python logging.critical() to raise exception and dump stacktrace and die - python-3.x

Question

I'm porting some code from perl (log4perl) and java (slf4j). All is fine except for logging.critical() does not dump stacktrace and die like it does in the other frameworks, need to add a lot of extra code, logger.exception() also only writes error.
Today I do:
try:
errmsg = "--id={} not found on --host={}".format(args.siteid, args.host)
raise GX8Exception(errmsg)
except GX8Exception as e:
log.exception(e)
sys.exit(-1)
This produces:
2018-01-10 10:09:56,814 [ERROR ] root --id=7A4A7845-7559-4F89-B678-8ADFECF5F7C3 not found on --host=welfare-qa
Traceback (most recent call last):
File "./gx8-controller.py", line 85, in <module>
raise GX8Exception(errmsg)
GX8Exception: --id=7A4A7845-7559-4F89-B678-8ADFECF5F7C3 not found on --host=welfare-qa
Is there a way to config pythonmodule logger to do this, or any other framework to do the same:
log.critical("--id={} not found on --host={}".format(args.siteid, args.host))

Answer 1

One approach would be to create a custom Handler that does nothing but pass log messages on to its super and then exit if the log level is high enough:
import logging
class ExitOnExceptionHandler(logging.StreamHandler):
def emit(self, record):
super().emit(record)
if record.levelno in (logging.ERROR, logging.CRITICAL):
raise SystemExit(-1)
logging.basicConfig(handlers=[ExitOnExceptionHandler()], level=logging.DEBUG)
logger = logging.getLogger('MYTHING')
def causeAProblem():
try:
raise ValueError("Oh no!")
except Exception as e:
logger.exception(e)
logger.warning('Going to try something risky...')
causeAProblem()
print("This won't get printed")
Output:
rat#pandion:~$ python test.py
ERROR:root:Oh no!
Traceback (most recent call last):
File "test.py", line 14, in causeAProblem
raise ValueError("Oh no!")
ValueError: Oh no!
rat#pandion:~$ echo $?
255
However, this could cause unexpected behavior for users of your code. It would be much more straightfoward, if you want to log an exception and exit, to simply leave the exception uncaught. If you want to log a traceback and exit wherever the code is currently calling logging.critical, change it to raise an exception instead.

Answer 2

I inherited some code where I could not change the handler class. I resorted to run time patching of the handler which is a variation on the solution by #nathan-vērzemnieks:
import types
def patch_logging_handler(logger):
def custom_emit(self, record):
self.orig_emit(record)
if record.levelno == logging.FATAL:
raise SystemExit(-1)
handler = logger.handlers[0]
setattr(handler, 'orig_emit', handler.emit)
setattr(handler, 'emit', types.MethodType(custom_emit, handler))

Answer 3

Nathans anwser is great! Been looking for this for a long time,
will just add that you can also do:
if record.levelno >= logging.ERROR:
instead of
if record.levelno in (logging.ERROR, logging.CRITICAL):
to set the minimum level that would cause an exit.