https://github.com/python/cpython/commit/43a6deadbb40bc93e0eaebb3c56c34f8a35... commit: 43a6deadbb40bc93e0eaebb3c56c34f8a3502132 branch: main author: Vinay Sajip <vinay_sajip@yahoo.co.uk> committer: vsajip <vinay_sajip@yahoo.co.uk> date: 2022-08-27T00:24:36+01:00 summary: gh-77116: Add SMTP buffering example to logging cookbook. (GH-96324) files: M Doc/howto/logging-cookbook.rst diff --git a/Doc/howto/logging-cookbook.rst b/Doc/howto/logging-cookbook.rst index 321c4bc510ad..16df3b730ac8 100644 --- a/Doc/howto/logging-cookbook.rst +++ b/Doc/howto/logging-cookbook.rst @@ -2678,6 +2678,88 @@ You can of course use the conventional means of decoration:: ... +.. _buffered-smtp: + +Sending logging messages to email, with buffering +------------------------------------------------- + +To illustrate how you can send log messages via email, so that a set number of +messages are sent per email, you can subclass +:class:`~logging.handlers.BufferingHandler`. In the following example, which you can +adapt to suit your specific needs, a simple test harness is provided which allows you +to run the script with command line arguments specifying what you typically need to +send things via SMTP. (Run the downloaded script with the ``-h`` argument to see the +required and optional arguments.) + +.. code-block:: python + + import logging + import logging.handlers + import smtplib + + class BufferingSMTPHandler(logging.handlers.BufferingHandler): + def __init__(self, mailhost, port, username, password, fromaddr, toaddrs, + subject, capacity): + logging.handlers.BufferingHandler.__init__(self, capacity) + self.mailhost = mailhost + self.mailport = port + self.username = username + self.password = password + self.fromaddr = fromaddr + if isinstance(toaddrs, str): + toaddrs = [toaddrs] + self.toaddrs = toaddrs + self.subject = subject + self.setFormatter(logging.Formatter("%(asctime)s %(levelname)-5s %(message)s")) + + def flush(self): + if len(self.buffer) > 0: + try: + smtp = smtplib.SMTP(self.mailhost, self.mailport) + smtp.starttls() + smtp.login(self.username, self.password) + msg = "From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n" % (self.fromaddr, ','.join(self.toaddrs), self.subject) + for record in self.buffer: + s = self.format(record) + msg = msg + s + "\r\n" + smtp.sendmail(self.fromaddr, self.toaddrs, msg) + smtp.quit() + except Exception: + if logging.raiseExceptions: + raise + self.buffer = [] + + if __name__ == '__main__': + import argparse + + ap = argparse.ArgumentParser() + aa = ap.add_argument + aa('host', metavar='HOST', help='SMTP server') + aa('--port', '-p', type=int, default=587, help='SMTP port') + aa('user', metavar='USER', help='SMTP username') + aa('password', metavar='PASSWORD', help='SMTP password') + aa('to', metavar='TO', help='Addressee for emails') + aa('sender', metavar='SENDER', help='Sender email address') + aa('--subject', '-s', + default='Test Logging email from Python logging module (buffering)', + help='Subject of email') + options = ap.parse_args() + logger = logging.getLogger() + logger.setLevel(logging.DEBUG) + h = BufferingSMTPHandler(options.host, options.port, options.user, + options.password, options.sender, + options.to, options.subject, 10) + logger.addHandler(h) + for i in range(102): + logger.info("Info index = %d", i) + h.flush() + h.close() + +If you run this script and your SMTP server is correctly set up, you should find that +it sends eleven emails to the addressee you specify. The first ten emails will each +have ten log messages, and the eleventh will have two messages. That makes up 102 +messages as specified in the script. + .. _utc-formatting: Formatting times using UTC (GMT) via configuration