~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005-2011 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Messages and logging.

Messages are supplied by callers as a string-formatting template, plus values

to be inserted into it.  The actual %-formatting is deferred to the log

library so that it doesn't need to be done for messages that won't be emitted.

Messages are classified by severity levels: critical, error, warning, info,

and debug.

They can be sent to two places: to stderr, and to ~/.bzr.log.  For purposes

such as running the test suite, they can also be redirected away from both of

those two places to another location.

~/.bzr.log gets all messages, and full tracebacks for uncaught exceptions.

This trace file is always in UTF-8, regardless of the user's default encoding,

so that we can always rely on writing any message.

Output to stderr depends on the mode chosen by the user.  By default, messages

of info and above are sent out, which results in progress messages such as the

list of files processed by add and commit.  In debug mode, stderr gets debug messages too.

Errors that terminate an operation are generally passed back as exceptions;

others may be just emitted as messages.

Exceptions are reported in a brief form to stderr so as not to look scary.

BzrErrors are required to be able to format themselves into a properly

explanatory message.  This is not true for builtin exceptions such as

KeyError, which typically just str to "0".  They're printed in a different

form.

"""

from __future__ import absolute_import

# FIXME: Unfortunately it turns out that python's logging module

# is quite expensive, even when the message is not printed by any handlers.

# We should perhaps change back to just simply doing it here.

#

# On the other hand, as of 1.2 we generally only call the mutter() statement

# if (according to debug_flags) we actually intend to write it.  So the

# increased cost of logging.py is not so bad, and we could standardize on

# that.

import logging

import os

import sys

import time

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

from cStringIO import StringIO

import errno

import locale

import tempfile

import traceback

""")

import bzrlib

lazy_import(globals(), """

from bzrlib import (

    debug,

    errors,

    osutils,

    ui,

    )

""")

# global verbosity for bzrlib; controls the log level for stderr; 0=normal; <0

# is quiet; >0 is verbose.

_verbosity_level = 0

# File-like object where mutter/debug output is currently sent.  Can be

# changed by _push_log_file etc.  This is directly manipulated by some

# external code; maybe there should be functions to do that more precisely

# than push/pop_log_file.

_trace_file = None

# Absolute path for ~/.bzr.log.  Not changed even if the log/trace output is

# redirected elsewhere.  Used to show the location in --version.

_bzr_log_filename = None

# The time the first message was written to the trace file, so that we can

# show relative times since startup.

_bzr_log_start_time = bzrlib._start_time

# held in a global for quick reference

_bzr_logger = logging.getLogger('bzr')

def note(*args, **kwargs):

    """Output a note to the user.

    Takes the same parameters as logging.info.

    :return: None

    """

    # FIXME: clearing the ui and then going through the abstract logging

    # framework is whack; we should probably have a logging Handler that

    # deals with terminal output if needed.

    ui.ui_factory.clear_term()

    _bzr_logger.info(*args, **kwargs)

def warning(*args, **kwargs):

    ui.ui_factory.clear_term()

    _bzr_logger.warning(*args, **kwargs)

def show_error(*args, **kwargs):

    """Show an error message to the user.

    Don't use this for exceptions, use report_exception instead.

    """

    _bzr_logger.error(*args, **kwargs)

def mutter(fmt, *args):

    if _trace_file is None:

        return

    # XXX: Don't check this every time; instead anyone who closes the file

    # ought to deregister it.  We can tolerate None.

    if (getattr(_trace_file, 'closed', None) is not None) and _trace_file.closed:

        return

    if isinstance(fmt, unicode):

        fmt = fmt.encode('utf8')

    if len(args) > 0:

        # It seems that if we do ascii % (unicode, ascii) we can

        # get a unicode cannot encode ascii error, so make sure that "fmt"

        # is a unicode string

        real_args = []

        for arg in args:

            if isinstance(arg, unicode):

                arg = arg.encode('utf8')

            real_args.append(arg)

        out = fmt % tuple(real_args)

    else:

        out = fmt

    now = time.time()

    timestamp = '%0.3f  ' % (now - _bzr_log_start_time,)

    out = timestamp + out + '\n'

    _trace_file.write(out)

    # there's no explicit flushing; the file is typically line buffered.

def mutter_callsite(stacklevel, fmt, *args):

    """Perform a mutter of fmt and args, logging the call trace.

    :param stacklevel: The number of frames to show. None will show all

        frames.

    :param fmt: The format string to pass to mutter.

    :param args: A list of substitution variables.

    """

    outf = StringIO()

    if stacklevel is None:

        limit = None

    else:

        limit = stacklevel + 1

    traceback.print_stack(limit=limit, file=outf)

    formatted_lines = outf.getvalue().splitlines()

    formatted_stack = '\n'.join(formatted_lines[:-2])

    mutter(fmt + "\nCalled from:\n%s", *(args + (formatted_stack,)))

def _rollover_trace_maybe(trace_fname):

    import stat

    try:

        size = os.stat(trace_fname)[stat.ST_SIZE]

        if size <= 4 << 20:

            return

        old_fname = trace_fname + '.old'

        osutils.rename(trace_fname, old_fname)

    except OSError:

        return

def _get_bzr_log_filename():

    bzr_log = osutils.path_from_environ('BZR_LOG')

    if bzr_log:

        return bzr_log

    home = osutils.path_from_environ('BZR_HOME')

    if home is None:

        # GZ 2012-02-01: Logging to the home dir is bad, but XDG is unclear

        #                over what would be better. On windows, bug 240550

        #                suggests LOCALAPPDATA be used instead.

        home = osutils._get_home_dir()

    return os.path.join(home, '.bzr.log')

def _open_bzr_log():

    """Open the .bzr.log trace file.

    If the log is more than a particular length, the old file is renamed to

    .bzr.log.old and a new file is started.  Otherwise, we append to the

    existing file.

    This sets the global _bzr_log_filename.

    """

    global _bzr_log_filename

    def _open_or_create_log_file(filename):

        """Open existing log file, or create with ownership and permissions

        It inherits the ownership and permissions (masked by umask) from

        the containing directory to cope better with being run under sudo

        with $HOME still set to the user's homedir.

        """

        flags = os.O_WRONLY | os.O_APPEND | osutils.O_TEXT

        while True:

            try:

                fd = os.open(filename, flags)

                break

            except OSError, e:

                if e.errno != errno.ENOENT:

                    raise

            try:

                fd = os.open(filename, flags | os.O_CREAT | os.O_EXCL, 0666)

            except OSError, e:

                if e.errno != errno.EEXIST:

                    raise

            else:

                osutils.copy_ownership_from_path(filename)

                break

        return os.fdopen(fd, 'at', 0) # unbuffered

    _bzr_log_filename = _get_bzr_log_filename()

    _rollover_trace_maybe(_bzr_log_filename)

    try:

        bzr_log_file = _open_or_create_log_file(_bzr_log_filename)

        bzr_log_file.write('\n')

        if bzr_log_file.tell() <= 2:

            bzr_log_file.write("this is a debug log for diagnosing/reporting problems in bzr\n")

            bzr_log_file.write("you can delete or truncate this file, or include sections in\n")

            bzr_log_file.write("bug reports to https://bugs.launchpad.net/bzr/+filebug\n\n")

        return bzr_log_file

    except EnvironmentError, e:

        # If we are failing to open the log, then most likely logging has not

        # been set up yet. So we just write to stderr rather than using

        # 'warning()'. If we using warning(), users get the unhelpful 'no

        # handlers registered for "bzr"' when something goes wrong on the

        # server. (bug #503886)

        sys.stderr.write("failed to open trace file: %s\n" % (e,))

    # TODO: What should happen if we fail to open the trace file?  Maybe the

    # objects should be pointed at /dev/null or the equivalent?  Currently

    # returns None which will cause failures later.

    return None

def enable_default_logging():

    """Configure default logging: messages to stderr and debug to .bzr.log

    This should only be called once per process.

    Non-command-line programs embedding bzrlib do not need to call this.  They

    can instead either pass a file to _push_log_file, or act directly on

    logging.getLogger("bzr").

    Output can be redirected away by calling _push_log_file.

    :return: A memento from push_log_file for restoring the log state.

    """

    start_time = osutils.format_local_date(_bzr_log_start_time,

                                           timezone='local')

    bzr_log_file = _open_bzr_log()

    if bzr_log_file is not None:

        bzr_log_file.write(start_time.encode('utf-8') + '\n')

    memento = push_log_file(bzr_log_file,

        r'[%(process)5d] %(asctime)s.%(msecs)03d %(levelname)s: %(message)s',

        r'%Y-%m-%d %H:%M:%S')

    # after hooking output into bzr_log, we also need to attach a stderr

    # handler, writing only at level info and with encoding

    stderr_handler = EncodedStreamHandler(sys.stderr,

        osutils.get_terminal_encoding(), 'replace', level=logging.INFO)

    logging.getLogger('bzr').addHandler(stderr_handler)

    return memento

def push_log_file(to_file, log_format=None, date_format=None):

    """Intercept log and trace messages and send them to a file.

    :param to_file: A file-like object to which messages will be sent.

    :returns: A memento that should be passed to _pop_log_file to restore the

        previously active logging.

    """

    global _trace_file

    # make a new handler

    new_handler = EncodedStreamHandler(to_file, "utf-8", level=logging.DEBUG)

    if log_format is None:

        log_format = '%(levelname)8s  %(message)s'

    new_handler.setFormatter(logging.Formatter(log_format, date_format))

    # save and remove any existing log handlers

    bzr_logger = logging.getLogger('bzr')

    old_handlers = bzr_logger.handlers[:]

    del bzr_logger.handlers[:]

    # set that as the default logger

    bzr_logger.addHandler(new_handler)

    bzr_logger.setLevel(logging.DEBUG)

    # TODO: check if any changes are needed to the root logger

    #

    # TODO: also probably need to save and restore the level on bzr_logger.

    # but maybe we can avoid setting the logger level altogether, and just set

    # the level on the handler?

    #

    # save the old trace file

    old_trace_file = _trace_file

    # send traces to the new one

    _trace_file = to_file

    result = new_handler, _trace_file

    return ('log_memento', old_handlers, new_handler, old_trace_file, to_file)

def pop_log_file((magic, old_handlers, new_handler, old_trace_file, new_trace_file)):

    """Undo changes to logging/tracing done by _push_log_file.

    This flushes, but does not close the trace file (so that anything that was

    in it is output.

    Takes the memento returned from _push_log_file."""

    global _trace_file

    _trace_file = old_trace_file

    bzr_logger = logging.getLogger('bzr')

    bzr_logger.removeHandler(new_handler)

    # must be closed, otherwise logging will try to close it at exit, and the

    # file will likely already be closed underneath.

    new_handler.close()

    bzr_logger.handlers = old_handlers

    if new_trace_file is not None:

        new_trace_file.flush()

def log_exception_quietly():

    """Log the last exception to the trace file only.

    Used for exceptions that occur internally and that may be

    interesting to developers but not to users.  For example,

    errors loading plugins.

    """

    mutter(traceback.format_exc())

def set_verbosity_level(level):

    """Set the verbosity level.

    :param level: -ve for quiet, 0 for normal, +ve for verbose

    """

    global _verbosity_level

    _verbosity_level = level

    _update_logging_level(level < 0)

    ui.ui_factory.be_quiet(level < 0)

def get_verbosity_level():

    """Get the verbosity level.

    See set_verbosity_level() for values.

    """

    return _verbosity_level

def be_quiet(quiet=True):

    if quiet:

        set_verbosity_level(-1)

    else:

        set_verbosity_level(0)

def _update_logging_level(quiet=True):

    """Hide INFO messages if quiet."""

    if quiet:

        _bzr_logger.setLevel(logging.WARNING)

    else:

        _bzr_logger.setLevel(logging.INFO)

def is_quiet():

    """Is the verbosity level negative?"""

    return _verbosity_level < 0

def is_verbose():

    """Is the verbosity level positive?"""

    return _verbosity_level > 0

def debug_memory(message='', short=True):

    """Write out a memory dump."""

    if sys.platform == 'win32':

        from bzrlib import win32utils

        win32utils.debug_memory_win32api(message=message, short=short)

    else:

        _debug_memory_proc(message=message, short=short)

_short_fields = ('VmPeak', 'VmSize', 'VmRSS')

def _debug_memory_proc(message='', short=True):

    try:

        status_file = file('/proc/%s/status' % os.getpid(), 'rb')

    except IOError:

        return

    try:

        status = status_file.read()

    finally:

        status_file.close()

    if message:

        note(message)

    for line in status.splitlines():

        if not short:

            note(line)

        else:

            for field in _short_fields:

                if line.startswith(field):

                    note(line)

                    break

def _dump_memory_usage(err_file):

    try:

        try:

            fd, name = tempfile.mkstemp(prefix="bzr_memdump", suffix=".json")

            dump_file = os.fdopen(fd, 'w')

            from meliae import scanner

            scanner.dump_gc_objects(dump_file)

            err_file.write("Memory dumped to %s\n" % name)

        except ImportError:

            err_file.write("Dumping memory requires meliae module.\n")

            log_exception_quietly()

        except:

            err_file.write("Exception while dumping memory.\n")

            log_exception_quietly()

    finally:

        if dump_file is not None:

            dump_file.close()

        elif fd is not None:

            os.close(fd)

def _qualified_exception_name(eclass, unqualified_bzrlib_errors=False):

    """Give name of error class including module for non-builtin exceptions

    If `unqualified_bzrlib_errors` is True, errors specific to bzrlib will

    also omit the module prefix.

    """

    class_name = eclass.__name__

    module_name = eclass.__module__

    if module_name in ("exceptions", "__main__") or (

            unqualified_bzrlib_errors and module_name == "bzrlib.errors"):

        return class_name

    return "%s.%s" % (module_name, class_name)

def report_exception(exc_info, err_file):

    """Report an exception to err_file (typically stderr) and to .bzr.log.

    This will show either a full traceback or a short message as appropriate.

    :return: The appropriate exit code for this error.

    """

    # Log the full traceback to ~/.bzr.log

    log_exception_quietly()

    if 'error' in debug.debug_flags:

        print_exception(exc_info, err_file)

        return errors.EXIT_ERROR

    exc_type, exc_object, exc_tb = exc_info

    if isinstance(exc_object, KeyboardInterrupt):

        err_file.write("bzr: interrupted\n")

        return errors.EXIT_ERROR

    elif isinstance(exc_object, MemoryError):

        err_file.write("bzr: out of memory\n")

        if 'mem_dump' in debug.debug_flags:

            _dump_memory_usage(err_file)

        else:

            err_file.write("Use -Dmem_dump to dump memory to a file.\n")

        return errors.EXIT_ERROR

    elif isinstance(exc_object, ImportError) \

        and str(exc_object).startswith("No module named "):

        report_user_error(exc_info, err_file,

            'You may need to install this Python library separately.')

        return errors.EXIT_ERROR

    elif not getattr(exc_object, 'internal_error', True):

        report_user_error(exc_info, err_file)

        return errors.EXIT_ERROR

    elif osutils.is_environment_error(exc_object):

        if getattr(exc_object, 'errno', None) == errno.EPIPE:

            err_file.write("bzr: broken pipe\n")

            return errors.EXIT_ERROR

        # Might be nice to catch all of these and show them as something more

        # specific, but there are too many cases at the moment.

        report_user_error(exc_info, err_file)

        return errors.EXIT_ERROR

    else:

        report_bug(exc_info, err_file)

        return errors.EXIT_INTERNAL_ERROR

def print_exception(exc_info, err_file):

    exc_type, exc_object, exc_tb = exc_info

    err_file.write("bzr: ERROR: %s.%s: %s\n" % (

        exc_type.__module__, exc_type.__name__, exc_object))

    err_file.write('\n')

    traceback.print_exception(exc_type, exc_object, exc_tb, file=err_file)

# TODO: Should these be specially encoding the output?

def report_user_error(exc_info, err_file, advice=None):

    """Report to err_file an error that's not an internal error.

    These don't get a traceback unless -Derror was given.

    :param exc_info: 3-tuple from sys.exc_info()

    :param advice: Extra advice to the user to be printed following the

        exception.

    """

    err_file.write("bzr: ERROR: %s\n" % (exc_info[1],))

    if advice:

        err_file.write("%s\n" % (advice,))

def report_bug(exc_info, err_file):

    """Report an exception that probably indicates a bug in bzr"""

    from bzrlib.crash import report_bug

    report_bug(exc_info, err_file)

def _flush_stdout_stderr():

    # called from the bzrlib library finalizer returned by bzrlib.initialize()

    try:

        sys.stdout.flush()

        sys.stderr.flush()

    except ValueError, e:

        # On Windows, I get ValueError calling stdout.flush() on a closed

        # handle

        pass

    except IOError, e:

        import errno

        if e.errno in [errno.EINVAL, errno.EPIPE]:

            pass

        else:

            raise

def _flush_trace():

    # called from the bzrlib library finalizer returned by bzrlib.initialize()

    global _trace_file

    if _trace_file:

        _trace_file.flush()

class EncodedStreamHandler(logging.Handler):

    """Robustly write logging events to a stream using the specified encoding

    Messages are expected to be formatted to unicode, but UTF-8 byte strings

    are also accepted. An error during formatting or a str message in another

    encoding will be quitely noted as an error in the Bazaar log file.

    The stream is not closed so sys.stdout or sys.stderr may be passed.

    """

    def __init__(self, stream, encoding=None, errors='strict', level=0):

        logging.Handler.__init__(self, level)

        self.stream = stream

        if encoding is None:

            encoding = getattr(stream, "encoding", "ascii")

        self.encoding = encoding

        self.errors = errors

    def flush(self):

        flush = getattr(self.stream, "flush", None)

        if flush is not None:

            flush()

    def emit(self, record):

        try:

            line = self.format(record)

            if not isinstance(line, unicode):

                line = line.decode("utf-8")

            self.stream.write(line.encode(self.encoding, self.errors) + "\n")

        except Exception:

            log_exception_quietly()

            # Try saving the details that would have been logged in some form

            msg = args = "<Unformattable>"

            try:

                msg = repr(record.msg).encode("ascii")

                args = repr(record.args).encode("ascii")

            except Exception:

                pass

            # Using mutter() bypasses the logging module and writes directly

            # to the file so there's no danger of getting into a loop here.

            mutter("Logging record unformattable: %s %% %s", msg, args)

class Config(object):

    """Configuration of message tracing in bzrlib.

    This implements the context manager protocol and should manage any global

    variables still used. The default config used is DefaultConfig, but

    embedded uses of bzrlib may wish to use a custom manager.

    """

    def __enter__(self):

        return self # This is bound to the 'as' clause in a with statement.

    def __exit__(self, exc_type, exc_val, exc_tb):

        return False # propogate exceptions.

class DefaultConfig(Config):

    """A default configuration for tracing of messages in bzrlib.

    This implements the context manager protocol.

    """

    def __enter__(self):

        self._original_filename = _bzr_log_filename

        self._original_state = enable_default_logging()

        return self # This is bound to the 'as' clause in a with statement.

    def __exit__(self, exc_type, exc_val, exc_tb):

        pop_log_file(self._original_state)

        global _bzr_log_filename

        _bzr_log_filename = self._original_filename

        return False # propogate exceptions.