IPInstrument._send() could not send all its data

[nyxus]

I was browsing the instruments code and found out that in the IPInstrument class the socket.send(...) function is implemented wrongly:

    def _send(self, cmd):
        data = cmd + self._terminator
        self._socket.send(data.encode())

This is what the documentation says about socket.send(...):

socket.send(bytes[, flags])
Send data to the socket. The socket must be connected to a remote socket. The optional flags argument has the same meaning as for recv() above. Returns the number of bytes sent. Applications are responsible for checking that all data has been sent; if only some of the data was transmitted, the application needs to attempt delivery of the remaining data.
https://docs.python.org/3.6/library/socket.html

At this moment, if send(...) fails, only a part of the message is transmitted. Which will create strange bugs.

A better solution is to use socket.sendall(...) or as the example shows:

    def mysend(self, msg):
        totalsent = 0
        while totalsent < MSGLEN:
            sent = self.sock.send(msg[totalsent:])
            if sent == 0:
                raise RuntimeError("socket connection broken")
            totalsent = totalsent + sent

https://docs.python.org/3.6/howto/sockets.html#socket-howto

[jenshnielsen]

Thanks for the report. I agree this is obviously wrong. Fixed in #719