##// END OF EJS Templates
hg: obtain lock when creating share from pooled repo (issue5104)...
hg: obtain lock when creating share from pooled repo (issue5104) There are race conditions between clients performing a shared clone to pooled storage: 1) Clients race to create the new shared repo in the pool directory 2) 1 client is seeding the repo in the pool directory and another goes to share it before it is fully cloned We prevent these race conditions by obtaining a lock in the pool directory that is derived from the name of the repo we will be accessing. To test this, a simple generic "lockdelay" extension has been added. The extension inserts an optional, configurable delay before or after lock acquisition. In the test, we delay 2 seconds after lock acquisition in the first process and 1 second before lock acquisition in the 2nd process. This means the first process has 1s to obtain the lock. There is a race condition here. If we encounter it in the wild, we could change the dummy extension to wait on the lock file to appear instead of relying on timing. But that's more complicated. Let's see what happens first.

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r26587:56b2bcea default
r28289:d493d647 3.7.2 stable
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remotestore.py
98 lines | 3.3 KiB | text/x-python | PythonLexer
# Copyright 2010-2011 Fog Creek Software
# Copyright 2010-2011 Unity Technologies
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''remote largefile store; the base class for wirestore'''
import urllib2
from mercurial import util, wireproto, error
from mercurial.i18n import _
import lfutil
import basestore
class remotestore(basestore.basestore):
'''a largefile store accessed over a network'''
def __init__(self, ui, repo, url):
super(remotestore, self).__init__(ui, repo, url)
def put(self, source, hash):
if self.sendfile(source, hash):
raise error.Abort(
_('remotestore: could not put %s to remote store %s')
% (source, util.hidepassword(self.url)))
self.ui.debug(
_('remotestore: put %s to remote store %s\n')
% (source, util.hidepassword(self.url)))
def exists(self, hashes):
return dict((h, s == 0) for (h, s) in # dict-from-generator
self._stat(hashes).iteritems())
def sendfile(self, filename, hash):
self.ui.debug('remotestore: sendfile(%s, %s)\n' % (filename, hash))
fd = None
try:
fd = lfutil.httpsendfile(self.ui, filename)
return self._put(hash, fd)
except IOError as e:
raise error.Abort(
_('remotestore: could not open file %s: %s')
% (filename, str(e)))
finally:
if fd:
fd.close()
def _getfile(self, tmpfile, filename, hash):
try:
chunks = self._get(hash)
except urllib2.HTTPError as e:
# 401s get converted to error.Aborts; everything else is fine being
# turned into a StoreError
raise basestore.StoreError(filename, hash, self.url, str(e))
except urllib2.URLError as e:
# This usually indicates a connection problem, so don't
# keep trying with the other files... they will probably
# all fail too.
raise error.Abort('%s: %s' %
(util.hidepassword(self.url), e.reason))
except IOError as e:
raise basestore.StoreError(filename, hash, self.url, str(e))
return lfutil.copyandhash(chunks, tmpfile)
def _verifyfile(self, cctx, cset, contents, standin, verified):
filename = lfutil.splitstandin(standin)
if not filename:
return False
fctx = cctx[standin]
key = (filename, fctx.filenode())
if key in verified:
return False
verified.add(key)
expecthash = fctx.data()[0:40]
stat = self._stat([expecthash])[expecthash]
if not stat:
return False
elif stat == 1:
self.ui.warn(
_('changeset %s: %s: contents differ\n')
% (cset, filename))
return True # failed
elif stat == 2:
self.ui.warn(
_('changeset %s: %s missing\n')
% (cset, filename))
return True # failed
else:
raise RuntimeError('verify failed: unexpected response from '
'statlfile (%r)' % stat)
def batch(self):
'''Support for remote batching.'''
return wireproto.remotebatch(self)