AssertionError: Already reading

[ballagas]

I periodically run into this AssertionError when sending mail. The culprit seems to be line 356 in getreply,
line = yield gen.Task(self.sock.read_until, '\n')
but I'm not sure about the proper fix. Posting here for discussion.

[E 141009 17:15:23 ioloop:491] Exception in callback <functools.partial object at 0x7f1460c62c00>
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/tornado/ioloop.py", line 477, in _run_callback
callback()
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 331, in wrapped
raise_exc_info(exc)
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 302, in wrapped
ret = fn(_args, *_kwargs)
File "/usr/local/lib/python2.7/dist-packages/tornado/iostream.py", line 354, in wrapper
callback(_args)
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 331, in wrapped
raise_exc_info(exc)
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 343, in _handle_exception
if tail.exit(_exc):
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 186, in exit
return self.exception_handler(type, value, traceback)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 142, in handle_exception
return runner.handle_exception(typ, value, tb)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 580, in handle_exception
self.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/message.py", line 260, in send
result = yield gen.Task(self.get_connection(fail_silently).send_messages, [self])
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 343, in _handle_exception
if tail.exit(_exc):
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 186, in exit
return self.exception_handler(type, value, traceback)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 142, in handle_exception
return runner.handle_exception(typ, value, tb)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 580, in handle_exception
self.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/backends/smtp.py", line 88, in send_messages
sent = yield gen.Task(self._send, message)
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 343, in _handle_exception
if tail.exit(_exc):
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 186, in exit
return self.exception_handler(type, value, traceback)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 142, in handle_exception
return runner.handle_exception(typ, value, tb)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 580, in handle_exception
self.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/backends/smtp.py", line 107, in _send
email_message.message().as_string())
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 343, in _handle_exception
if tail.exit(_exc):
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 186, in exit
return self.exception_handler(type, value, traceback)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 142, in handle_exception
return runner.handle_exception(typ, value, tb)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 580, in handle_exception
self.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/smtplib.py", line 748, in sendmail
yield gen.Task(self.ehlo_or_helo_if_needed)
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 343, in _handle_exception
if tail.exit(_exc):
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 186, in exit
return self.exception_handler(type, value, traceback)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 142, in handle_exception
return runner.handle_exception(typ, value, tb)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 580, in handle_exception
self.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/smtplib.py", line 552, in ehlo_or_helo_if_needed
result = yield gen.Task(self.ehlo)
File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 302, in wrapped
ret = fn(_args, *_kwargs)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 574, in inner
self.set_result(key, result)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 500, in set_result
self.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/smtplib.py", line 409, in ehlo
result = yield gen.Task(self.getreply)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 557, in run
self.yield_point.start(self)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 377, in start
self.func(_self.args, *_self.kwargs)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 159, in wrapper
runner.run()
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 529, in run
yielded = self.gen.throw(_exc_info)
File "/usr/local/lib/python2.7/dist-packages/tornadomail/smtplib.py", line 356, in getreply
line = yield gen.Task(self.sock.read_until, '\n')
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 557, in run
self.yield_point.start(self)
File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 377, in start
self.func(_self.args, **self.kwargs)
File "/usr/local/lib/python2.7/dist-packages/tornado/iostream.py", line 161, in read_until
self._set_read_callback(callback)
File "/usr/local/lib/python2.7/dist-packages/tornado/iostream.py", line 418, in _set_read_callback
assert not self._read_callback, "Already reading"
AssertionError: Already reading