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tests: add tests for poorly behaving HTTP server...
tests: add tests for poorly behaving HTTP server I've spent several hours over the past few weeks investigating networking failures involving hg.mozilla.org. As part of this, it has become clear that the Mercurial client's error handling when it encounters network failures is far from robust. To prove this is true, I've devised a battery of tests simulating various network failures, notably premature connection closes. To achieve this, I've implemented an extension that monkeypatches the built-in HTTP server and hooks in at the socket level and allows various events to occur based on config options. For example, you can refuse to accept() a client socket or you can close() the socket after N bytes have been sent or received. The latter effectively simulates an unexpected connection drop (and these occur all the time in the real world). The new test file launches servers exhibiting various "bad" behaviors and points a client at them. As the many TODO comments in the test call attention to, Mercurial often displays unhelpful errors when network-related failures occur. This makes it difficult for users to understand what's going on and difficult for server administrators to pinpoint root causes without packet tracing. Upcoming patches will attempt to fix these error handling deficiencies.

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httpconnection.py
297 lines | 10.6 KiB | text/x-python | PythonLexer
# httpconnection.py - urllib2 handler for new http support
#
# Copyright 2005, 2006, 2007, 2008 Matt Mackall <mpm@selenic.com>
# Copyright 2006, 2007 Alexis S. L. Carvalho <alexis@cecm.usp.br>
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
# Copyright 2011 Google, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import logging
import os
import socket
from .i18n import _
from . import (
httpclient,
sslutil,
util,
)
urlerr = util.urlerr
urlreq = util.urlreq
# moved here from url.py to avoid a cycle
class httpsendfile(object):
"""This is a wrapper around the objects returned by python's "open".
Its purpose is to send file-like objects via HTTP.
It do however not define a __len__ attribute because the length
might be more than Py_ssize_t can handle.
"""
def __init__(self, ui, *args, **kwargs):
self.ui = ui
self._data = open(*args, **kwargs)
self.seek = self._data.seek
self.close = self._data.close
self.write = self._data.write
self.length = os.fstat(self._data.fileno()).st_size
self._pos = 0
self._total = self.length // 1024 * 2
def read(self, *args, **kwargs):
ret = self._data.read(*args, **kwargs)
if not ret:
self.ui.progress(_('sending'), None)
return ret
self._pos += len(ret)
# We pass double the max for total because we currently have
# to send the bundle twice in the case of a server that
# requires authentication. Since we can't know until we try
# once whether authentication will be required, just lie to
# the user and maybe the push succeeds suddenly at 50%.
self.ui.progress(_('sending'), self._pos // 1024,
unit=_('kb'), total=self._total)
return ret
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
# moved here from url.py to avoid a cycle
def readauthforuri(ui, uri, user):
# Read configuration
groups = {}
for key, val in ui.configitems('auth'):
if key in ('cookiefile',):
continue
if '.' not in key:
ui.warn(_("ignoring invalid [auth] key '%s'\n") % key)
continue
group, setting = key.rsplit('.', 1)
gdict = groups.setdefault(group, {})
if setting in ('username', 'cert', 'key'):
val = util.expandpath(val)
gdict[setting] = val
# Find the best match
scheme, hostpath = uri.split('://', 1)
bestuser = None
bestlen = 0
bestauth = None
for group, auth in groups.iteritems():
if user and user != auth.get('username', user):
# If a username was set in the URI, the entry username
# must either match it or be unset
continue
prefix = auth.get('prefix')
if not prefix:
continue
p = prefix.split('://', 1)
if len(p) > 1:
schemes, prefix = [p[0]], p[1]
else:
schemes = (auth.get('schemes') or 'https').split()
if (prefix == '*' or hostpath.startswith(prefix)) and \
(len(prefix) > bestlen or (len(prefix) == bestlen and \
not bestuser and 'username' in auth)) \
and scheme in schemes:
bestlen = len(prefix)
bestauth = group, auth
bestuser = auth.get('username')
if user and not bestuser:
auth['username'] = user
return bestauth
# Mercurial (at least until we can remove the old codepath) requires
# that the http response object be sufficiently file-like, so we
# provide a close() method here.
class HTTPResponse(httpclient.HTTPResponse):
def close(self):
pass
class HTTPConnection(httpclient.HTTPConnection):
response_class = HTTPResponse
def request(self, method, uri, body=None, headers=None):
if headers is None:
headers = {}
if isinstance(body, httpsendfile):
body.seek(0)
httpclient.HTTPConnection.request(self, method, uri, body=body,
headers=headers)
_configuredlogging = False
LOGFMT = '%(levelname)s:%(name)s:%(lineno)d:%(message)s'
# Subclass BOTH of these because otherwise urllib2 "helpfully"
# reinserts them since it notices we don't include any subclasses of
# them.
class http2handler(urlreq.httphandler, urlreq.httpshandler):
def __init__(self, ui, pwmgr):
global _configuredlogging
urlreq.abstracthttphandler.__init__(self)
self.ui = ui
self.pwmgr = pwmgr
self._connections = {}
# developer config: ui.http2debuglevel
loglevel = ui.config('ui', 'http2debuglevel', default=None)
if loglevel and not _configuredlogging:
_configuredlogging = True
logger = logging.getLogger('mercurial.httpclient')
logger.setLevel(getattr(logging, loglevel.upper()))
handler = logging.StreamHandler()
handler.setFormatter(logging.Formatter(LOGFMT))
logger.addHandler(handler)
def close_all(self):
"""Close and remove all connection objects being kept for reuse."""
for openconns in self._connections.values():
for conn in openconns:
conn.close()
self._connections = {}
# shamelessly borrowed from urllib2.AbstractHTTPHandler
def do_open(self, http_class, req, use_ssl):
"""Return an addinfourl object for the request, using http_class.
http_class must implement the HTTPConnection API from httplib.
The addinfourl return value is a file-like object. It also
has methods and attributes including:
- info(): return a mimetools.Message object for the headers
- geturl(): return the original request URL
- code: HTTP status code
"""
# If using a proxy, the host returned by get_host() is
# actually the proxy. On Python 2.6.1, the real destination
# hostname is encoded in the URI in the urllib2 request
# object. On Python 2.6.5, it's stored in the _tunnel_host
# attribute which has no accessor.
tunhost = getattr(req, '_tunnel_host', None)
host = req.get_host()
if tunhost:
proxyhost = host
host = tunhost
elif req.has_proxy():
proxyhost = req.get_host()
host = req.get_selector().split('://', 1)[1].split('/', 1)[0]
else:
proxyhost = None
if proxyhost:
if ':' in proxyhost:
# Note: this means we'll explode if we try and use an
# IPv6 http proxy. This isn't a regression, so we
# won't worry about it for now.
proxyhost, proxyport = proxyhost.rsplit(':', 1)
else:
proxyport = 3128 # squid default
proxy = (proxyhost, proxyport)
else:
proxy = None
if not host:
raise urlerr.urlerror('no host given')
connkey = use_ssl, host, proxy
allconns = self._connections.get(connkey, [])
conns = [c for c in allconns if not c.busy()]
if conns:
h = conns[0]
else:
if allconns:
self.ui.debug('all connections for %s busy, making a new '
'one\n' % host)
timeout = None
if req.timeout is not socket._GLOBAL_DEFAULT_TIMEOUT:
timeout = req.timeout
h = http_class(host, timeout=timeout, proxy_hostport=proxy)
self._connections.setdefault(connkey, []).append(h)
headers = dict(req.headers)
headers.update(req.unredirected_hdrs)
headers = dict(
(name.title(), val) for name, val in headers.items())
try:
path = req.get_selector()
if '://' in path:
path = path.split('://', 1)[1].split('/', 1)[1]
if path[0] != '/':
path = '/' + path
h.request(req.get_method(), path, req.data, headers)
r = h.getresponse()
except socket.error as err: # XXX what error?
raise urlerr.urlerror(err)
# Pick apart the HTTPResponse object to get the addinfourl
# object initialized properly.
r.recv = r.read
resp = urlreq.addinfourl(r, r.headers, req.get_full_url())
resp.code = r.status
resp.msg = r.reason
return resp
# httplib always uses the given host/port as the socket connect
# target, and then allows full URIs in the request path, which it
# then observes and treats as a signal to do proxying instead.
def http_open(self, req):
if req.get_full_url().startswith('https'):
return self.https_open(req)
def makehttpcon(*args, **kwargs):
k2 = dict(kwargs)
k2['use_ssl'] = False
return HTTPConnection(*args, **k2)
return self.do_open(makehttpcon, req, False)
def https_open(self, req):
# req.get_full_url() does not contain credentials and we may
# need them to match the certificates.
url = req.get_full_url()
user, password = self.pwmgr.find_stored_password(url)
res = readauthforuri(self.ui, url, user)
if res:
group, auth = res
self.auth = auth
self.ui.debug("using auth.%s.* for authentication\n" % group)
else:
self.auth = None
return self.do_open(self._makesslconnection, req, True)
def _makesslconnection(self, host, port=443, *args, **kwargs):
keyfile = None
certfile = None
if args: # key_file
keyfile = args.pop(0)
if args: # cert_file
certfile = args.pop(0)
# if the user has specified different key/cert files in
# hgrc, we prefer these
if self.auth and 'key' in self.auth and 'cert' in self.auth:
keyfile = self.auth['key']
certfile = self.auth['cert']
# let host port take precedence
if ':' in host and '[' not in host or ']:' in host:
host, port = host.rsplit(':', 1)
port = int(port)
if '[' in host:
host = host[1:-1]
kwargs['keyfile'] = keyfile
kwargs['certfile'] = certfile
con = HTTPConnection(host, port, use_ssl=True,
ssl_wrap_socket=sslutil.wrapsocket,
ssl_validator=sslutil.validatesocket,
ui=self.ui,
**kwargs)
return con