HDLC Timeout does not take effect

[isidroas]

The default timeout is 10 seconds, but it will wait forever

[isidroas]

Investigation

The pyserial.Serial instance has the timeout attribute set correctly, and is working fine. The problem is that the execution never exits from the following while loop:

# dlms_cosem/io.py:HdlcTransport.next_event
def next_event(self):
        """
        Will read the serial line until a proper response event is read.
        :return:
        """

        while True:
            # If we already have a complete event buffered internally, just
            # return that. Otherwise, read some data, add it to the internal
            # buffer, and then try again.
            event = self.hdlc_connection.next_event()
            if event is state.NEED_DATA:
                self.hdlc_connection.receive_data(self.recv_frame())
                # ^ recv_frame is actually returning empty bytes: b'' after the Serial timeout, but receive_data doesn't do anything with it, and next_event just continues execution indefinitely
                continue
            return event

Investigation done by @markopesevski

[Krolken]

Thanks fort the troubleshooting. The timeout is actually redundant as we now are using compostion of the IO-layer and the transport layer.

Instead this timeout should handle the transport and should be in the next_event method. But we then would want maybe 30 seconds as default so we get a couple of tries on the IO-layer first.

I will look into it.