discovery: test coverage for issue4438 / 86c35b7ae300 / 73cfaa348650
The randomness in the discovery protocol made this problem hard to reproduce.
The test mocks random.sample to make sure we hit the problem every time. The
set iteration order also made the output unstable ... but with the issue fixed,
it is stable.
# commandserver.py - communicate with Mercurial's API over a pipe
#
# Copyright 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 i18n import _
import struct
import sys, os, errno, traceback, SocketServer
import dispatch, encoding, util
logfile = None
def log(*args):
if not logfile:
return
for a in args:
logfile.write(str(a))
logfile.flush()
class channeledoutput(object):
"""
Write data to out in the following format:
data length (unsigned int),
data
"""
def __init__(self, out, channel):
self.out = out
self.channel = channel
def write(self, data):
if not data:
return
self.out.write(struct.pack('>cI', self.channel, len(data)))
self.out.write(data)
self.out.flush()
def __getattr__(self, attr):
if attr in ('isatty', 'fileno'):
raise AttributeError(attr)
return getattr(self.out, attr)
class channeledinput(object):
"""
Read data from in_.
Requests for input are written to out in the following format:
channel identifier - 'I' for plain input, 'L' line based (1 byte)
how many bytes to send at most (unsigned int),
The client replies with:
data length (unsigned int), 0 meaning EOF
data
"""
maxchunksize = 4 * 1024
def __init__(self, in_, out, channel):
self.in_ = in_
self.out = out
self.channel = channel
def read(self, size=-1):
if size < 0:
# if we need to consume all the clients input, ask for 4k chunks
# so the pipe doesn't fill up risking a deadlock
size = self.maxchunksize
s = self._read(size, self.channel)
buf = s
while s:
s = self._read(size, self.channel)
buf += s
return buf
else:
return self._read(size, self.channel)
def _read(self, size, channel):
if not size:
return ''
assert size > 0
# tell the client we need at most size bytes
self.out.write(struct.pack('>cI', channel, size))
self.out.flush()
length = self.in_.read(4)
length = struct.unpack('>I', length)[0]
if not length:
return ''
else:
return self.in_.read(length)
def readline(self, size=-1):
if size < 0:
size = self.maxchunksize
s = self._read(size, 'L')
buf = s
# keep asking for more until there's either no more or
# we got a full line
while s and s[-1] != '\n':
s = self._read(size, 'L')
buf += s
return buf
else:
return self._read(size, 'L')
def __iter__(self):
return self
def next(self):
l = self.readline()
if not l:
raise StopIteration
return l
def __getattr__(self, attr):
if attr in ('isatty', 'fileno'):
raise AttributeError(attr)
return getattr(self.in_, attr)
class server(object):
"""
Listens for commands on fin, runs them and writes the output on a channel
based stream to fout.
"""
def __init__(self, ui, repo, fin, fout):
self.cwd = os.getcwd()
logpath = ui.config("cmdserver", "log", None)
if logpath:
global logfile
if logpath == '-':
# write log on a special 'd' (debug) channel
logfile = channeledoutput(fout, 'd')
else:
logfile = open(logpath, 'a')
if repo:
# the ui here is really the repo ui so take its baseui so we don't
# end up with its local configuration
self.ui = repo.baseui
self.repo = repo
self.repoui = repo.ui
else:
self.ui = ui
self.repo = self.repoui = None
self.cerr = channeledoutput(fout, 'e')
self.cout = channeledoutput(fout, 'o')
self.cin = channeledinput(fin, fout, 'I')
self.cresult = channeledoutput(fout, 'r')
self.client = fin
def _read(self, size):
if not size:
return ''
data = self.client.read(size)
# is the other end closed?
if not data:
raise EOFError
return data
def runcommand(self):
""" reads a list of \0 terminated arguments, executes
and writes the return code to the result channel """
length = struct.unpack('>I', self._read(4))[0]
if not length:
args = []
else:
args = self._read(length).split('\0')
# copy the uis so changes (e.g. --config or --verbose) don't
# persist between requests
copiedui = self.ui.copy()
uis = [copiedui]
if self.repo:
self.repo.baseui = copiedui
# clone ui without using ui.copy because this is protected
repoui = self.repoui.__class__(self.repoui)
repoui.copy = copiedui.copy # redo copy protection
uis.append(repoui)
self.repo.ui = self.repo.dirstate._ui = repoui
self.repo.invalidateall()
for ui in uis:
# any kind of interaction must use server channels
ui.setconfig('ui', 'nontty', 'true', 'commandserver')
req = dispatch.request(args[:], copiedui, self.repo, self.cin,
self.cout, self.cerr)
ret = (dispatch.dispatch(req) or 0) & 255 # might return None
# restore old cwd
if '--cwd' in args:
os.chdir(self.cwd)
self.cresult.write(struct.pack('>i', int(ret)))
def getencoding(self):
""" writes the current encoding to the result channel """
self.cresult.write(encoding.encoding)
def serveone(self):
cmd = self.client.readline()[:-1]
if cmd:
handler = self.capabilities.get(cmd)
if handler:
handler(self)
else:
# clients are expected to check what commands are supported by
# looking at the servers capabilities
raise util.Abort(_('unknown command %s') % cmd)
return cmd != ''
capabilities = {'runcommand' : runcommand,
'getencoding' : getencoding}
def serve(self):
hellomsg = 'capabilities: ' + ' '.join(sorted(self.capabilities))
hellomsg += '\n'
hellomsg += 'encoding: ' + encoding.encoding
hellomsg += '\n'
hellomsg += 'pid: %d' % os.getpid()
# write the hello msg in -one- chunk
self.cout.write(hellomsg)
try:
while self.serveone():
pass
except EOFError:
# we'll get here if the client disconnected while we were reading
# its request
return 1
return 0
class pipeservice(object):
def __init__(self, ui, repo, opts):
self.server = server(ui, repo, sys.stdin, sys.stdout)
def init(self):
pass
def run(self):
return self.server.serve()
class _requesthandler(SocketServer.StreamRequestHandler):
def handle(self):
ui = self.server.ui
repo = self.server.repo
sv = server(ui, repo, self.rfile, self.wfile)
try:
try:
sv.serve()
# handle exceptions that may be raised by command server. most of
# known exceptions are caught by dispatch.
except util.Abort, inst:
ui.warn(_('abort: %s\n') % inst)
except IOError, inst:
if inst.errno != errno.EPIPE:
raise
except KeyboardInterrupt:
pass
except: # re-raises
# also write traceback to error channel. otherwise client cannot
# see it because it is written to server's stderr by default.
traceback.print_exc(file=sv.cerr)
raise
class unixservice(object):
"""
Listens on unix domain socket and forks server per connection
"""
def __init__(self, ui, repo, opts):
self.ui = ui
self.repo = repo
self.address = opts['address']
if not util.safehasattr(SocketServer, 'UnixStreamServer'):
raise util.Abort(_('unsupported platform'))
if not self.address:
raise util.Abort(_('no socket path specified with --address'))
def init(self):
class cls(SocketServer.ForkingMixIn, SocketServer.UnixStreamServer):
ui = self.ui
repo = self.repo
self.server = cls(self.address, _requesthandler)
self.ui.status(_('listening at %s\n') % self.address)
self.ui.flush() # avoid buffering of status message
def run(self):
try:
self.server.serve_forever()
finally:
os.unlink(self.address)
_servicemap = {
'pipe': pipeservice,
'unix': unixservice,
}
def createservice(ui, repo, opts):
mode = opts['cmdserver']
try:
return _servicemap[mode](ui, repo, opts)
except KeyError:
raise util.Abort(_('unknown mode %s') % mode)