stupid.py

#!/usr/bin/env python

from tornado import gen
from tornado.ioloop import IOLoop

from tornado import stack_context

import traceback

def broken(arg1, callback):
    
    def _break():
        print arg1, 'IM GONNA BREAK!'
        raise ValueError()
    
    IOLoop.instance().add_callback(_break)


@gen.coroutine
def exception_is_handled():
    
    print '1before'
    
    try:
        yield gen.Task(broken, '1')
    except:
        print "exception happened. Oh well"
    
    print '1after'
    

@gen.coroutine
def exception_gets_lost():
    
    print '2before'
    
    yield gen.Task(broken, '2')
    
    # never happens
    print '2after'


if __name__ == '__main__':
    
    import logging
    logging.basicConfig()
    
    exception_is_handled()
    exception_gets_lost()
    IOLoop.instance().start()