Collate output in Python logging MemoryHandler with SMTPHandler

Question

I have the logging module MemoryHandler set up to queue debug and error messages for the SMTPHandler target. What I want is for an email to be sent when the process errors t

Answer 1

If you are using django - here is simple buffering handler, which will use standard django email methods:

import logging

from django.conf import settings
from django.core.mail import EmailMessage


class DjangoBufferingSMTPHandler(logging.handlers.BufferingHandler):
    def __init__(self, capacity, toaddrs=None, subject=None):
        logging.handlers.BufferingHandler.__init__(self, capacity)

        if toaddrs:
            self.toaddrs = toaddrs
        else:
            # Send messages to site administrators by default
            self.toaddrs = zip(*settings.ADMINS)[-1]

        if subject:
            self.subject = subject
        else:
            self.subject = 'logging'

    def flush(self):
        if len(self.buffer) == 0:
            return

        try:
            msg = "\r\n".join(map(self.format, self.buffer))
            emsg = EmailMessage(self.subject, msg, to=self.toaddrs)
            emsg.send()
        except Exception:
            # handleError() will print exception info to stderr if logging.raiseExceptions is True
            self.handleError(record=None)
        self.buffer = []

In django settings.py you will need to configure email and logging like this:

EMAIL_USE_TLS = True
EMAIL_PORT = 25  
EMAIL_HOST = ''  # example: 'smtp.yandex.ru'
EMAIL_HOST_USER = ''  # example: 'user@yandex.ru'
EMAIL_HOST_PASSWORD = ''
DEFAULT_FROM_EMAIL = EMAIL_HOST_USER
SERVER_EMAIL = EMAIL_HOST_USER

LOGGING = {
    'handlers': {
        ...
        'mail_buffer': {
            'level': 'WARN',
            'capacity': 9999,
            'class': 'utils.logging.DjangoBufferingSMTPHandler',
            # optional: 
            # 'toaddrs': 'admin@host.com'
            # 'subject': 'log messages'
        }
    },
    ...
}