##// END OF EJS Templates
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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server.py
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# hgweb/server.py - The standalone hg web server.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>
# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
#
# 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 errno
import os
import socket
import sys
import traceback
from ..i18n import _
from .. import (
error,
pycompat,
util,
)
httpservermod = util.httpserver
socketserver = util.socketserver
urlerr = util.urlerr
urlreq = util.urlreq
from . import (
common,
)
def _splitURI(uri):
"""Return path and query that has been split from uri
Just like CGI environment, the path is unquoted, the query is
not.
"""
if '?' in uri:
path, query = uri.split('?', 1)
else:
path, query = uri, ''
return urlreq.unquote(path), query
class _error_logger(object):
def __init__(self, handler):
self.handler = handler
def flush(self):
pass
def write(self, str):
self.writelines(str.split('\n'))
def writelines(self, seq):
for msg in seq:
self.handler.log_error("HG error: %s", msg)
class _httprequesthandler(httpservermod.basehttprequesthandler):
url_scheme = 'http'
@staticmethod
def preparehttpserver(httpserver, ui):
"""Prepare .socket of new HTTPServer instance"""
pass
def __init__(self, *args, **kargs):
self.protocol_version = 'HTTP/1.1'
httpservermod.basehttprequesthandler.__init__(self, *args, **kargs)
def _log_any(self, fp, format, *args):
fp.write("%s - - [%s] %s\n" % (self.client_address[0],
self.log_date_time_string(),
format % args))
fp.flush()
def log_error(self, format, *args):
self._log_any(self.server.errorlog, format, *args)
def log_message(self, format, *args):
self._log_any(self.server.accesslog, format, *args)
def log_request(self, code='-', size='-'):
xheaders = []
if util.safehasattr(self, 'headers'):
xheaders = [h for h in self.headers.items()
if h[0].startswith('x-')]
self.log_message('"%s" %s %s%s',
self.requestline, str(code), str(size),
''.join([' %s:%s' % h for h in sorted(xheaders)]))
def do_write(self):
try:
self.do_hgweb()
except socket.error as inst:
if inst[0] != errno.EPIPE:
raise
def do_POST(self):
try:
self.do_write()
except Exception:
self._start_response("500 Internal Server Error", [])
self._write("Internal Server Error")
self._done()
tb = "".join(traceback.format_exception(*sys.exc_info()))
self.log_error("Exception happened during processing "
"request '%s':\n%s", self.path, tb)
def do_GET(self):
self.do_POST()
def do_hgweb(self):
path, query = _splitURI(self.path)
env = {}
env['GATEWAY_INTERFACE'] = 'CGI/1.1'
env['REQUEST_METHOD'] = self.command
env['SERVER_NAME'] = self.server.server_name
env['SERVER_PORT'] = str(self.server.server_port)
env['REQUEST_URI'] = self.path
env['SCRIPT_NAME'] = self.server.prefix
env['PATH_INFO'] = path[len(self.server.prefix):]
env['REMOTE_HOST'] = self.client_address[0]
env['REMOTE_ADDR'] = self.client_address[0]
if query:
env['QUERY_STRING'] = query
if self.headers.typeheader is None:
env['CONTENT_TYPE'] = self.headers.type
else:
env['CONTENT_TYPE'] = self.headers.typeheader
length = self.headers.getheader('content-length')
if length:
env['CONTENT_LENGTH'] = length
for header in [h for h in self.headers.keys()
if h not in ('content-type', 'content-length')]:
hkey = 'HTTP_' + header.replace('-', '_').upper()
hval = self.headers.getheader(header)
hval = hval.replace('\n', '').strip()
if hval:
env[hkey] = hval
env['SERVER_PROTOCOL'] = self.request_version
env['wsgi.version'] = (1, 0)
env['wsgi.url_scheme'] = self.url_scheme
if env.get('HTTP_EXPECT', '').lower() == '100-continue':
self.rfile = common.continuereader(self.rfile, self.wfile.write)
env['wsgi.input'] = self.rfile
env['wsgi.errors'] = _error_logger(self)
env['wsgi.multithread'] = isinstance(self.server,
socketserver.ThreadingMixIn)
env['wsgi.multiprocess'] = isinstance(self.server,
socketserver.ForkingMixIn)
env['wsgi.run_once'] = 0
self.saved_status = None
self.saved_headers = []
self.sent_headers = False
self.length = None
self._chunked = None
for chunk in self.server.application(env, self._start_response):
self._write(chunk)
if not self.sent_headers:
self.send_headers()
self._done()
def send_headers(self):
if not self.saved_status:
raise AssertionError("Sending headers before "
"start_response() called")
saved_status = self.saved_status.split(None, 1)
saved_status[0] = int(saved_status[0])
self.send_response(*saved_status)
self.length = None
self._chunked = False
for h in self.saved_headers:
self.send_header(*h)
if h[0].lower() == 'content-length':
self.length = int(h[1])
if (self.length is None and
saved_status[0] != common.HTTP_NOT_MODIFIED):
self._chunked = (not self.close_connection and
self.request_version == "HTTP/1.1")
if self._chunked:
self.send_header('Transfer-Encoding', 'chunked')
else:
self.send_header('Connection', 'close')
self.end_headers()
self.sent_headers = True
def _start_response(self, http_status, headers, exc_info=None):
code, msg = http_status.split(None, 1)
code = int(code)
self.saved_status = http_status
bad_headers = ('connection', 'transfer-encoding')
self.saved_headers = [h for h in headers
if h[0].lower() not in bad_headers]
return self._write
def _write(self, data):
if not self.saved_status:
raise AssertionError("data written before start_response() called")
elif not self.sent_headers:
self.send_headers()
if self.length is not None:
if len(data) > self.length:
raise AssertionError("Content-length header sent, but more "
"bytes than specified are being written.")
self.length = self.length - len(data)
elif self._chunked and data:
data = '%x\r\n%s\r\n' % (len(data), data)
self.wfile.write(data)
self.wfile.flush()
def _done(self):
if self._chunked:
self.wfile.write('0\r\n\r\n')
self.wfile.flush()
class _httprequesthandlerssl(_httprequesthandler):
"""HTTPS handler based on Python's ssl module"""
url_scheme = 'https'
@staticmethod
def preparehttpserver(httpserver, ui):
try:
from .. import sslutil
sslutil.modernssl
except ImportError:
raise error.Abort(_("SSL support is unavailable"))
certfile = ui.config('web', 'certificate')
# These config options are currently only meant for testing. Use
# at your own risk.
cafile = ui.config('devel', 'servercafile')
reqcert = ui.configbool('devel', 'serverrequirecert')
httpserver.socket = sslutil.wrapserversocket(httpserver.socket,
ui,
certfile=certfile,
cafile=cafile,
requireclientcert=reqcert)
def setup(self):
self.connection = self.request
self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)
try:
import threading
threading.activeCount() # silence pyflakes and bypass demandimport
_mixin = socketserver.ThreadingMixIn
except ImportError:
if util.safehasattr(os, "fork"):
_mixin = socketserver.ForkingMixIn
else:
class _mixin(object):
pass
def openlog(opt, default):
if opt and opt != '-':
return open(opt, 'a')
return default
class MercurialHTTPServer(_mixin, httpservermod.httpserver, object):
# SO_REUSEADDR has broken semantics on windows
if pycompat.osname == 'nt':
allow_reuse_address = 0
def __init__(self, ui, app, addr, handler, **kwargs):
httpservermod.httpserver.__init__(self, addr, handler, **kwargs)
self.daemon_threads = True
self.application = app
handler.preparehttpserver(self, ui)
prefix = ui.config('web', 'prefix', '')
if prefix:
prefix = '/' + prefix.strip('/')
self.prefix = prefix
alog = openlog(ui.config('web', 'accesslog', '-'), ui.fout)
elog = openlog(ui.config('web', 'errorlog', '-'), ui.ferr)
self.accesslog = alog
self.errorlog = elog
self.addr, self.port = self.socket.getsockname()[0:2]
self.fqaddr = socket.getfqdn(addr[0])
class IPv6HTTPServer(MercurialHTTPServer):
address_family = getattr(socket, 'AF_INET6', None)
def __init__(self, *args, **kwargs):
if self.address_family is None:
raise error.RepoError(_('IPv6 is not available on this system'))
super(IPv6HTTPServer, self).__init__(*args, **kwargs)
def create_server(ui, app):
if ui.config('web', 'certificate'):
handler = _httprequesthandlerssl
else:
handler = _httprequesthandler
if ui.configbool('web', 'ipv6'):
cls = IPv6HTTPServer
else:
cls = MercurialHTTPServer
# ugly hack due to python issue5853 (for threaded use)
try:
import mimetypes
mimetypes.init()
except UnicodeDecodeError:
# Python 2.x's mimetypes module attempts to decode strings
# from Windows' ANSI APIs as ascii (fail), then re-encode them
# as ascii (clown fail), because the default Python Unicode
# codec is hardcoded as ascii.
sys.argv # unwrap demand-loader so that reload() works
reload(sys) # resurrect sys.setdefaultencoding()
oldenc = sys.getdefaultencoding()
sys.setdefaultencoding("latin1") # or any full 8-bit encoding
mimetypes.init()
sys.setdefaultencoding(oldenc)
address = ui.config('web', 'address', '')
port = util.getport(ui.config('web', 'port', 8000))
try:
return cls(ui, app, (address, port), handler)
except socket.error as inst:
raise error.Abort(_("cannot start server at '%s:%d': %s")
% (address, port, inst.args[1]))