utils.py

# -*- coding: utf-8 -*-
"""
Utilities.

For now: a logger.

The logger has two possible behaviours, based on the DEBUG setting.

If DEBUG is true, the logger prints to stdout.
See: http://stackoverflow.com/questions/2302315/how-can-info-and-debug-logging-message-be-sent-to-stdout-and-higher-level-messag#answer-9323805

If DEBUG is false, the logger logs to a MongoDB database.
In this way, it is easy to keep all the logs in one place,
and show them in a web-based monitoring application.

The code for the MongoDB logger is taken from https://github.com/puentesarrin/mongodb-log
See LICENSE info below.
"""

import sys
import logging
import getpass

from bson import InvalidDocument
from datetime import datetime
from pymongo.collection import Collection
from socket import gethostname

from settings import DEBUG

try:
    from pymongo import MongoClient as Connection
except ImportError:
    from pymongo import Connection

if sys.version_info[0] >= 3:
    unicode = str

class MongoFormatter(logging.Formatter):
    def format(self, record):
        """Format exception object as a string"""
        data = record.__dict__.copy()

        if record.args:
            msg = record.msg % record.args
        else:
            msg = record.msg

        data.update(
            username=getpass.getuser(),
            time=datetime.now(),
            host=gethostname(),
            message=msg,
            args=tuple(unicode(arg) for arg in record.args)
        )
        if 'exc_info' in data and data['exc_info']:
            data['exc_info'] = self.formatException(data['exc_info'])
        return data


class MongoHandler(logging.Handler):
    """ Custom log handler

    Logs all messages to a mongo collection. This  handler is
    designed to be used with the standard python logging mechanism.
    """

    @classmethod
    def to(cls, collection, db='mongolog', host='localhost', port=None,
        username=None, password=None, level=logging.NOTSET):
        """ Create a handler for a given  """
        return cls(collection, db, host, port, username, password, level)

    def __init__(self, collection, db='mongolog', host='localhost', port=None,
        username=None, password=None, level=logging.NOTSET):
        """ Init log handler and store the collection handle """
        logging.Handler.__init__(self, level)
        if isinstance(collection, str):
            connection = Connection(host, port)
            if username and password:
                connection[db].authenticate(username, password)
            self.collection = connection[db][collection]
        elif isinstance(collection, Collection):
            self.collection = collection
        else:
            raise TypeError('collection must be an instance of basestring or '
                             'Collection')
        self.formatter = MongoFormatter()

    def emit(self, record):
        """ Store the record to the collection. Async insert """
        try:
            self.collection.insert(self.format(record))
        except InvalidDocument as e:
            logging.error("Unable to save log record: %s", e.message,
                exc_info=True)

logger = logging.getLogger('Радуга')
logger.setLevel(logging.DEBUG)

if DEBUG:
    ch = logging.StreamHandler( sys.__stdout__ )
    ch.setLevel(logging.DEBUG)
    
    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
    ch.setFormatter(formatter)
    
    logger.addHandler(ch)
else:
    logger.addHandler(MongoHandler.to(db='raduga', collection='log'))

"""
Copyright (c) 2009, Andrei Savu. All rights reserved.
 
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
 
   * Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.
 
   * Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""