cmdserver: write early exception to 'e' channel in 'unix' mode
In 'unix' mode, the server is typically detached from the console. Therefore
a client couldn't see the exception that occurred while instantiating the
server object.
This patch tries to catch the early error and send it to 'e' channel even if
the server isn't instantiated yet. This means the error may be sent before the
initial hello message. So it's up to the client implementation whether to
handle the early error message or error out as protocol violation.
The error handling code is also copied to chgserver.py. I'll factor out them
later if we manage to get chg passes the test suite.
# chgserver.py - command server extension for cHg
#
# Copyright 2011 Yuya Nishihara <yuya@tcha.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""command server extension for cHg (EXPERIMENTAL)
'S' channel (read/write)
propagate ui.system() request to client
'attachio' command
attach client's stdio passed by sendmsg()
'chdir' command
change current directory
'getpager' command
checks if pager is enabled and which pager should be executed
'setenv' command
replace os.environ completely
'setumask' command
set umask
'validate' command
reload the config and check if the server is up to date
Config
------
::
[chgserver]
idletimeout = 3600 # seconds, after which an idle server will exit
skiphash = False # whether to skip config or env change checks
"""
from __future__ import absolute_import
import SocketServer
import errno
import inspect
import os
import re
import struct
import sys
import threading
import time
import traceback
from mercurial.i18n import _
from mercurial import (
cmdutil,
commands,
commandserver,
dispatch,
error,
extensions,
osutil,
util,
)
# Note for extension authors: ONLY specify testedwith = 'internal' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'internal'
_log = commandserver.log
def _hashlist(items):
"""return sha1 hexdigest for a list"""
return util.sha1(str(items)).hexdigest()
# sensitive config sections affecting confighash
_configsections = [
'extdiff', # uisetup will register new commands
'extensions',
]
# sensitive environment variables affecting confighash
_envre = re.compile(r'''\A(?:
CHGHG
|HG.*
|LANG(?:UAGE)?
|LC_.*
|LD_.*
|PATH
|PYTHON.*
|TERM(?:INFO)?
|TZ
)\Z''', re.X)
def _confighash(ui):
"""return a quick hash for detecting config/env changes
confighash is the hash of sensitive config items and environment variables.
for chgserver, it is designed that once confighash changes, the server is
not qualified to serve its client and should redirect the client to a new
server. different from mtimehash, confighash change will not mark the
server outdated and exit since the user can have different configs at the
same time.
"""
sectionitems = []
for section in _configsections:
sectionitems.append(ui.configitems(section))
sectionhash = _hashlist(sectionitems)
envitems = [(k, v) for k, v in os.environ.iteritems() if _envre.match(k)]
envhash = _hashlist(sorted(envitems))
return sectionhash[:6] + envhash[:6]
def _getmtimepaths(ui):
"""get a list of paths that should be checked to detect change
The list will include:
- extensions (will not cover all files for complex extensions)
- mercurial/__version__.py
- python binary
"""
modules = [m for n, m in extensions.extensions(ui)]
try:
from mercurial import __version__
modules.append(__version__)
except ImportError:
pass
files = [sys.executable]
for m in modules:
try:
files.append(inspect.getabsfile(m))
except TypeError:
pass
return sorted(set(files))
def _mtimehash(paths):
"""return a quick hash for detecting file changes
mtimehash calls stat on given paths and calculate a hash based on size and
mtime of each file. mtimehash does not read file content because reading is
expensive. therefore it's not 100% reliable for detecting content changes.
it's possible to return different hashes for same file contents.
it's also possible to return a same hash for different file contents for
some carefully crafted situation.
for chgserver, it is designed that once mtimehash changes, the server is
considered outdated immediately and should no longer provide service.
"""
def trystat(path):
try:
st = os.stat(path)
return (st.st_mtime, st.st_size)
except OSError:
# could be ENOENT, EPERM etc. not fatal in any case
pass
return _hashlist(map(trystat, paths))[:12]
class hashstate(object):
"""a structure storing confighash, mtimehash, paths used for mtimehash"""
def __init__(self, confighash, mtimehash, mtimepaths):
self.confighash = confighash
self.mtimehash = mtimehash
self.mtimepaths = mtimepaths
@staticmethod
def fromui(ui, mtimepaths=None):
if mtimepaths is None:
mtimepaths = _getmtimepaths(ui)
confighash = _confighash(ui)
mtimehash = _mtimehash(mtimepaths)
_log('confighash = %s mtimehash = %s\n' % (confighash, mtimehash))
return hashstate(confighash, mtimehash, mtimepaths)
# copied from hgext/pager.py:uisetup()
def _setuppagercmd(ui, options, cmd):
if not ui.formatted():
return
p = ui.config("pager", "pager", os.environ.get("PAGER"))
usepager = False
always = util.parsebool(options['pager'])
auto = options['pager'] == 'auto'
if not p:
pass
elif always:
usepager = True
elif not auto:
usepager = False
else:
attended = ['annotate', 'cat', 'diff', 'export', 'glog', 'log', 'qdiff']
attend = ui.configlist('pager', 'attend', attended)
ignore = ui.configlist('pager', 'ignore')
cmds, _ = cmdutil.findcmd(cmd, commands.table)
for cmd in cmds:
var = 'attend-%s' % cmd
if ui.config('pager', var):
usepager = ui.configbool('pager', var)
break
if (cmd in attend or
(cmd not in ignore and not attend)):
usepager = True
break
if usepager:
ui.setconfig('ui', 'formatted', ui.formatted(), 'pager')
ui.setconfig('ui', 'interactive', False, 'pager')
return p
_envvarre = re.compile(r'\$[a-zA-Z_]+')
def _clearenvaliases(cmdtable):
"""Remove stale command aliases referencing env vars; variable expansion
is done at dispatch.addaliases()"""
for name, tab in cmdtable.items():
cmddef = tab[0]
if (isinstance(cmddef, dispatch.cmdalias) and
not cmddef.definition.startswith('!') and # shell alias
_envvarre.search(cmddef.definition)):
del cmdtable[name]
def _newchgui(srcui, csystem):
class chgui(srcui.__class__):
def __init__(self, src=None):
super(chgui, self).__init__(src)
if src:
self._csystem = getattr(src, '_csystem', csystem)
else:
self._csystem = csystem
def system(self, cmd, environ=None, cwd=None, onerr=None,
errprefix=None):
# copied from mercurial/util.py:system()
self.flush()
def py2shell(val):
if val is None or val is False:
return '0'
if val is True:
return '1'
return str(val)
env = os.environ.copy()
if environ:
env.update((k, py2shell(v)) for k, v in environ.iteritems())
env['HG'] = util.hgexecutable()
rc = self._csystem(cmd, env, cwd)
if rc and onerr:
errmsg = '%s %s' % (os.path.basename(cmd.split(None, 1)[0]),
util.explainexit(rc)[0])
if errprefix:
errmsg = '%s: %s' % (errprefix, errmsg)
raise onerr(errmsg)
return rc
return chgui(srcui)
def _renewui(srcui, args=None):
if not args:
args = []
newui = srcui.__class__()
for a in ['fin', 'fout', 'ferr', 'environ']:
setattr(newui, a, getattr(srcui, a))
if util.safehasattr(srcui, '_csystem'):
newui._csystem = srcui._csystem
# load wd and repo config, copied from dispatch.py
cwds = dispatch._earlygetopt(['--cwd'], args)
cwd = cwds and os.path.realpath(cwds[-1]) or None
rpath = dispatch._earlygetopt(["-R", "--repository", "--repo"], args)
path, newui = dispatch._getlocal(newui, rpath, wd=cwd)
# internal config: extensions.chgserver
# copy it. it can only be overrided from command line.
newui.setconfig('extensions', 'chgserver',
srcui.config('extensions', 'chgserver'), '--config')
# command line args
dispatch._parseconfig(newui, dispatch._earlygetopt(['--config'], args))
# stolen from tortoisehg.util.copydynamicconfig()
for section, name, value in srcui.walkconfig():
source = srcui.configsource(section, name)
if ':' in source or source == '--config':
# path:line or command line
continue
if source == 'none':
# ui.configsource returns 'none' by default
source = ''
newui.setconfig(section, name, value, source)
return newui
class channeledsystem(object):
"""Propagate ui.system() request in the following format:
payload length (unsigned int),
cmd, '\0',
cwd, '\0',
envkey, '=', val, '\0',
...
envkey, '=', val
and waits:
exitcode length (unsigned int),
exitcode (int)
"""
def __init__(self, in_, out, channel):
self.in_ = in_
self.out = out
self.channel = channel
def __call__(self, cmd, environ, cwd):
args = [util.quotecommand(cmd), cwd or '.']
args.extend('%s=%s' % (k, v) for k, v in environ.iteritems())
data = '\0'.join(args)
self.out.write(struct.pack('>cI', self.channel, len(data)))
self.out.write(data)
self.out.flush()
length = self.in_.read(4)
length, = struct.unpack('>I', length)
if length != 4:
raise error.Abort(_('invalid response'))
rc, = struct.unpack('>i', self.in_.read(4))
return rc
_iochannels = [
# server.ch, ui.fp, mode
('cin', 'fin', 'rb'),
('cout', 'fout', 'wb'),
('cerr', 'ferr', 'wb'),
]
class chgcmdserver(commandserver.server):
def __init__(self, ui, repo, fin, fout, sock, hashstate, baseaddress):
super(chgcmdserver, self).__init__(
_newchgui(ui, channeledsystem(fin, fout, 'S')), repo, fin, fout)
self.clientsock = sock
self._oldios = [] # original (self.ch, ui.fp, fd) before "attachio"
self.hashstate = hashstate
self.baseaddress = baseaddress
if hashstate is not None:
self.capabilities = self.capabilities.copy()
self.capabilities['validate'] = chgcmdserver.validate
def cleanup(self):
# dispatch._runcatch() does not flush outputs if exception is not
# handled by dispatch._dispatch()
self.ui.flush()
self._restoreio()
def attachio(self):
"""Attach to client's stdio passed via unix domain socket; all
channels except cresult will no longer be used
"""
# tell client to sendmsg() with 1-byte payload, which makes it
# distinctive from "attachio\n" command consumed by client.read()
self.clientsock.sendall(struct.pack('>cI', 'I', 1))
clientfds = osutil.recvfds(self.clientsock.fileno())
_log('received fds: %r\n' % clientfds)
ui = self.ui
ui.flush()
first = self._saveio()
for fd, (cn, fn, mode) in zip(clientfds, _iochannels):
assert fd > 0
fp = getattr(ui, fn)
os.dup2(fd, fp.fileno())
os.close(fd)
if not first:
continue
# reset buffering mode when client is first attached. as we want
# to see output immediately on pager, the mode stays unchanged
# when client re-attached. ferr is unchanged because it should
# be unbuffered no matter if it is a tty or not.
if fn == 'ferr':
newfp = fp
else:
# make it line buffered explicitly because the default is
# decided on first write(), where fout could be a pager.
if fp.isatty():
bufsize = 1 # line buffered
else:
bufsize = -1 # system default
newfp = os.fdopen(fp.fileno(), mode, bufsize)
setattr(ui, fn, newfp)
setattr(self, cn, newfp)
self.cresult.write(struct.pack('>i', len(clientfds)))
def _saveio(self):
if self._oldios:
return False
ui = self.ui
for cn, fn, _mode in _iochannels:
ch = getattr(self, cn)
fp = getattr(ui, fn)
fd = os.dup(fp.fileno())
self._oldios.append((ch, fp, fd))
return True
def _restoreio(self):
ui = self.ui
for (ch, fp, fd), (cn, fn, _mode) in zip(self._oldios, _iochannels):
newfp = getattr(ui, fn)
# close newfp while it's associated with client; otherwise it
# would be closed when newfp is deleted
if newfp is not fp:
newfp.close()
# restore original fd: fp is open again
os.dup2(fd, fp.fileno())
os.close(fd)
setattr(self, cn, ch)
setattr(ui, fn, fp)
del self._oldios[:]
def validate(self):
"""Reload the config and check if the server is up to date
Read a list of '\0' separated arguments.
Write a non-empty list of '\0' separated instruction strings or '\0'
if the list is empty.
An instruction string could be either:
- "unlink $path", the client should unlink the path to stop the
outdated server.
- "redirect $path", the client should try to connect to another
server instead.
"""
args = self._readlist()
self.ui = _renewui(self.ui, args)
newhash = hashstate.fromui(self.ui, self.hashstate.mtimepaths)
insts = []
if newhash.mtimehash != self.hashstate.mtimehash:
addr = _hashaddress(self.baseaddress, self.hashstate.confighash)
insts.append('unlink %s' % addr)
if newhash.confighash != self.hashstate.confighash:
addr = _hashaddress(self.baseaddress, newhash.confighash)
insts.append('redirect %s' % addr)
_log('validate: %s\n' % insts)
self.cresult.write('\0'.join(insts) or '\0')
def chdir(self):
"""Change current directory
Note that the behavior of --cwd option is bit different from this.
It does not affect --config parameter.
"""
path = self._readstr()
if not path:
return
_log('chdir to %r\n' % path)
os.chdir(path)
def setumask(self):
"""Change umask"""
mask = struct.unpack('>I', self._read(4))[0]
_log('setumask %r\n' % mask)
os.umask(mask)
def getpager(self):
"""Read cmdargs and write pager command to r-channel if enabled
If pager isn't enabled, this writes '\0' because channeledoutput
does not allow to write empty data.
"""
args = self._readlist()
try:
cmd, _func, args, options, _cmdoptions = dispatch._parse(self.ui,
args)
except (error.Abort, error.AmbiguousCommand, error.CommandError,
error.UnknownCommand):
cmd = None
options = {}
if not cmd or 'pager' not in options:
self.cresult.write('\0')
return
pagercmd = _setuppagercmd(self.ui, options, cmd)
if pagercmd:
self.cresult.write(pagercmd)
else:
self.cresult.write('\0')
def setenv(self):
"""Clear and update os.environ
Note that not all variables can make an effect on the running process.
"""
l = self._readlist()
try:
newenv = dict(s.split('=', 1) for s in l)
except ValueError:
raise ValueError('unexpected value in setenv request')
diffkeys = set(k for k in set(os.environ.keys() + newenv.keys())
if os.environ.get(k) != newenv.get(k))
_log('change env: %r\n' % sorted(diffkeys))
os.environ.clear()
os.environ.update(newenv)
if set(['HGPLAIN', 'HGPLAINEXCEPT']) & diffkeys:
# reload config so that ui.plain() takes effect
self.ui = _renewui(self.ui)
_clearenvaliases(commands.table)
capabilities = commandserver.server.capabilities.copy()
capabilities.update({'attachio': attachio,
'chdir': chdir,
'getpager': getpager,
'setenv': setenv,
'setumask': setumask})
# copied from mercurial/commandserver.py
class _requesthandler(SocketServer.StreamRequestHandler):
def handle(self):
# use a different process group from the master process, making this
# process pass kernel "is_current_pgrp_orphaned" check so signals like
# SIGTSTP, SIGTTIN, SIGTTOU are not ignored.
os.setpgid(0, 0)
ui = self.server.ui
repo = self.server.repo
sv = None
try:
sv = chgcmdserver(ui, repo, self.rfile, self.wfile, self.connection,
self.server.hashstate, self.server.baseaddress)
try:
sv.serve()
# handle exceptions that may be raised by command server. most of
# known exceptions are caught by dispatch.
except error.Abort as inst:
ui.warn(_('abort: %s\n') % inst)
except IOError as inst:
if inst.errno != errno.EPIPE:
raise
except KeyboardInterrupt:
pass
finally:
sv.cleanup()
except: # re-raises
# also write traceback to error channel. otherwise client cannot
# see it because it is written to server's stderr by default.
if sv:
cerr = sv.cerr
else:
cerr = commandserver.channeledoutput(self.wfile, 'e')
traceback.print_exc(file=cerr)
raise
def _tempaddress(address):
return '%s.%d.tmp' % (address, os.getpid())
def _hashaddress(address, hashstr):
return '%s-%s' % (address, hashstr)
class AutoExitMixIn: # use old-style to comply with SocketServer design
lastactive = time.time()
idletimeout = 3600 # default 1 hour
def startautoexitthread(self):
# note: the auto-exit check here is cheap enough to not use a thread,
# be done in serve_forever. however SocketServer is hook-unfriendly,
# you simply cannot hook serve_forever without copying a lot of code.
# besides, serve_forever's docstring suggests using thread.
thread = threading.Thread(target=self._autoexitloop)
thread.daemon = True
thread.start()
def _autoexitloop(self, interval=1):
while True:
time.sleep(interval)
if not self.issocketowner():
_log('%s is not owned, exiting.\n' % self.server_address)
break
if time.time() - self.lastactive > self.idletimeout:
_log('being idle too long. exiting.\n')
break
self.shutdown()
def process_request(self, request, address):
self.lastactive = time.time()
return SocketServer.ForkingMixIn.process_request(
self, request, address)
def server_bind(self):
# use a unique temp address so we can stat the file and do ownership
# check later
tempaddress = _tempaddress(self.server_address)
self.socket.bind(tempaddress)
self._socketstat = os.stat(tempaddress)
# rename will replace the old socket file if exists atomically. the
# old server will detect ownership change and exit.
util.rename(tempaddress, self.server_address)
def issocketowner(self):
try:
stat = os.stat(self.server_address)
return (stat.st_ino == self._socketstat.st_ino and
stat.st_mtime == self._socketstat.st_mtime)
except OSError:
return False
def unlinksocketfile(self):
if not self.issocketowner():
return
# it is possible to have a race condition here that we may
# remove another server's socket file. but that's okay
# since that server will detect and exit automatically and
# the client will start a new server on demand.
try:
os.unlink(self.server_address)
except OSError as exc:
if exc.errno != errno.ENOENT:
raise
class chgunixservice(commandserver.unixservice):
def init(self):
self._inithashstate()
class cls(AutoExitMixIn, SocketServer.ForkingMixIn,
SocketServer.UnixStreamServer):
ui = self.ui
repo = self.repo
hashstate = self.hashstate
baseaddress = self.baseaddress
self.server = cls(self.address, _requesthandler)
self.server.idletimeout = self.ui.configint(
'chgserver', 'idletimeout', self.server.idletimeout)
self.server.startautoexitthread()
self._createsymlink()
def _inithashstate(self):
self.baseaddress = self.address
if self.ui.configbool('chgserver', 'skiphash', False):
self.hashstate = None
return
self.hashstate = hashstate.fromui(self.ui)
self.address = _hashaddress(self.address, self.hashstate.confighash)
def _createsymlink(self):
if self.baseaddress == self.address:
return
tempaddress = _tempaddress(self.baseaddress)
os.symlink(os.path.basename(self.address), tempaddress)
util.rename(tempaddress, self.baseaddress)
def run(self):
try:
self.server.serve_forever()
finally:
self.server.unlinksocketfile()
def uisetup(ui):
commandserver._servicemap['chgunix'] = chgunixservice
# CHGINTERNALMARK is temporarily set by chg client to detect if chg will
# start another chg. drop it to avoid possible side effects.
if 'CHGINTERNALMARK' in os.environ:
del os.environ['CHGINTERNALMARK']