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localrepo: iteratively derive local repository type...
localrepo: iteratively derive local repository type This commit implements the dynamic local repository type derivation that was explained in the recent commit bfeab472e3c0 "localrepo: create new function for instantiating a local repo object." Instead of a static localrepository class/type which must be customized after construction, we now dynamically construct a type by building up base classes/types to represent specific repository interfaces. Conceptually, the end state is similar to what was happening when various extensions would monkeypatch the __class__ of newly-constructed repo instances. However, the approach is inverted. Instead of making the instance then customizing it, we do the customization up front by influencing the behavior of the type then we instantiate that custom type. This approach gives us much more flexibility. For example, we can use completely separate classes for implementing different aspects of the repository. For example, we could have one class representing revlog-based file storage and another representing non-revlog based file storage. When then choose which implementation to use based on the presence of repo requirements. A concern with this approach is that it creates a lot more types and complexity and that complexity adds overhead. Yes, it is true that this approach will result in more types being created. Yes, this is more complicated than traditional "instantiate a static type." However, I believe the alternatives to supporting alternate storage backends are just as complicated. (Before I arrived at this solution, I had patches storing factory functions on local repo instances for e.g. constructing a file storage instance. We ended up having a handful of these. And this was logically identical to assigning custom methods. Since we were logically changing the type of the instance, I figured it would be better to just use specialized types instead of introducing levels of abstraction at run-time.) On the performance front, I don't believe that having N base classes has any significant performance overhead compared to just a single base class. Intuition says that Python will need to iterate the base classes to find an attribute. However, CPython caches method lookups: as long as the __class__ or MRO isn't changing, method attribute lookup should be constant time after first access. And non-method attributes are stored in __dict__, of which there is only 1 per object, so the number of base classes for __dict__ is irrelevant. Anyway, this commit splits up the monolithic completelocalrepository interface into sub-interfaces: 1 for file storage and 1 representing everything else. We've taught ``makelocalrepository()`` to call a series of factory functions which will produce types implementing specific interfaces. It then calls type() to create a new type from the built-up list of base types. This commit should be considered a start and not the end state. I suspect we'll hit a number of problems as we start to implement alternate storage backends: * Passing custom arguments to __init__ and setting custom attributes on __dict__. * Customizing the set of interfaces that are needed. e.g. the "readonly" intent could translate to not requesting an interface providing methods related to writing. * More ergonomic way for extensions to insert themselves so their callbacks aren't unconditionally called. * Wanting to modify vfs instances, other arguments passed to __init__. That being said, this code is usable in its current state and I'm convinced future commits will demonstrate the value in this approach. Differential Revision: https://phab.mercurial-scm.org/D4642

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server.py
210 lines | 6.8 KiB | text/x-python | PythonLexer
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 # 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
from .i18n import _
from . import (
Yuya Nishihara
chgserver: make it a core module and drop extension flags...
r30513 chgserver,
Matt Harbison
serve: add support for Mercurial subrepositories...
r32005 cmdutil,
Yuya Nishihara
server: move service table and factory from commandserver...
r30507 commandserver,
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 error,
Yuya Nishihara
server: move service factory from hgweb
r30509 hgweb,
Augie Fackler
server: use pycompat to get argv
r32530 pycompat,
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 util,
)
Yuya Nishihara
procutil: bulk-replace util.std* to point to new module
r37137 from .utils import (
procutil,
)
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 def runservice(opts, parentfn=None, initfn=None, runfn=None, logfile=None,
runargs=None, appendpid=False):
'''Run a command as a service.'''
Matt Harbison
server: refactor 'daemon_postexec' instructions into a dictionary
r37232 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)
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229 # 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']:
Matt Harbison
server: refactor 'daemon_postexec' instructions into a dictionary
r37232 if 'unlink' in postexecargs and os.path.exists(postexecargs['unlink']):
procutil.stdout.flush()
procutil.stderr.flush()
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229
Matt Harbison
server: refactor 'daemon_postexec' instructions into a dictionary
r37232 fd = os.open(postexecargs['unlink'],
os.O_WRONLY | os.O_APPEND | os.O_BINARY)
try:
Matt Harbison
server: minor code cleanup...
r37233 os.dup2(fd, procutil.stdout.fileno())
os.dup2(fd, procutil.stderr.fileno())
Matt Harbison
server: refactor 'daemon_postexec' instructions into a dictionary
r37232 finally:
os.close(fd)
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 def writepid(pid):
if opts['pid_file']:
if appendpid:
Augie Fackler
server: write out pid using bytes IO instead of str IO
r32548 mode = 'ab'
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 else:
Augie Fackler
server: write out pid using bytes IO instead of str IO
r32548 mode = 'wb'
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 fp = open(opts['pid_file'], mode)
Yuya Nishihara
py3: simply use b'%d\n' to format pid in server.py...
r32617 fp.write('%d\n' % pid)
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 fp.close()
if opts['daemon'] and not opts['daemon_postexec']:
# Signal child process startup with file removal
Yuya Nishihara
py3: wrap tempfile.mkstemp() to use bytes path...
r38182 lockfd, lockpath = pycompat.mkstemp(prefix='hg-service-')
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 os.close(lockfd)
try:
if not runargs:
Yuya Nishihara
procutil: bulk-replace function calls to point to new module
r37138 runargs = procutil.hgcmd() + pycompat.sysargv[1:]
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 runargs.append('--daemon-postexec=unlink:%s' % lockpath)
# Don't pass --cwd to the child process, because we've already
# changed directory.
Gregory Szorc
global: use pycompat.xrange()...
r38806 for i in pycompat.xrange(1, len(runargs)):
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 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)
Yuya Nishihara
procutil: bulk-replace function calls to point to new module
r37138 pid = procutil.rundetached(runargs, condfn)
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 if pid < 0:
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229 # If the daemonized process managed to write out an error msg,
# report it.
if pycompat.iswindows and os.path.exists(lockpath):
Matt Harbison
server: minor code cleanup...
r37233 with open(lockpath, 'rb') as log:
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229 for line in log:
procutil.stderr.write(line)
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 raise error.Abort(_('child process failed to start'))
writepid(pid)
finally:
Ryan McElroy
server: use tryunlink
r31548 util.tryunlink(lockpath)
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 if parentfn:
return parentfn(pid)
else:
return
if initfn:
initfn()
if not opts['daemon']:
Yuya Nishihara
procutil: bulk-replace function calls to point to new module
r37138 writepid(procutil.getpid())
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506
if opts['daemon_postexec']:
try:
os.setsid()
except AttributeError:
pass
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229
Matt Harbison
server: refactor 'daemon_postexec' instructions into a dictionary
r37232 if 'chdir' in postexecargs:
os.chdir(postexecargs['chdir'])
Yuya Nishihara
procutil: bulk-replace function calls to point to new module
r37138 procutil.hidewindow()
Yuya Nishihara
procutil: bulk-replace util.std* to point to new module
r37137 procutil.stdout.flush()
procutil.stderr.flush()
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506
nullfd = os.open(os.devnull, os.O_RDWR)
logfilefd = nullfd
if logfile:
Yuya Nishihara
server: drop executable bit from daemon log file...
r34925 logfilefd = os.open(logfile, os.O_RDWR | os.O_CREAT | os.O_APPEND,
0o666)
Matt Harbison
server: minor code cleanup...
r37233 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:
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 os.close(nullfd)
Matt Harbison
server: minor code cleanup...
r37233 if logfile and logfilefd not in stdio:
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 os.close(logfilefd)
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229 # Only unlink after redirecting stdout/stderr, so Windows doesn't
# complain about a sharing violation.
Matt Harbison
server: refactor 'daemon_postexec' instructions into a dictionary
r37232 if 'unlink' in postexecargs:
os.unlink(postexecargs['unlink'])
Matt Harbison
server: add an error feedback mechanism for when the daemon fails to launch...
r37229
Yuya Nishihara
server: move cmdutil.service() to new module (API)...
r30506 if runfn:
return runfn()
Yuya Nishihara
server: move service table and factory from commandserver...
r30507
_cmdservicemap = {
Yuya Nishihara
chgserver: make it a core module and drop extension flags...
r30513 'chgunix': chgserver.chgunixservice,
Yuya Nishihara
server: move service table and factory from commandserver...
r30507 'pipe': commandserver.pipeservice,
'unix': commandserver.unixforkingservice,
}
Yuya Nishihara
server: add public function to select either cmdserver or hgweb
r30510 def _createcmdservice(ui, repo, opts):
Yuya Nishihara
server: move service table and factory from commandserver...
r30507 mode = opts['cmdserver']
try:
return _cmdservicemap[mode](ui, repo, opts)
except KeyError:
raise error.Abort(_('unknown mode %s') % mode)
Yuya Nishihara
server: move service factory from hgweb
r30509
Yuya Nishihara
server: add public function to select either cmdserver or hgweb
r30510 def _createhgwebservice(ui, repo, opts):
Yuya Nishihara
server: move service factory from hgweb
r30509 # this way we can check if something was given in the command-line
if opts.get('port'):
opts['port'] = util.getport(opts.get('port'))
Martin von Zweigbergk
cleanup: use set literals...
r32291 alluis = {ui}
Yuya Nishihara
server: move service factory from hgweb
r30509 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:
Matt Harbison
serve: add support for Mercurial subrepositories...
r32005 if opts.get('subrepos'):
raise error.Abort(_('--web-conf cannot be used with --subrepos'))
Yuya Nishihara
server: move service factory from hgweb
r30509 # 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)
Matt Harbison
serve: add support for Mercurial subrepositories...
r32005 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)
Yuya Nishihara
server: move service factory from hgweb
r30509 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)
Yuya Nishihara
server: add public function to select either cmdserver or hgweb
r30510
def createservice(ui, repo, opts):
if opts["cmdserver"]:
return _createcmdservice(ui, repo, opts)
else:
return _createhgwebservice(ui, repo, opts)