request
to.
path (str): The HTTP path.
data (dict): A dict containing the data that will be used as
the request body. This will be encoded as JSON.
long_retries (bool): A boolean that indicates whether we should
retry for a short or long time.
timeout(int): How long to try (in ms) the destination for before
giving up. None indicates no timeout.
ignore_backoff (bool): true to ignore the historical backoff data and
try the request anyway.
args (dict): query params
Returns:
Deferred: Succeeds when we get a 2xx HTTP response. The result
will be the decoded JSON body.
Fails with ``HttpResponseException`` if we get an HTTP response
code >= 300.
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
request = MatrixFederationRequest(
method="POST",
destination=destination,
path=path,
query=args,
json=data,
)
response = yield self._send_request(
request,
long_retries=long_retries,
timeout=timeout,
ignore_backoff=ignore_backoff,
)
if timeout:
_sec_timeout = timeout / 1000
else:
_sec_timeout = self.default_timeout
body = yield _handle_json_response(
self.hs.get_reactor(), _sec_timeout, request, response,
)
defer.returnValue(body)
@defer.inlineCallbacks
def get_json(self, destination, path, args=None, retry_on_dns_fail=True,
timeout=None, ignore_backoff=False):
""" GETs some json from the given host homeserver and path
Args:
destination (str): The remote server to send the HTTP request
to.
path (str): The HTTP path.
args (dict|None): A dictionary used to create query strings, defaults to
None.
timeout (int): How long to try (in ms) the destination for before
giving up. None indicates no timeout and that the request will
be retried.
ignore_backoff (bool): true to ignore the historical backoff data
and try the request anyway.
Returns:
Deferred: Succeeds when we get a 2xx HTTP response. The result
will be the decoded JSON body.
Fails with ``HttpResponseException`` if we get an HTTP response
code >= 300.
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
logger.debug("get_json args: %s", args)
logger.debug("Query bytes: %s Retry DNS: %s", args, retry_on_dns_fail)
request = MatrixFederationRequest(
method="GET",
destination=destination,
path=path,
query=args,
)
response = yield self._send_request(
request,
retry_on_dns_fail=retry_on_dns_fail,
timeout=timeout,
ignore_backoff=ignore_backoff,
)
body = yield _handle_json_response(
self.hs.get_reactor(), self.default_timeout, request, response,
)
defer.returnValue(body)
@defer.inlineCallbacks
def delete_json(self, destination, path, long_retries=False,
timeout=None, ignore_backoff=False, args={}):
"""Send a DELETE request to the remote expecting some json response
Args:
destination (str): The remote server to send the HTTP request
to.
path (str): The HTTP path.
long_retries (bool): A boolean that indicates whether we should
retry for a short or long time.
timeout(int): How long to try (in ms) the destination for before
giving up. None indicates no timeout.
ignore_backoff (bool): true to ignore the historical backoff data and
try the request anyway.
Returns:
Deferred: Succeeds when we get a 2xx HTTP response. The result
will be the decoded JSON body.
Fails with ``HttpResponseException`` if we get an HTTP response
code >= 300.
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
request = MatrixFederationRequest(
method="DELETE",
destination=destination,
path=path,
query=args,
)
response = yield self._send_request(
request,
long_retries=long_retries,
timeout=timeout,
ignore_backoff=ignore_backoff,
)
body = yield _handle_json_response(
self.hs.get_reactor(), self.default_timeout, request, response,
)
defer.returnValue(body)
@defer.inlineCallbacks
def get_file(self, destination, path, output_stream, args={},
retry_on_dns_fail=True, max_size=None,
ignore_backoff=False):
"""GETs a file from a given homeserver
Args:
destination (str): The remote server to send the HTTP request to.
path (str): The HTTP path to GET.
output_stream (file): File to write the response body to.
args (dict): Optional dictionary used to create the query string.
ignore_backoff (bool): true to ignore the historical backoff data
and try the request anyway.
Returns:
Deferred: resolves with an (int,dict) tuple of the file length and
a dict of the response headers.
Fails with ``HttpResponseException`` if we get an HTTP response code
>= 300
Fails with ``NotRetryingDestination`` if we are not yet ready
to retry this server.
Fails with ``FederationDeniedError`` if this destination
is not on our federation whitelist
"""
request = MatrixFederationRequest(
method="GET",
destination=destination,
path=path,
query=args,
)
response = yield self._send_request(
request,
retry_on_dns_fail=retry_on_dns_fail,
ignore_backoff=ignore_backoff,
)
headers = dict(response.headers.getAllRawHeaders())
try:
d = _readBodyToFile(response, output_stream, max_size)
d.addTimeout(self.default_timeout, self.hs.get_reactor())
length = yield make_deferred_yieldable(d)
except Exception as e:
logger.warn(
"{%s} [%s] Error reading response: %s",
request.txn_id,
request.destination,
e,
)
raise
logger.info(
"{%s} [%s] Completed: %d %s [%d bytes]",
request.txn_id,
request.destination,
response.code,
response.phrase.decode('ascii', errors='replace'),
length,
)
defer.returnValue((length, headers))
class _ReadBodyToFileProtocol(protocol.Protocol):
def __init__(self, stream, deferred, max_size):
self.stream = stream
self.deferred = deferred
self.length = 0
self.max_size = max_size
def dataReceived(self, data):
self.stream.write(data)
self.length += len(data)
if self.max_size is not None and self.length >= self.max_size:
self.deferred.errback(SynapseError(
502,
"Requested file is too large > %r bytes" % (self.max_size,),
Codes.TOO_LARGE,
))
self.deferred = defer.Deferred()
self.transport.loseConnection()
def connectionLost(self, reason):
if reason.check(ResponseDone):
self.deferred.callback(self.length)
else:
self.deferred.errback(reason)
def _readBodyToFile(response, stream, max_size):
d = defer.Deferred()
response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
return d
def _flatten_response_never_received(e):
if hasattr(e, "reasons"):
reasons = ", ".join(
_flatten_response_never_received(f.value)
for f in e.reasons
)
return "%s:[%s]" % (type(e).__name__, reasons)
else:
return repr(e)
def check_content_type_is_json(headers):
"""
Check that a set of HTTP headers have a Content-Type header, and that it
is application/json.
Args:
headers (twisted.web.http_headers.Headers): headers to check
Raises:
RuntimeError if the
"""
c_type = headers.getRawHeaders(b"Content-Type")
if c_type is None:
raise RuntimeError(
"No Content-Type header"
)
c_type = c_type[0].decode('ascii') # only the first header
val, options = cgi.parse_header(c_type)
if val != "application/json":
raise RuntimeError(
"Content-Type not application/json: was '%s'" % c_type
)
def encode_query_args(args):
if args is None:
return b""
encoded_args = {}
for k, vs in args.items():
if isinstance(vs, string_types):
vs = [vs]
encoded_args[k] = [v.encode("UTF-8") for v in vs]
query_bytes = urllib.parse.urlencode(encoded_args, True)
return query_bytes.encode('utf8')