view mercurial/server.py @ 37485:0b7475ea38cf

wireproto: port heads command to wire protocol v2

After much thought and consideration, wire protocol version 2's
commands will be defined in different functions from the existing
commands. This will make it easier to implement these commands
because it won't require shoehorning things like response formatting
and argument declaration into the same APIs.

For example, wire protocol version 1 requires that commands declare
a fixed and ordered list of argument names. It isn't really possible
to insert new arguments or have optional arguments without
breaking backwards compatibility. Wire protocol version 2, however,
uses CBOR maps for passing arguments. So arguments a) can be
optional b) can be added without BC c) can be strongly typed.

This commit starts our trek towards reimplementing the wire protocol
for version 2 with the heads command. It is pretty similar to the
existing heads command. One added feature is it can be told to
operate on only public phase changesets. This is useful for
making discovery faster when a repo has tens of thousands of
draft phase heads (such as Mozilla's "try" repository).

The HTTPv2 server-side protocol has had its `getargs()` implementation
updated to reflect that arguments are a map and not a list.

Differential Revision: https://phab.mercurial-scm.org/D3179

# server.py - utility and factory of server
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# 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.'''

    postexecargs = {}

    if opts['daemon_postexec']:
        for inst in opts['daemon_postexec']:
            if inst.startswith('unlink:'):
                postexecargs['unlink'] = inst[7:]
            elif inst.startswith('chdir:'):
                postexecargs['chdir'] = inst[6:]
            elif inst != 'none':
                raise error.Abort(_('invalid value for --daemon-postexec: %s')
                                  % inst)

    # 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']:
        if 'unlink' in postexecargs and os.path.exists(postexecargs['unlink']):
            procutil.stdout.flush()
            procutil.stderr.flush()

            fd = os.open(postexecargs['unlink'],
                         os.O_WRONLY | os.O_APPEND | os.O_BINARY)
            try:
                os.dup2(fd, procutil.stdout.fileno())
                os.dup2(fd, procutil.stderr.fileno())
            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, 'rb') 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

        if 'chdir' in postexecargs:
            os.chdir(postexecargs['chdir'])
        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, procutil.stdin.fileno())
        os.dup2(logfilefd, procutil.stdout.fileno())
        os.dup2(logfilefd, procutil.stderr.fileno())
        stdio = (procutil.stdin.fileno(), procutil.stdout.fileno(),
                 procutil.stderr.fileno())
        if nullfd not in stdio:
            os.close(nullfd)
        if logfile and logfilefd not in stdio:
            os.close(logfilefd)

        # Only unlink after redirecting stdout/stderr, so Windows doesn't
        # complain about a sharing violation.
        if 'unlink' in postexecargs:
            os.unlink(postexecargs['unlink'])

    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)