Illustrating a bug (?) in tornado 3.0.1 when fetching a firewalled https url -- a Timeout exception cannot be caught in the calling coroutine.

gistfile1.py

#!/usr/bin/env python3.3

from logging            import getLogger

from tornado.ioloop     import IOLoop
from tornado.options    import parse_command_line
from tornado.httpclient import AsyncHTTPClient
from tornado.httputil   import HTTPHeaders
from tornado.gen        import coroutine


log  = getLogger('tornado.application')
loop = IOLoop.instance()


@coroutine
def fetch_firewalled_url():
    log.info('fetching a badly firewalled url')
    http = AsyncHTTPClient()
    try:
        res = yield http.fetch(
            'https://mtgox.com',
            request_timeout = 5,
            #headers         = HTTPHeaders({'User-Agent':'Mozilla 5.0'})
        )
        err = res.error
    except Exception as exc:
        err = exc

    if err:
        log.error('error has been caught, OK')
        log.error(err)
    else:
        log.info('there was no error, OK')


if __name__ == '__main__':
    parse_command_line()
    loop.run_sync(fetch_firewalled_url)