# 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 __future__ import absolute_import

import errno

import re

from mercurial.i18n import _

from mercurial import (

    cmdutil,

    util,

)

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'

lastfp = None

filehandles = {}

def _openlog(vfs):

    path = vfs.join('blackbox.log')

    if path in filehandles:

        return filehandles[path]

    filehandles[path] = fp = vfs('blackbox.log', 'a')

    return fp

def _closelog(vfs):

    path = vfs.join('blackbox.log')

    fp = filehandles[path]

    del filehandles[path]

    fp.close()

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:

                    self._bbvfs.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:

                        self._bbvfs.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 = _openlog(self._bbvfs)

            maxsize = self.configbytes('blackbox', 'maxsize', 1048576)

            if maxsize > 0:

                st = self._bbvfs.fstat(fp)

                if st.st_size >= maxsize:

                    path = fp.name

                    _closelog(self._bbvfs)

                    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 = _openlog(self._bbvfs)

            return fp

        def log(self, event, *msg, **opts):

            global lastfp

            super(blackboxui, self).log(event, *msg, **opts)

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

                return

            if util.safehasattr(self, '_blackbox'):

                fp = self._blackbox

            elif util.safehasattr(self, '_bbvfs'):

                try:

                    self._bbfp = self._openlogfile()

                except (IOError, OSError) as err:

                    self.debug('warning: cannot write to blackbox.log: %s\n' %

                               err.strerror)

                    del self._bbvfs

                    self._bbfp = None

                fp = self._bbfp

            else:

                # certain ui instances exist outside the context of

                # a repo, so just default to the last blackbox that

                # was seen.

                fp = lastfp

            if fp:

                date = util.datestr(None, '%Y/%m/%d %H:%M:%S')

                user = util.getuser()

                pid = str(util.getpid())

                formattedmsg = msg[0] % msg[1:]

                try:

                    fp.flush()

                except IOError as err:

                    self.debug('warning: cannot write to blackbox.log: %s\n' %

                               err.strerror)

        def setrepo(self, repo):

            self._bbvfs = 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 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)))