# 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

  [blackbox]

  # Include nanoseconds in log entries with %f (see Python function

  # datetime.datetime.strftime)

  date-format = '%Y-%m-%d @ %H:%M:%S.%f'

"""

from __future__ import absolute_import

import errno

import re

from mercurial.i18n import _

from mercurial.node import hex

from mercurial import (

    encoding,

    pycompat,

    registrar,

)

from mercurial.utils import (

    dateutil,

    procutil,

)

# 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: ['*'],

)

configitem('blackbox', 'date-format',

    default='%Y/%m/%d %H:%M:%S',

)

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 pycompat.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')

class proxylogger(object):

    """Forward log events to another logger to be set later"""

    def __init__(self):

        self.logger = None

    def tracked(self, event):

        return self.logger is not None and self.logger.tracked(event)

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

        assert self.logger is not None

        self.logger.log(ui, event, msg, opts)

_lastlogger = proxylogger()

class blackboxlogger(object):

    def __init__(self, ui, repo):

        self._repo = repo

        self._trackedevents = set(ui.configlist('blackbox', 'track'))

    def tracked(self, event):

        return b'*' in self._trackedevents or event in self._trackedevents

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

        default = ui.configdate('devel', 'default-date')

        date = dateutil.datestr(default, ui.config('blackbox', 'date-format'))

        user = procutil.getuser()

        pid = '%d' % procutil.getpid()

        rev = '(unknown)'

        changed = ''

        ctx = self._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, msg)

                fp.write(fmt % args)

        except (IOError, OSError) as err:

            # deactivate this to avoid failed logging again

            self._trackedevents.clear()

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

                     encoding.strtolocal(err.strerror))

def uipopulate(ui):

    ui.setlogger(b'blackbox', _lastlogger)

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

    # Since blackbox.log is stored in the repo directory, the logger should be

    # instantiated per repository.

    logger = blackboxlogger(ui, repo)

    ui.setlogger(b'blackbox', logger)

    # Set _lastlogger even if ui.log is not called. This gives blackbox a

    # fallback place to log

    if _lastlogger.logger is None:

        _lastlogger.logger = logger

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

@command('blackbox',

    [('l', 'limit', 10, _('the number of events to show')),

    ],

    _('hg blackbox [OPTION]...'),

    helpcategory=command.CATEGORY_MAINTENANCE,

    helpbasic=True)

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)))