Python -- Send Email When Exception Is Raised?

Python stdlib has dedicated class to do what you want. See logging.handlers.SMTPHandler

Note: Although this is a simple, obvious solution to the problem as stated, the below answer is probably better in most cases.

If the alternative is this:

if problem_test():
    SendEmail()
    raise Exception

Then why don't you just define a custom raise_email method?

def raise_email(self, e):
    SendEmail()
    raise e

Beware the wizard's apprentice!

It would be better to log those errors, then check to see when the last email was sent, and if the timespan is too short, do not send another message because the human being will already be looking at the log file. For many things, one message per day would be enough, but even for system critical things, if you have already had one failure, what could go wrong if you wait two hours to send the next email?

If you send one email per two hour timespan, then the maximum number of emails per day is 12. And if you get a cascading failure (you will!) then it will most likely happen within a couple of hours of the first failure event.

Most large networking companies offer an SLA of 4 hour to fix a failure, measured from the time it first occurs (because cascading failures tend to repeat) until the customer is satisified that it is fixed. If you have a tighter SLA than that, then unless it is some finance industry service, you probably are offering too high of a service level.

But if you do have a 4 hour SLA, then I would make sure that any email sent within 2 - 4 hours of the last email, should use whatever bells and whistles you can to prioritise it, highlight it, etc. For instance use the X-Priority header and put the word URGENT in the subject so that your mail client can display it in large bold red letters.

like @User said before Python has logging.handlers.SMTPHandler to send logged error message. Use logging module! Overriding exception class to send an email is a bad idea.

Quick example:

import logging
import logging.handlers

smtp_handler = logging.handlers.SMTPHandler(mailhost=("smtp.example.com", 25),
                                            fromaddr="[email protected]", 
                                            toaddrs="[email protected]",
                                            subject=u"AppName error!")


logger = logging.getLogger()
logger.addHandler(smtp_handler)

try:
  break
except Exception as e:
  logger.exception('Unhandled Exception')