annotate hgext/blackbox.py @ 35506:fa865878a849

lfs: show a friendly message when pushing lfs to a server without lfs enabled

Upfront disclaimer: I don't know anything about the wire protocol, and this was
pretty much cargo-culted from largefiles, and then clonebundles, since it seems
more modern.  I was surprised that exchange.push() will ensure all of the proper
requirements when exchanging between two local repos, but doesn't care when one
is remote.

All this new capability marker does is inform the client that the extension is
enabled remotely.  It may or may not contain commits with external blobs.

Open issues:

  - largefiles uses 'largefiles=serve' for its capability.  Someday I hope to
    be able to push lfs blobs to an `hg serve` instance.  That will probably
    require a distinct capability.  Should it change to '=serve' then?  Or just
    add an 'lfs-serve' capability then?

  - The flip side of this is more complicated.  It looks like largefiles adds an
    'lheads' command for the client to signal to the server that the extension
    is loaded.  That is then converted to 'heads' and sent through the normal
    wire protocol plumbing.  A client using the 'heads' command directly is
    kicked out with a message indicating that the largefiles extension must be
    loaded.  We could do similar with 'lfsheads', but then a repo with both
    largefiles and lfs blobs can't be pushed over the wire.  Hopefully somebody
    with more wire protocol experience can think of something else.  I see
    'x-hgarg-1' on some commands in the tests, but not on heads, and didn't dig
    any further.

# 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 = *
  # dirty is *EXPENSIVE* (slow);
  # each log entry indicates `+` if the repository is dirty, like :hg:`id`.
  dirty = True
  # record the source of log messages
  logsource = True

  [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 __future__ import absolute_import

import errno
import re

from mercurial.i18n import _
from mercurial.node import hex

from mercurial import (
    registrar,
    ui as uimod,
    util,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' 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 = 'ships-with-hg-core'

cmdtable = {}
command = registrar.command(cmdtable)

configtable = {}
configitem = registrar.configitem(configtable)

configitem('blackbox', 'dirty',
    default=False,
)
configitem('blackbox', 'maxsize',
    default='1 MB',
)
configitem('blackbox', 'logsource',
    default=False,
)
configitem('blackbox', 'maxfiles',
    default=7,
)
configitem('blackbox', 'track',
    default=lambda: ['*'],
)

lastui = None

def _openlogfile(ui, vfs):
    def rotate(oldpath, newpath):
        try:
            vfs.unlink(newpath)
        except OSError as err:
            if err.errno != errno.ENOENT:
                ui.debug("warning: cannot remove '%s': %s\n" %
                         (newpath, err.strerror))
        try:
            if newpath:
                vfs.rename(oldpath, newpath)
        except OSError as err:
            if err.errno != errno.ENOENT:
                ui.debug("warning: cannot rename '%s' to '%s': %s\n" %
                         (newpath, oldpath, err.strerror))

    maxsize = ui.configbytes('blackbox', 'maxsize')
    name = 'blackbox.log'
    if maxsize > 0:
        try:
            st = vfs.stat(name)
        except OSError:
            pass
        else:
            if st.st_size >= maxsize:
                path = vfs.join(name)
                maxfiles = ui.configint('blackbox', 'maxfiles')
                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')
    return vfs(name, 'a')

def wrapui(ui):
    class blackboxui(ui.__class__):
        @property
        def _bbvfs(self):
            vfs = None
            repo = getattr(self, '_bbrepo', None)
            if repo:
                vfs = repo.vfs
                if not vfs.isdir('.'):
                    vfs = None
            return vfs

        @util.propertycache
        def track(self):
            return self.configlist('blackbox', 'track')

        def log(self, event, *msg, **opts):
            global lastui
            super(blackboxui, self).log(event, *msg, **opts)

            if not '*' in self.track and not event in self.track:
                return

            if self._bbvfs:
                ui = self
            else:
                # certain ui instances exist outside the context of
                # a repo, so just default to the last blackbox that
                # was seen.
                ui = lastui

            if not ui:
                return
            vfs = ui._bbvfs
            if not vfs:
                return

            repo = getattr(ui, '_bbrepo', None)
            if not lastui or repo:
                lastui = ui
            if getattr(ui, '_bbinlog', False):
                # recursion and failure guard
                return
            ui._bbinlog = True
            default = self.configdate('devel', 'default-date')
            date = util.datestr(default, '%Y/%m/%d %H:%M:%S')
            user = util.getuser()
            pid = '%d' % util.getpid()
            formattedmsg = msg[0] % msg[1:]
            rev = '(unknown)'
            changed = ''
            if repo:
                ctx = repo[None]
                parents = ctx.parents()
                rev = ('+'.join([hex(p.node()) for p in parents]))
                if (ui.configbool('blackbox', 'dirty') and
                    ctx.dirty(missing=True, merge=False, branch=False)):
                    changed = '+'
            if ui.configbool('blackbox', 'logsource'):
                src = ' [%s]' % event
            else:
                src = ''
            try:
                fmt = '%s %s @%s%s (%s)%s> %s'
                args = (date, user, rev, changed, pid, src, formattedmsg)
                with _openlogfile(ui, vfs) as fp:
                    fp.write(fmt % args)
            except (IOError, OSError) as err:
                self.debug('warning: cannot write to blackbox.log: %s\n' %
                           err.strerror)
                # do not restore _bbinlog intentionally to avoid failed
                # logging again
            else:
                ui._bbinlog = False

        def setrepo(self, repo):
            self._bbrepo = repo

    ui.__class__ = blackboxui
    uimod.ui = 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)

        # Set lastui even if ui.log is not called. This gives blackbox a
        # fallback place to log.
        global lastui
        if lastui is None:
            lastui = ui

    repo._wlockfreeprefix.add('blackbox.log')

@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 repo.vfs.exists('blackbox.log'):
        return

    limit = opts.get(r'limit')
    fp = repo.vfs('blackbox.log', 'r')
    lines = fp.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)))