def discover_channels(path, serial_number, callback, cancellation_token,
channel_termination_token, logger):
"""
Tries to connect to a UDP server based on the path spec.
This function blocks until cancellation_token is set.
Channels spawned by this function run until channel_termination_token is set.
"""
try:
dest_addr = ':'.join(path.split(":")[:-1])
dest_port = int(path.split(":")[-1])
except (ValueError, IndexError):
raise Exception(
'"{}" is not a valid UDP destination. The format should be something like "localhost:1234".'
.format(path))
while not cancellation_token.is_set():
try:
udp_transport = fibre.udp_transport.UDPTransport(
dest_addr, dest_port, logger)
channel = fibre.protocol.Channel(
"UDP device {}:{}".format(dest_addr, dest_port), udp_transport,
udp_transport, channel_termination_token, logger)
except:
logger.debug("UDP channel init failed. More info: " +
traceback.format_exc())
pass
else:
callback(channel)
wait_any(None, cancellation_token, channel._channel_broken)
time.sleep(1)
def discover_channels(path, serial_number, callback, cancellation_token, channel_termination_token, logger):
"""
Tries to connect to a UDP server based on the path spec.
This function blocks until cancellation_token is set.
Channels spawned by this function run until channel_termination_token is set.
"""
try:
dest_addr = ':'.join(path.split(":")[:-1])
dest_port = int(path.split(":")[-1])
except (ValueError, IndexError):
raise Exception('"{}" is not a valid UDP destination. The format should be something like "localhost:1234".'
.format(path))
while not cancellation_token.is_set():
try:
udp_transport = fibre.udp_transport.UDPTransport(dest_addr, dest_port, logger)
channel = fibre.protocol.Channel(
"UDP device {}:{}".format(dest_addr, dest_port),
udp_transport, udp_transport,
channel_termination_token, logger)
except:
logger.debug("UDP channel init failed. More info: " + traceback.format_exc())
pass
else:
callback(channel)
wait_any(None, cancellation_token, channel._channel_broken)
time.sleep(1)
def remote_endpoint_operation(self, endpoint_id, input, expect_ack,
output_length):
if input is None:
input = bytearray(0)
if (len(input) >= 128):
raise Exception("packet larger than 127 currently not supported")
if (expect_ack):
endpoint_id |= 0x8000
self._my_lock.acquire()
try:
self._outbound_seq_no = ((self._outbound_seq_no + 1) & 0x7fff)
seq_no = self._outbound_seq_no
finally:
self._my_lock.release()
seq_no |= 0x80 # FIXME: we hardwire one bit of the seq-no to 1 to avoid conflicts with the ascii protocol
packet = struct.pack('<HHH', seq_no, endpoint_id, output_length)
packet = packet + input
crc16 = calc_crc16(CRC16_INIT, packet)
if (endpoint_id & 0x7fff == 0):
trailer = PROTOCOL_VERSION
else:
trailer = self._interface_definition_crc
#print("append trailer " + trailer)
packet = packet + struct.pack('<H', trailer)
if (expect_ack):
ack_event = Event()
self._expected_acks[seq_no] = ack_event
try:
attempt = 0
while (attempt < self._send_attempts):
self._my_lock.acquire()
try:
self._output.process_packet(packet)
except ChannelDamagedException:
attempt += 1
continue # resend
finally:
self._my_lock.release()
# Wait for ACK until the resend timeout is exceeded
try:
if wait_any(self._resend_timeout, ack_event,
self._channel_broken) != 0:
raise ChannelBrokenException()
except TimeoutError:
attempt += 1
continue # resend
return self._responses.pop(seq_no)
# TODO: record channel statistics
raise ChannelBrokenException() # Too many resend attempts
finally:
self._expected_acks.pop(seq_no)
self._responses.pop(seq_no, None)
else:
# fire and forget
self._output.process_packet(packet)
return None
def remote_endpoint_operation(self, endpoint_id, input, expect_ack, output_length):
if input is None:
input = bytearray(0)
if (len(input) >= 128):
raise Exception("packet larger than 127 currently not supported")
if (expect_ack):
endpoint_id |= 0x8000
self._my_lock.acquire()
try:
self._outbound_seq_no = ((self._outbound_seq_no + 1) & 0x7fff)
seq_no = self._outbound_seq_no
finally:
self._my_lock.release()
seq_no |= 0x80 # FIXME: we hardwire one bit of the seq-no to 1 to avoid conflicts with the ascii protocol
packet = struct.pack('<HHH', seq_no, endpoint_id, output_length)
packet = packet + input
crc16 = calc_crc16(CRC16_INIT, packet)
if (endpoint_id & 0x7fff == 0):
trailer = PROTOCOL_VERSION
else:
trailer = self._interface_definition_crc
#print("append trailer " + trailer)
packet = packet + struct.pack('<H', trailer)
if (expect_ack):
ack_event = Event()
self._expected_acks[seq_no] = ack_event
try:
attempt = 0
while (attempt < self._send_attempts):
self._my_lock.acquire()
try:
self._output.process_packet(packet)
except ChannelDamagedException:
attempt += 1
continue # resend
except TimeoutError:
attempt += 1
continue # resend
finally:
self._my_lock.release()
# Wait for ACK until the resend timeout is exceeded
try:
if wait_any(self._resend_timeout, ack_event, self._channel_broken) != 0:
raise ChannelBrokenException()
except TimeoutError:
attempt += 1
continue # resend
return self._responses.pop(seq_no)
# TODO: record channel statistics
raise ChannelBrokenException() # Too many resend attempts
finally:
self._expected_acks.pop(seq_no)
self._responses.pop(seq_no, None)
else:
# fire and forget
self._output.process_packet(packet)
return None
