225
238
except (errors.TransportError, PathError), e:
226
239
self._trace("... failed to create pending dir, %s", e)
227
240
raise LockFailed(self, e)
229
self.transport.rename(tmpname, self._held_dir)
230
except (errors.TransportError, PathError, DirectoryNotEmpty,
231
FileExists, ResourceBusy), e:
232
self._trace("... contention, %s", e)
233
self._remove_pending_dir(tmpname)
234
raise LockContention(self)
236
self._trace("... lock failed, %s", e)
237
self._remove_pending_dir(tmpname)
243
self.transport.rename(tmpname, self._held_dir)
245
except (errors.TransportError, PathError, DirectoryNotEmpty,
246
FileExists, ResourceBusy), e:
247
self._trace("... contention, %s", e)
248
other_holder = self.peek()
249
self._trace("other holder is %r" % other_holder)
251
self._handle_lock_contention(other_holder)
253
self._remove_pending_dir(tmpname)
256
self._trace("... lock failed, %s", e)
257
self._remove_pending_dir(tmpname)
239
259
# We must check we really got the lock, because Launchpad's sftp
240
260
# server at one time had a bug were the rename would successfully
241
261
# move the new directory into the existing directory, which was
261
281
(time.time() - start_time) * 1000)
262
282
return self.nonce
284
def _handle_lock_contention(self, other_holder):
285
"""A lock we want to take is held by someone else.
287
This function can: tell the user about it; possibly detect that it's
288
safe or appropriate to steal the lock, or just raise an exception.
290
If this function returns (without raising an exception) the lock will
293
:param other_holder: A LockHeldInfo for the current holder; note that
294
it might be None if the lock can be seen to be held but the info
297
if (other_holder is not None):
298
if other_holder.is_lock_holder_known_dead():
299
if self.get_config().get('locks.steal_dead'):
300
ui.ui_factory.show_user_warning(
302
lock_url=urlutils.join(self.transport.base, self.path),
303
other_holder_info=unicode(other_holder))
304
self.force_break(other_holder)
305
self._trace("stole lock from dead holder")
307
raise LockContention(self)
264
309
def _remove_pending_dir(self, tmpname):
265
310
"""Remove the pending directory
343
388
def break_lock(self):
344
389
"""Break a lock not held by this instance of LockDir.
346
This is a UI centric function: it uses the bzrlib.ui.ui_factory to
391
This is a UI centric function: it uses the ui.ui_factory to
347
392
prompt for input if a lock is detected and there is any doubt about
348
it possibly being still active.
393
it possibly being still active. force_break is the non-interactive
396
:returns: LockResult for the broken lock.
350
398
self._check_not_locked()
351
holder_info = self.peek()
400
holder_info = self.peek()
401
except LockCorrupt, e:
402
# The lock info is corrupt.
403
if ui.ui_factory.get_boolean(u"Break (corrupt %r)" % (self,)):
404
self.force_break_corrupt(e.file_data)
352
406
if holder_info is not None:
353
lock_info = '\n'.join(self._format_lock_info(holder_info))
354
if bzrlib.ui.ui_factory.get_boolean("Break %s" % lock_info):
355
self.force_break(holder_info)
407
if ui.ui_factory.confirm_action(
408
u"Break %(lock_info)s",
409
'bzrlib.lockdir.break',
410
dict(lock_info=unicode(holder_info))):
411
result = self.force_break(holder_info)
412
ui.ui_factory.show_message(
413
"Broke lock %s" % result.lock_url)
357
415
def force_break(self, dead_holder_info):
358
416
"""Release a lock held by another process.
361
419
it still thinks it has the lock there will be two concurrent writers.
362
420
In general the user's approval should be sought for lock breaks.
364
dead_holder_info must be the result of a previous LockDir.peek() call;
365
this is used to check that it's still held by the same process that
366
the user decided was dead. If this is not the current holder,
367
LockBreakMismatch is raised.
369
422
After the lock is broken it will not be held by any process.
370
423
It is possible that another process may sneak in and take the
371
424
lock before the breaking process acquires it.
426
:param dead_holder_info:
427
Must be the result of a previous LockDir.peek() call; this is used
428
to check that it's still held by the same process that the user
429
decided was dead. If this is not the current holder,
430
LockBreakMismatch is raised.
432
:returns: LockResult for the broken lock.
373
if not isinstance(dead_holder_info, dict):
434
if not isinstance(dead_holder_info, LockHeldInfo):
374
435
raise ValueError("dead_holder_info: %r" % dead_holder_info)
375
436
self._check_not_locked()
376
437
current_info = self.peek()
394
455
current_info.get('nonce'))
395
456
for hook in self.hooks['lock_broken']:
460
def force_break_corrupt(self, corrupt_info_lines):
461
"""Release a lock that has been corrupted.
463
This is very similar to force_break, it except it doesn't assume that
464
self.peek() can work.
466
:param corrupt_info_lines: the lines of the corrupted info file, used
467
to check that the lock hasn't changed between reading the (corrupt)
468
info file and calling force_break_corrupt.
470
# XXX: this copes with unparseable info files, but what about missing
471
# info files? Or missing lock dirs?
472
self._check_not_locked()
473
tmpname = '%s/broken.%s.tmp' % (self.path, rand_chars(20))
474
self.transport.rename(self._held_dir, tmpname)
475
# check that we actually broke the right lock, not someone else;
476
# there's a small race window between checking it and doing the
478
broken_info_path = tmpname + self.__INFO_NAME
479
broken_content = self.transport.get_bytes(broken_info_path)
480
broken_lines = osutils.split_lines(broken_content)
481
if broken_lines != corrupt_info_lines:
482
raise LockBreakMismatch(self, broken_lines, corrupt_info_lines)
483
self.transport.delete(broken_info_path)
484
self.transport.rmdir(tmpname)
485
result = lock.LockResult(self.transport.abspath(self.path))
486
for hook in self.hooks['lock_broken']:
398
489
def _check_not_locked(self):
399
490
"""If the lock is held by this instance, raise an error."""
536
617
start = 'Lock owner changed for'
537
618
last_info = new_info
538
formatted_info = self._format_lock_info(new_info)
619
msg = u'%s lock %s %s.' % (start, lock_url, new_info)
539
620
if deadline_str is None:
540
621
deadline_str = time.strftime('%H:%M:%S',
541
time.localtime(deadline))
542
lock_url = self.transport.abspath(self.path)
543
# See <https://bugs.edge.launchpad.net/bzr/+bug/250451>
544
# the URL here is sometimes not one that is useful to the
545
# user, perhaps being wrapped in a lp-%d or chroot decorator,
546
# especially if this error is issued from the server.
547
self._report_function('%s %s\n'
549
'%s\n' # locked ... ago
550
'Will continue to try until %s, unless '
551
'you press Ctrl-C.\n'
552
'See "bzr help break-lock" for more.',
622
time.localtime(deadline))
624
msg += ('\nWill continue to try until %s, unless '
627
msg += '\nSee "bzr help break-lock" for more.'
628
self._report_function(msg)
560
629
if (max_attempts is not None) and (attempt_count >= max_attempts):
561
630
self._trace("exceeded %d attempts")
562
631
raise LockContention(self)
646
703
if 'lock' not in debug.debug_flags:
648
705
mutter(str(self) + ": " + (format % args))
707
def get_config(self):
708
"""Get the configuration that governs this lockdir."""
709
# XXX: This really should also use the locationconfig at least, but
710
# that seems a bit hard to hook up at the moment. -- mbp 20110329
711
# FIXME: The above is still true ;) -- vila 20110811
712
return config.GlobalStack()
715
class LockHeldInfo(object):
716
"""The information recorded about a held lock.
718
This information is recorded into the lock when it's taken, and it can be
719
read back by any process with access to the lockdir. It can be used, for
720
example, to tell the user who holds the lock, or to try to detect whether
721
the lock holder is still alive.
723
Prior to bzr 2.4 a simple dict was used instead of an object.
726
def __init__(self, info_dict):
727
self.info_dict = info_dict
730
"""Return a debugging representation of this object."""
731
return "%s(%r)" % (self.__class__.__name__, self.info_dict)
733
def __unicode__(self):
734
"""Return a user-oriented description of this object."""
735
d = self.to_readable_dict()
737
u'held by %(user)s on %(hostname)s (process #%(pid)s), '
738
u'acquired %(time_ago)s' % d)
740
def to_readable_dict(self):
741
"""Turn the holder info into a dict of human-readable attributes.
743
For example, the start time is presented relative to the current time,
744
rather than as seconds since the epoch.
746
Returns a list of [user, hostname, pid, time_ago] all as readable
749
start_time = self.info_dict.get('start_time')
750
if start_time is None:
751
time_ago = '(unknown)'
753
time_ago = format_delta(
754
time.time() - int(self.info_dict['start_time']))
755
user = self.info_dict.get('user', '<unknown>')
756
hostname = self.info_dict.get('hostname', '<unknown>')
757
pid = self.info_dict.get('pid', '<unknown>')
764
def get(self, field_name):
765
"""Return the contents of a field from the lock info, or None."""
766
return self.info_dict.get(field_name)
769
def for_this_process(cls, extra_holder_info):
770
"""Return a new LockHeldInfo for a lock taken by this process.
773
hostname=get_host_name(),
774
pid=str(os.getpid()),
775
nonce=rand_chars(20),
776
start_time=str(int(time.time())),
777
user=get_username_for_lock_info(),
779
if extra_holder_info is not None:
780
info.update(extra_holder_info)
784
s = rio.Stanza(**self.info_dict)
788
def from_info_file_bytes(cls, info_file_bytes):
789
"""Construct from the contents of the held file."""
790
lines = osutils.split_lines(info_file_bytes)
792
stanza = rio.read_stanza(lines)
793
except ValueError, e:
794
mutter('Corrupt lock info file: %r', lines)
795
raise LockCorrupt("could not parse lock info file: " + str(e),
798
# see bug 185013; we fairly often end up with the info file being
799
# empty after an interruption; we could log a message here but
800
# there may not be much we can say
803
return cls(stanza.as_dict())
805
def __cmp__(self, other):
806
"""Value comparison of lock holders."""
808
cmp(type(self), type(other))
809
or cmp(self.info_dict, other.info_dict))
811
def is_locked_by_this_process(self):
812
"""True if this process seems to be the current lock holder."""
814
self.get('hostname') == get_host_name()
815
and self.get('pid') == str(os.getpid())
816
and self.get('user') == get_username_for_lock_info())
818
def is_lock_holder_known_dead(self):
819
"""True if the lock holder process is known to be dead.
821
False if it's either known to be still alive, or if we just can't tell.
823
We can be fairly sure the lock holder is dead if it declared the same
824
hostname and there is no process with the given pid alive. If people
825
have multiple machines with the same hostname this may cause trouble.
827
This doesn't check whether the lock holder is in fact the same process
828
calling this method. (In that case it will return true.)
830
if self.get('hostname') != get_host_name():
832
if self.get('hostname') == 'localhost':
835
if self.get('user') != get_username_for_lock_info():
836
# Could well be another local process by a different user, but
837
# just to be safe we won't conclude about this either.
839
pid_str = self.info_dict.get('pid', None)
841
mutter("no pid recorded in %r" % (self, ))
846
mutter("can't parse pid %r from %r"
849
return osutils.is_local_pid_dead(pid)
852
def get_username_for_lock_info():
853
"""Get a username suitable for putting into a lock.
855
It's ok if what's written here is not a proper email address as long
856
as it gives some clue who the user is.
859
return config.GlobalConfig().username()
860
except errors.NoWhoami:
861
return osutils.getuser_unicode()
added
removed
bzrlib/lockdir.py
