Mercurial > hg
view contrib/hgclient.py @ 29544:024e8f82f3de
commandserver: add new forking server implemented without using SocketServer
SocketServer.ForkingMixIn of Python 2.x has a couple of issues, such as:
- race condition that leads to 100% CPU usage (Python 2.6)
https://bugs.python.org/issue21491
- can't wait for children belonging to different process groups (Python 2.6)
- leaves at least one zombie process (Python 2.6, 2.7)
https://bugs.python.org/issue11109
The first two are critical because we do setpgid(0, 0) in child process to
isolate terminal signals. The last one isn't, but ForkingMixIn seems to be
doing silly. So there are two choices:
a) backport and maintain SocketServer until we can drop support for Python 2.x
b) replace SocketServer by simpler one and eliminate glue codes
I chose (b) because it's great time for getting rid of utterly complicated
SocketServer stuff, and preparing for future move towards prefork service.
New unixforkingservice is implemented loosely based on chg 531f8ef64be6. It
is monolithic but much simpler than SocketServer. unixservicehandler provides
customizing points for chg, and it will be shared with future prefork service.
Old unixservice class is still used by chgserver. It will be removed later.
Thanks to Jun Wu for investigating these issues.
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Sun, 22 May 2016 11:43:18 +0900 |
parents | 3f45488d70df |
children | 73c2b9c9cd3c |
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# A minimal client for Mercurial's command server from __future__ import absolute_import, print_function import os import signal import socket import struct import subprocess import sys import time try: import cStringIO as io stringio = io.StringIO except ImportError: import io stringio = io.StringIO def connectpipe(path=None): cmdline = ['hg', 'serve', '--cmdserver', 'pipe'] if path: cmdline += ['-R', path] server = subprocess.Popen(cmdline, stdin=subprocess.PIPE, stdout=subprocess.PIPE) return server class unixconnection(object): def __init__(self, sockpath): self.sock = sock = socket.socket(socket.AF_UNIX) sock.connect(sockpath) self.stdin = sock.makefile('wb') self.stdout = sock.makefile('rb') def wait(self): self.stdin.close() self.stdout.close() self.sock.close() class unixserver(object): def __init__(self, sockpath, logpath=None, repopath=None): self.sockpath = sockpath cmdline = ['hg', 'serve', '--cmdserver', 'unix', '-a', sockpath] if repopath: cmdline += ['-R', repopath] if logpath: stdout = open(logpath, 'a') stderr = subprocess.STDOUT else: stdout = stderr = None self.server = subprocess.Popen(cmdline, stdout=stdout, stderr=stderr) # wait for listen() while self.server.poll() is None: if os.path.exists(sockpath): break time.sleep(0.1) def connect(self): return unixconnection(self.sockpath) def shutdown(self): os.kill(self.server.pid, signal.SIGTERM) self.server.wait() def writeblock(server, data): server.stdin.write(struct.pack('>I', len(data))) server.stdin.write(data) server.stdin.flush() def readchannel(server): data = server.stdout.read(5) if not data: raise EOFError channel, length = struct.unpack('>cI', data) if channel in 'IL': return channel, length else: return channel, server.stdout.read(length) def sep(text): return text.replace('\\', '/') def runcommand(server, args, output=sys.stdout, error=sys.stderr, input=None, outfilter=lambda x: x): print('*** runcommand', ' '.join(args)) sys.stdout.flush() server.stdin.write('runcommand\n') writeblock(server, '\0'.join(args)) if not input: input = stringio() while True: ch, data = readchannel(server) if ch == 'o': output.write(outfilter(data)) output.flush() elif ch == 'e': error.write(data) error.flush() elif ch == 'I': writeblock(server, input.read(data)) elif ch == 'L': writeblock(server, input.readline(data)) elif ch == 'r': ret, = struct.unpack('>i', data) if ret != 0: print(' [%d]' % ret) return ret else: print("unexpected channel %c: %r" % (ch, data)) if ch.isupper(): return def check(func, connect=connectpipe): sys.stdout.flush() server = connect() try: return func(server) finally: server.stdin.close() server.wait()