# 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,

)

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', 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')

    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):

        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('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)))