source: main/waeup.sirp/trunk/src/waeup/sirp/utils/logger.py @ 6480

##
## logging.py
## Login : <uli@pu.smp.net>
## Started on  Mon Jun 13 01:25:07 2011 Uli Fouquet
## $Id$
## 
## Copyright (C) 2011 Uli Fouquet
## 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##
"""
Convenience stuff for logging.
"""
import os
import grok
import logging
from zope.interface import Interface, Attribute

class ISiteLoggers(Interface):

    loggers = Attribute("A list or generator of registered WAeUPLoggers")

    def register(name, filename=None, site=None, **options):
        """Register a logger `name` which logs to `filename`.

        If `filename` is not given, logfile will be `name` with
        ``.log`` as filename extension.
        """

    def unregister(name):
        """Unregister a once registered logger.
        """

class SiteLoggers(object):

    grok.implements(ISiteLoggers)

    @property
    def loggers(self):
        return self._loggers.values()

    def __init__(self):
        self._loggers = dict()

    def getLogger(self, filename):
        waeup_logger = self._loggers.get(filename, None)
        return waeup_logger.logger

    def register(self, loggername, filename=None, site=None, **kw):
        if loggername in self._loggers.keys():
            raise KeyError('Logger "%s" exists already.' % loggername)
        self._loggers[loggername] = WAeUPLogger(
            loggername, filename=filename, site=site, **kw)
        return

    def unregister(self, name):
        if name in self._loggers.keys():
            del self._loggers[name]
        return

    def keys(self):
        return self._loggers.keys()

class ILogger(Interface):
    """A logger cares for setup, update and restarting of a Python logger.
    """

    logger = Attribute("""A :class:`logging.Logger` instance""")


    def __init__(name, filename=None, site=None, **options):
        """Create a WAeUP logger instance.
        """
        pass

    def setup():
        """Create a Python :class:`logging.Logger` instance.

        The created logger is based on the params given by constructor.
        """
        pass

    def update(**options):
        """Update the logger.

        Updates the logger respecting modified `options` and changed
        paths.
        """

class WAeUPLogger(object):

    grok.implements(ILogger)

    _logger = None

    def __init__(self, name, filename=None, site=None, **options):
        self.name = name
        self.filename = filename
        if filename is None:
            if '.' in name:
                name = name.rsplit('.', 1)[1]
            self.filename = "%s.log" % name
        self.site = site
        self.max_bytes = options.get('maxBytes', 5 * 1024 ** 2)
        self.backup_count = options.get('backupCount', 5)
        self.options = options
        return

    @property
    def logger(self):
        if self._needSetup():
            self._setup()
        return logging.getLogger(self._loggername)

    def setup(self):
        return self._setup()

    def update(self, **options):
        self._logger = None # unset to be set up again on next access.
        # XXX: set options
        pass

    def _needSetup(self):
        if self._logger is None:
            return True
        if not '__app' in self._logger.name:
            return False
        if getattr(self.site, '__name__', None) is not None:
            return True
        return False

    def _removeHandlers(self):
        handlers = self._logger.handlers
        for handler in handlers:
            self._logger.removeHandler(handler)

    def _setup(self):
        if self.site is None:
            self.site = grok.getSite()
        self._loggername = self.name
        if not '.' in self._loggername:
            self._loggername = 'waeup.sirp.%s.%s' % ('%s', self._loggername)
        if '%s' in self._loggername:
            site_name = getattr(self.site, '__name__', '__app')
            if site_name is None:
                site_name = '__app'
            self._loggername = self._loggername % (site_name,)
        self._logger = logging.getLogger(self._loggername)
        return self._update()

    def _update(self):
        self._removeHandlers() # Remove any old handlers
        self._logdir = os.path.join(self.site['datacenter'].storage, 'logs')
        if not os.path.exists(self._logdir):
            os.mkdir(self._logdir)
        filename = os.path.join(self._logdir, self.filename)

        # Create a rotating file handler logger for datacenter.
        default_handler = logging.handlers.RotatingFileHandler(
            filename, maxBytes=self.max_bytes, backupCount=self.backup_count)
        self.handler = self.options.get('handler', default_handler)

        default_formatter = logging.Formatter(
            '%(asctime)s - %(levelname)s - %(message)s')
        formatter = self.options.get('formatter', default_formatter)
        self.handler.setFormatter(formatter)

        self._logger.addHandler(self.handler)
        self._logger.propagate = self.options.get('propagate', False)
        self._logger.setLevel(self.options.get('level', logging.DEBUG))
        return self._logger

#: A place where we store seen loggers.
SiteLoggersRepository = dict()

class SiteLoggersFinder(object):
    grok.provides(ISiteLoggers)

    def getLoggers(self, site=None):
        if site is None:
            site = grok.getSite()
        if site not in SiteLoggersRepository.keys():
            SiteLoggersRepository[site] = SiteLoggers()
        return SiteLoggersRepository[site]

grok.global_utility(SiteLoggersFinder, provides=ISiteLoggers)