Message10136

When a call is made from jython (2.7.0) code for connecting to RabbitMQ through pika.BlockingConnection, it results in the following error:

    _socket.error: [Errno 92] Protocol not available


The call to pika.BlockingConnection ends up calling the following block of code in pika
(https://github.com/pika/pika/blob/master/pika/adapters/base_connection.py#L195)


def _create_and_connect_to_socket(self, sock_addr_tuple):
        """Create socket and connect to it, using SSL if enabled.
        :returns: error string on failure; None on success
        """
        self.socket = socket.socket(sock_addr_tuple[0], socket.SOCK_STREAM, 0)


The last value passed in socket.socket(..) denotes the protocol number which is 0 in this case.

This code calls the socket method in jython's _socket.py (https://github.com/jythontools/jython/blob/master/Lib/_socket.py#L1456):


def socket(family=None, type=None, proto=None):
    return _socketobject(family, type, proto)


Since the python code made the call with proto value set to 0, that is the value that will be passed here to _socketobject.


Now, here is the code in _socketobject (https://github.com/jythontools/jython/blob/master/Lib/_socket.py#L1308):


class _socketobject(object):

    __doc__ = _realsocket.__doc__


    def __init__(self, family=AF_INET, type=SOCK_STREAM, proto=0, _sock=None):
        if _sock is None:
            _sock = _realsocket(family, type, proto)


proto still has the value 0 as it gets passed down to realsocket.


class _realsocket(object):

    def __init__(self, family=None, type=None, proto=None):
        # FIXME verify args are correct
        self.family = family
        self.type = type
        if proto is None:
            if type == SOCK_STREAM:
                proto = IPPROTO_TCP
            elif type == SOCK_DGRAM:
                proto = IPPROTO_UDP
        self.proto = proto



Since proto is not None, it does not get assigned the default value of TCP. This zero value eventually causes the "Protocol not available" error.