##// END OF EJS Templates
server: add an error feedback mechanism for when the daemon fails to launch...
server: add an error feedback mechanism for when the daemon fails to launch There's a recurring problem on Windows where `hg serve -d` will randomly fail to spawn a detached process. The reason for the failure is completely hidden, and it takes hours to get a single failure on my laptop. All this does is redirect stdout/stderr of the child to a file until the lock file is freed, and then the parent dumps it out if it fails to spawn. I chose to put the output into the lock file because that is always cleaned up. There's no way to report errors after that anyway. On Windows, killdaemons.py is roughly `kill -9`, so this ensures that junk won't pile up. This may end up being a case of EADDRINUSE. At least that's what I saw spit out a few times (among other odd errors and missing output on Windows). But I also managed to get the same thing on Fedora 26 by running test-hgwebdir.t with --loop -j10 for several hours. Running `netstat` immediately after killing that run printed a wall of sockets in the TIME_WAIT state, which were gone a couple seconds later. I couldn't match up ports that failed, because --loop doesn't print out the message about the port that was used. So maybe the fix is to rotate the use of HGPORT[12] in the tests. But, let's collect some more data first.

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server.py
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# server.py - utility and factory of server
#
# 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 os
import tempfile
from .i18n import _
from . import (
chgserver,
cmdutil,
commandserver,
error,
hgweb,
pycompat,
util,
)
from .utils import (
procutil,
)
def runservice(opts, parentfn=None, initfn=None, runfn=None, logfile=None,
runargs=None, appendpid=False):
'''Run a command as a service.'''
# When daemonized on Windows, redirect stdout/stderr to the lockfile (which
# gets cleaned up after the child is up and running), so that the parent can
# read and print the error if this child dies early. See 594dd384803c. On
# other platforms, the child can write to the parent's stdio directly, until
# it is redirected prior to runfn().
if pycompat.iswindows and opts['daemon_postexec']:
for inst in opts['daemon_postexec']:
if inst.startswith('unlink:'):
lockpath = inst[7:]
if os.path.exists(lockpath):
procutil.stdout.flush()
procutil.stderr.flush()
fd = os.open(lockpath,
os.O_WRONLY | os.O_APPEND | os.O_BINARY)
try:
os.dup2(fd, 1)
os.dup2(fd, 2)
finally:
os.close(fd)
def writepid(pid):
if opts['pid_file']:
if appendpid:
mode = 'ab'
else:
mode = 'wb'
fp = open(opts['pid_file'], mode)
fp.write('%d\n' % pid)
fp.close()
if opts['daemon'] and not opts['daemon_postexec']:
# Signal child process startup with file removal
lockfd, lockpath = tempfile.mkstemp(prefix='hg-service-')
os.close(lockfd)
try:
if not runargs:
runargs = procutil.hgcmd() + pycompat.sysargv[1:]
runargs.append('--daemon-postexec=unlink:%s' % lockpath)
# Don't pass --cwd to the child process, because we've already
# changed directory.
for i in xrange(1, len(runargs)):
if runargs[i].startswith('--cwd='):
del runargs[i]
break
elif runargs[i].startswith('--cwd'):
del runargs[i:i + 2]
break
def condfn():
return not os.path.exists(lockpath)
pid = procutil.rundetached(runargs, condfn)
if pid < 0:
# If the daemonized process managed to write out an error msg,
# report it.
if pycompat.iswindows and os.path.exists(lockpath):
with open(lockpath) as log:
for line in log:
procutil.stderr.write(line)
raise error.Abort(_('child process failed to start'))
writepid(pid)
finally:
util.tryunlink(lockpath)
if parentfn:
return parentfn(pid)
else:
return
if initfn:
initfn()
if not opts['daemon']:
writepid(procutil.getpid())
if opts['daemon_postexec']:
try:
os.setsid()
except AttributeError:
pass
lockpath = None
for inst in opts['daemon_postexec']:
if inst.startswith('unlink:'):
lockpath = inst[7:]
elif inst.startswith('chdir:'):
os.chdir(inst[6:])
elif inst != 'none':
raise error.Abort(_('invalid value for --daemon-postexec: %s')
% inst)
procutil.hidewindow()
procutil.stdout.flush()
procutil.stderr.flush()
nullfd = os.open(os.devnull, os.O_RDWR)
logfilefd = nullfd
if logfile:
logfilefd = os.open(logfile, os.O_RDWR | os.O_CREAT | os.O_APPEND,
0o666)
os.dup2(nullfd, 0)
os.dup2(logfilefd, 1)
os.dup2(logfilefd, 2)
if nullfd not in (0, 1, 2):
os.close(nullfd)
if logfile and logfilefd not in (0, 1, 2):
os.close(logfilefd)
# Only unlink after redirecting stdout/stderr, so Windows doesn't
# complain about a sharing violation.
if lockpath:
os.unlink(lockpath)
if runfn:
return runfn()
_cmdservicemap = {
'chgunix': chgserver.chgunixservice,
'pipe': commandserver.pipeservice,
'unix': commandserver.unixforkingservice,
}
def _createcmdservice(ui, repo, opts):
mode = opts['cmdserver']
try:
return _cmdservicemap[mode](ui, repo, opts)
except KeyError:
raise error.Abort(_('unknown mode %s') % mode)
def _createhgwebservice(ui, repo, opts):
# this way we can check if something was given in the command-line
if opts.get('port'):
opts['port'] = util.getport(opts.get('port'))
alluis = {ui}
if repo:
baseui = repo.baseui
alluis.update([repo.baseui, repo.ui])
else:
baseui = ui
webconf = opts.get('web_conf') or opts.get('webdir_conf')
if webconf:
if opts.get('subrepos'):
raise error.Abort(_('--web-conf cannot be used with --subrepos'))
# load server settings (e.g. web.port) to "copied" ui, which allows
# hgwebdir to reload webconf cleanly
servui = ui.copy()
servui.readconfig(webconf, sections=['web'])
alluis.add(servui)
elif opts.get('subrepos'):
servui = ui
# If repo is None, hgweb.createapp() already raises a proper abort
# message as long as webconf is None.
if repo:
webconf = dict()
cmdutil.addwebdirpath(repo, "", webconf)
else:
servui = ui
optlist = ("name templates style address port prefix ipv6"
" accesslog errorlog certificate encoding")
for o in optlist.split():
val = opts.get(o, '')
if val in (None, ''): # should check against default options instead
continue
for u in alluis:
u.setconfig("web", o, val, 'serve')
app = hgweb.createapp(baseui, repo, webconf)
return hgweb.httpservice(servui, app, opts)
def createservice(ui, repo, opts):
if opts["cmdserver"]:
return _createcmdservice(ui, repo, opts)
else:
return _createhgwebservice(ui, repo, opts)