##// END OF EJS Templates
worker: Use buffered input from the pickle stream...
worker: Use buffered input from the pickle stream On Python 3, "pickle.load" will raise an exception ("_pickle.UnpicklingError: pickle data was truncated") when it gets a short read, i.e. it receives fewer bytes than it requested. On our build machine, Mercurial seems to frequently hit this problem while updating a mozilla-central clone iff it gets scheduled in batch mode. It is easy to trigger with: #wipe the workdir rm -rf * hg update null chrt -b 0 hg update default I've also written the following program, which demonstrates the core problem: from __future__ import print_function import io import os import pickle import time obj = {"a": 1, "b": 2} obj_data = pickle.dumps(obj) assert len(obj_data) > 10 rfd, wfd = os.pipe() pid = os.fork() if pid == 0: os.close(rfd) for _ in range(4): time.sleep(0.5) print("First write") os.write(wfd, obj_data[:10]) time.sleep(0.5) print("Second write") os.write(wfd, obj_data[10:]) os._exit(0) try: os.close(wfd) rfile = os.fdopen(rfd, "rb", 0) print("Reading") while True: try: obj_copy = pickle.load(rfile) assert obj == obj_copy except EOFError: break print("Success") finally: os.kill(pid, 15) The program reliably fails with Python 3.8 and succeeds with Python 2.7. Providing the unpickler with a buffered reader fixes the issue, so let "os.fdopen" create one. https://bugzilla.mozilla.org/show_bug.cgi?id=1604486 Differential Revision: https://phab.mercurial-scm.org/D8051

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hgclient.py
163 lines | 4.0 KiB | text/x-python | PythonLexer
# A minimal client for Mercurial's command server
from __future__ import absolute_import, print_function
import io
import os
import re
import signal
import socket
import struct
import subprocess
import sys
import time
if sys.version_info[0] >= 3:
stdout = sys.stdout.buffer
stderr = sys.stderr.buffer
stringio = io.BytesIO
def bprint(*args):
# remove b'' as well for ease of test migration
pargs = [re.sub(br'''\bb(['"])''', br'\1', b'%s' % a) for a in args]
stdout.write(b' '.join(pargs) + b'\n')
else:
import cStringIO
stdout = sys.stdout
stderr = sys.stderr
stringio = cStringIO.StringIO
bprint = print
def connectpipe(path=None, extraargs=()):
cmdline = [b'hg', b'serve', b'--cmdserver', b'pipe']
if path:
cmdline += [b'-R', path]
cmdline.extend(extraargs)
def tonative(cmdline):
if os.name != 'nt':
return cmdline
return [arg.decode("utf-8") for arg in cmdline]
server = subprocess.Popen(
tonative(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 = [b'hg', b'serve', b'--cmdserver', b'unix', b'-a', sockpath]
if repopath:
cmdline += [b'-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(b'>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 b'IL':
return channel, length
else:
return channel, server.stdout.read(length)
def sep(text):
return text.replace(b'\\', b'/')
def runcommand(
server, args, output=stdout, error=stderr, input=None, outfilter=lambda x: x
):
bprint(b'*** runcommand', b' '.join(args))
stdout.flush()
server.stdin.write(b'runcommand\n')
writeblock(server, b'\0'.join(args))
if not input:
input = stringio()
while True:
ch, data = readchannel(server)
if ch == b'o':
output.write(outfilter(data))
output.flush()
elif ch == b'e':
error.write(data)
error.flush()
elif ch == b'I':
writeblock(server, input.read(data))
elif ch == b'L':
writeblock(server, input.readline(data))
elif ch == b'm':
bprint(b"message: %r" % data)
elif ch == b'r':
(ret,) = struct.unpack('>i', data)
if ret != 0:
bprint(b' [%d]' % ret)
return ret
else:
bprint(b"unexpected channel %c: %r" % (ch, data))
if ch.isupper():
return
def check(func, connect=connectpipe):
stdout.flush()
server = connect()
try:
return func(server)
finally:
server.stdin.close()
server.wait()
def checkwith(connect=connectpipe, **kwargs):
def wrap(func):
return check(func, lambda: connect(**kwargs))
return wrap