I'm developing a flask app in which I'd like to send error level logging to an email address. I tried setting up the typical error handler:
mail_handler = SMTPHandler(mailhost=(app.config['MAIL_SERVER'], app.config['MAIL_PORT']),
fromaddr=app.config['MAIL_FROM_EMAIL'],
toaddrs=['me@my_address.com'],
subject='The server died. That sucks... :(',
credentials=(app.config['MAIL_USERNAME'], app.config['MAIL_PASSWORD']))
Note the configuration values are as set up using flask-mail, with MAIL_USE_SSL=True
and MAIL_PORT=465
.
However, upon invoking an error (on purpose during testing) I get socket timeout errors - other than the port, I can't see how to tell the handler to use SSL. There is a secure=()
parameter that can be passed (see the SMTPHandler docs) but that specifies us of TLS, not SSL.
Any clues how to do this? Thanks!
EDIT - see bottom of post for more up-to-date, code
Figured it out with thanks to Ned Deily pointing out that smtplib (which sits under SMTPHandler) requires special treatment. I also found this post demonstrating how to do that, by overloading the SMTPHandler (in that case to fix a TLS problem).
Using smtplib.SMTP_SSL
(see smtplib docs), rather than the straightforward smtplib.SMTP
, I was able to get the whole system working. This is the utils/logs.py file I use to set up the handlers (which should be a nice example of file, as well as email, handlers):
from your.application.file import app
import smtplib
import logging
from logging.handlers import RotatingFileHandler, SMTPHandler
# Provide a class to allow SSL (Not TLS) connection for mail handlers by overloading the emit() method
class SSLSMTPHandler(SMTPHandler):
def emit(self, record):
"""
Emit a record.
"""
try:
port = self.mailport
if not port:
port = smtplib.SMTP_PORT
smtp = smtplib.SMTP_SSL(self.mailhost, port)
msg = self.format(record)
if self.username:
smtp.login(self.username, self.password)
smtp.sendmail(self.fromaddr, self.toaddrs, msg)
smtp.quit()
except (KeyboardInterrupt, SystemExit):
raise
except:
self.handleError(record)
# Create file handler for error/warning/info/debug logs
file_handler = RotatingFileHandler('logs/app.log', maxBytes=1*1024*1024, backupCount=100)
# Apply format to the log messages
formatter = logging.Formatter("[%(asctime)s] | %(levelname)s | {%(pathname)s:%(lineno)d} | %(message)s")
file_handler.setFormatter(formatter)
# Set the level according to whether we're debugging or not
if app.debug:
file_handler.setLevel(logging.DEBUG)
else:
file_handler.setLevel(logging.WARN)
# Create equivalent mail handler
mail_handler = SSLSMTPHandler(mailhost=(app.config['MAIL_SERVER'], app.config['MAIL_PORT']),
fromaddr=app.config['MAIL_FROM_EMAIL'],
toaddrs='[email protected]',
subject='Your app died. Sad times...',
credentials=(app.config['MAIL_USERNAME'], app.config['MAIL_PASSWORD']))
# Set the email format
mail_handler.setFormatter(logging.Formatter('''
Message type: %(levelname)s
Location: %(pathname)s:%(lineno)d
Module: %(module)s
Function: %(funcName)s
Time: %(asctime)s
Message:
%(message)s
'''))
# Only email errors, not warnings
mail_handler.setLevel(logging.ERROR)
This is registered in my application file with:
# Register the handlers against all the loggers we have in play
# This is done after app configuration and SQLAlchemy initialisation,
# drop the sqlalchemy if not using - I thought a full example would be helpful.
import logging
from .utils.logs import mail_handler, file_handler
loggers = [app.logger, logging.getLogger('sqlalchemy'), logging.getLogger('werkzeug')]
for logger in loggers:
logger.addHandler(file_handler)
# Note - I added a boolean configuration parameter, MAIL_ON_ERROR,
# to allow direct control over whether to email on errors.
# You may wish to use 'if not app.debug' instead.
if app.config['MAIL_ON_ERROR']:
logger.addHandler(mail_handler)
EDIT:
Commenter @EduGord has had trouble emitting the record correctly. Digging deeper, the base SMTPHandler class is sending messages differently than it was 3+ years ago.
This updated emit()
method should get the message to format correctly:
from email.message import EmailMessage
import email.utils
class SSLSMTPHandler(SMTPHandler):
def emit(self, record):
"""
Emit a record.
"""
try:
port = self.mailport
if not port:
port = smtplib.SMTP_PORT
smtp = smtplib.SMTP_SSL(self.mailhost, port)
msg = EmailMessage()
msg['From'] = self.fromaddr
msg['To'] = ','.join(self.toaddrs)
msg['Subject'] = self.getSubject(record)
msg['Date'] = email.utils.localtime()
msg.set_content(self.format(record))
if self.username:
smtp.login(self.username, self.password)
smtp.send_message(msg, self.fromaddr, self.toaddrs)
smtp.quit()
except (KeyboardInterrupt, SystemExit):
raise
except:
self.handleError(record)
Hope this helps somebody!