commands: add debugdeltachain command
We have debug commands for displaying overall revlog statistics
(debugrevlog) and for dumping a revlog index (debugindex). As part
of investigating various aspects of revlog behavior and performance,
I found it important to have an understanding of how revlog
delta chains behave in practice.
This patch implements a "debugdeltachain" command. For each revision
in a revlog, it dumps information about the delta chain. Which delta
chain it is part of, length of the delta chain, distance since base
revision, info about base revision, size of the delta chain, etc. The
generic formatting facility is used, which means we can templatize
output and get machine readable output like JSON.
This command has already uncovered some weird history in
mozilla-central I didn't know about. So I think it's valuable.
# blackbox.py - log repository events to a file for post-mortem debugging
#
# Copyright 2010 Nicolas Dumazet
# Copyright 2013 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""log repository events to a blackbox for debugging
Logs event information to .hg/blackbox.log to help debug and diagnose problems.
The events that get logged can be configured via the blackbox.track config key.
Examples::
[blackbox]
track = *
[blackbox]
track = command, commandfinish, commandexception, exthook, pythonhook
[blackbox]
track = incoming
[blackbox]
# limit the size of a log file
maxsize = 1.5 MB
# rotate up to N log files when the current one gets too big
maxfiles = 3
"""
from mercurial import util, cmdutil
from mercurial.i18n import _
import errno, os, re
cmdtable = {}
command = cmdutil.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'internal' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'internal'
lastblackbox = None
def wrapui(ui):
class blackboxui(ui.__class__):
@util.propertycache
def track(self):
return self.configlist('blackbox', 'track', ['*'])
def _openlogfile(self):
def rotate(oldpath, newpath):
try:
os.unlink(newpath)
except OSError as err:
if err.errno != errno.ENOENT:
self.debug("warning: cannot remove '%s': %s\n" %
(newpath, err.strerror))
try:
if newpath:
os.rename(oldpath, newpath)
except OSError as err:
if err.errno != errno.ENOENT:
self.debug("warning: cannot rename '%s' to '%s': %s\n" %
(newpath, oldpath, err.strerror))
fp = self._bbopener('blackbox.log', 'a')
maxsize = self.configbytes('blackbox', 'maxsize', 1048576)
if maxsize > 0:
st = os.fstat(fp.fileno())
if st.st_size >= maxsize:
path = fp.name
fp.close()
maxfiles = self.configint('blackbox', 'maxfiles', 7)
for i in xrange(maxfiles - 1, 1, -1):
rotate(oldpath='%s.%d' % (path, i - 1),
newpath='%s.%d' % (path, i))
rotate(oldpath=path,
newpath=maxfiles > 0 and path + '.1')
fp = self._bbopener('blackbox.log', 'a')
return fp
def log(self, event, *msg, **opts):
global lastblackbox
super(blackboxui, self).log(event, *msg, **opts)
if not '*' in self.track and not event in self.track:
return
if util.safehasattr(self, '_blackbox'):
blackbox = self._blackbox
elif util.safehasattr(self, '_bbopener'):
try:
self._blackbox = self._openlogfile()
except (IOError, OSError) as err:
self.debug('warning: cannot write to blackbox.log: %s\n' %
err.strerror)
del self._bbopener
self._blackbox = None
blackbox = self._blackbox
else:
# certain ui instances exist outside the context of
# a repo, so just default to the last blackbox that
# was seen.
blackbox = lastblackbox
if blackbox:
date = util.datestr(None, '%Y/%m/%d %H:%M:%S')
user = util.getuser()
pid = str(os.getpid())
formattedmsg = msg[0] % msg[1:]
try:
blackbox.write('%s %s (%s)> %s' %
(date, user, pid, formattedmsg))
except IOError as err:
self.debug('warning: cannot write to blackbox.log: %s\n' %
err.strerror)
lastblackbox = blackbox
def setrepo(self, repo):
self._bbopener = repo.vfs
ui.__class__ = blackboxui
def uisetup(ui):
wrapui(ui)
def reposetup(ui, repo):
# During 'hg pull' a httppeer repo is created to represent the remote repo.
# It doesn't have a .hg directory to put a blackbox in, so we don't do
# the blackbox setup for it.
if not repo.local():
return
if util.safehasattr(ui, 'setrepo'):
ui.setrepo(repo)
@command('^blackbox',
[('l', 'limit', 10, _('the number of events to show')),
],
_('hg blackbox [OPTION]...'))
def blackbox(ui, repo, *revs, **opts):
'''view the recent repository events
'''
if not os.path.exists(repo.join('blackbox.log')):
return
limit = opts.get('limit')
blackbox = repo.vfs('blackbox.log', 'r')
lines = blackbox.read().split('\n')
count = 0
output = []
for line in reversed(lines):
if count >= limit:
break
# count the commands by matching lines like: 2013/01/23 19:13:36 root>
if re.match('^\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2} .*> .*', line):
count += 1
output.append(line)
ui.status('\n'.join(reversed(output)))