Application: gvSIG desktop » gvSIG scripting

# log_utils.py -- Logging utilities for Dulwich

# Copyright (C) 2010 Google, Inc.

#

# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU

# General Public License as public by the Free Software Foundation; version 2.0

# or (at your option) any later version. You can redistribute it and/or

# modify it under the terms of either of these two licenses.

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

#

# You should have received a copy of the licenses; if not, see

# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License

# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache

# License, Version 2.0.

#

"""Logging utilities for Dulwich.

Any module that uses logging needs to do compile-time initialization to set up

the logging environment. Since Dulwich is also used as a library, clients may

not want to see any logging output. In that case, we need to use a special

handler to suppress spurious warnings like "No handlers could be found for

logger dulwich.foo".

For details on the _NullHandler approach, see:

http://docs.python.org/library/logging.html#configuring-logging-for-a-library

For many modules, the only function from the logging module they need is

getLogger; this module exports that function for convenience. If a calling

module needs something else, it can import the standard logging module directly.

"""

import logging

import sys

getLogger = logging.getLogger

class _NullHandler(logging.Handler):

    """No-op logging handler to avoid unexpected logging warnings."""

    def emit(self, record):

        pass

_NULL_HANDLER = _NullHandler()

_DULWICH_LOGGER = getLogger('dulwich')

_DULWICH_LOGGER.addHandler(_NULL_HANDLER)

def default_logging_config():

    """Set up the default Dulwich loggers."""

    remove_null_handler()

    logging.basicConfig(level=logging.INFO, stream=sys.stderr,

                        format='%(asctime)s %(levelname)s: %(message)s')

def remove_null_handler():

    """Remove the null handler from the Dulwich loggers.

    If a caller wants to set up logging using something other than

    default_logging_config, calling this function first is a minor optimization

    to avoid the overhead of using the _NullHandler.

    """

    _DULWICH_LOGGER.removeHandler(_NULL_HANDLER)