# Τεκμηρίωση του Django - 1.10.7

# Πηγαίος κώδικας για το django.utils.log

    from __future__ import unicode_literals

    import logging
    import logging.config  # needed when logging_config doesn't start with logging.config
    from copy import copy

    from django.conf import settings
    from django.core import mail
    from django.core.mail import get_connection
    from django.core.management.color import color_style
    from django.utils.module_loading import import_string
    from django.views.debug import ExceptionReporter

    # Default logging for Django. This sends an email to the site admins on every
    # HTTP 500 error. Depending on DEBUG, all other log records are either sent to
    # the console (DEBUG=True) or discarded (DEBUG=False) by means of the
    # require_debug_true filter.
    DEFAULT_LOGGING = {
        'version': 1,
        'disable_existing_loggers': False,
        'filters': {
            'require_debug_false': {
                '()': 'django.utils.log.RequireDebugFalse',
            },
            'require_debug_true': {
                '()': 'django.utils.log.RequireDebugTrue',
            },
        },
        'formatters': {
            'django.server': {
                '()': 'django.utils.log.ServerFormatter',
                'format': '[%(server_time)s] %(message)s',
            }
        },
        'handlers': {
            'console': {
                'level': 'INFO',
                'filters': ['require_debug_true'],
                'class': 'logging.StreamHandler',
            },
            'django.server': {
                'level': 'INFO',
                'class': 'logging.StreamHandler',
                'formatter': 'django.server',
            },
            'mail_admins': {
                'level': 'ERROR',
                'filters': ['require_debug_false'],
                'class': 'django.utils.log.AdminEmailHandler'
            }
        },
        'loggers': {
            'django': {
                'handlers': ['console', 'mail_admins'],
                'level': 'INFO',
            },
            'django.server': {
                'handlers': ['django.server'],
                'level': 'INFO',
                'propagate': False,
            },
        }
    }

    def configure_logging(logging_config, logging_settings):
        if logging_config:
            # First find the logging configuration function ...
            logging_config_func = import_string(logging_config)

            logging.config.dictConfig(DEFAULT_LOGGING)

            # ... then invoke it with the logging settings
            if logging_settings:
                logging_config_func(logging_settings)

    class AdminEmailHandler(logging.Handler):
        """An exception log handler that emails log entries to site admins.

        If the request is passed as the first argument to the log record,
        request data will be provided in the email report.
        """

        def __init__(self, include_html=False, email_backend=None):
            logging.Handler.__init__(self)
            self.include_html = include_html
            self.email_backend = email_backend

        def emit(self, record):
            try:
                request = record.request
                subject = '%s (%s IP): %s' % (
                    record.levelname,
                    ('internal' if request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS
                     else 'EXTERNAL'),
                    record.getMessage()
                )
            except Exception:
                subject = '%s: %s' % (
                    record.levelname,
                    record.getMessage()
                )
                request = None
            subject = self.format_subject(subject)

            # Since we add a nicely formatted traceback on our own, create a copy
            # of the log record without the exception data.
            no_exc_record = copy(record)
            no_exc_record.exc_info = None
            no_exc_record.exc_text = None

            if record.exc_info:
                exc_info = record.exc_info
            else:
                exc_info = (None, record.getMessage(), None)

            reporter = ExceptionReporter(request, is_email=True, *exc_info)
            message = "%s\n\n%s" % (self.format(no_exc_record), reporter.get_traceback_text())
            html_message = reporter.get_traceback_html() if self.include_html else None
            self.send_mail(subject, message, fail_silently=True, html_message=html_message)

        def send_mail(self, subject, message, *args, **kwargs):
            mail.mail_admins(subject, message, *args, connection=self.connection(), **kwargs)

        def connection(self):
            return get_connection(backend=self.email_backend, fail_silently=True)

        def format_subject(self, subject):
            """
            Escape CR and LF characters.
            """
            return subject.replace('\n', '\\n').replace('\r', '\\r')

    class CallbackFilter(logging.Filter):
        """
        A logging filter that checks the return value of a given callable (which
        takes the record-to-be-logged as its only parameter) to decide whether to
        log a record.
        """
        def __init__(self, callback):
            self.callback = callback

        def filter(self, record):
            if self.callback(record):
                return 1
            return 0

    class RequireDebugFalse(logging.Filter):
        def filter(self, record):
            return not settings.DEBUG

    class RequireDebugTrue(logging.Filter):
        def filter(self, record):
            return settings.DEBUG

    class ServerFormatter(logging.Formatter):
        def __init__(self, *args, **kwargs):
            self.style = color_style()
            super(ServerFormatter, self).__init__(*args, **kwargs)

        def format(self, record):
            msg = record.msg
            status_code = getattr(record, 'status_code', None)

            if status_code:
                if 200 <= status_code < 300:
                    # Put 2XX first, since it should be the common case
                    msg = self.style.HTTP_SUCCESS(msg)
                elif 100 <= status_code < 200:
                    msg = self.style.HTTP_INFO(msg)
                elif status_code == 304:
                    msg = self.style.HTTP_NOT_MODIFIED(msg)
                elif 300 <= status_code < 400:
                    msg = self.style.HTTP_REDIRECT(msg)
                elif status_code == 404:
                    msg = self.style.HTTP_NOT_FOUND(msg)
                elif 400 <= status_code < 500:
                    msg = self.style.HTTP_BAD_REQUEST(msg)
                else:
                    # Any 5XX, or any other status code
                    msg = self.style.HTTP_SERVER_ERROR(msg)

            if self.uses_server_time() and not hasattr(record, 'server_time'):
                record.server_time = self.formatTime(record, self.datefmt)

            record.msg = msg
            return super(ServerFormatter, self).format(record)

        def uses_server_time(self):
            return self._fmt.find('%(server_time)') >= 0