# API to communicate with a data transfer unit
__version__ = '0.0.1'
import zmq
import socket
import logging
import json
class dataTransfer():
context = None
externalContext = True
signalIp = None
signalPort = None
dataIp = None
hostname = None
dataPort = None
signalSocket = None
dataSocket = None
log = None
supportedConnections = ["priorityStream", "stream", "queryNext", "OnDA", "queryMetadata"]
signalPort_MetadataOnly = "50021"
signalPort_data = "50000"
prioStreamStarted = False
streamStarted = False
queryNextStarted = False
ondaStarted = False
queryMetadataStarted = False
socketResponseTimeout = None
def __init__(self, signalIp, dataPort, dataIp = "0.0.0.0", useLog = False, context = None):
if useLog:
self.log = logging.getLogger("dataTransferAPI")
else:
class loggingFunction:
def out(self, x):
print x
def __init__(self):
self.debug = lambda x: self.out(x)
self.info = lambda x: self.out(x)
self.warning = lambda x: self.out(x)
self.error = lambda x: self.out(x)
self.critical = lambda x: self.out(x)
self.log = loggingFunction()
# ZMQ applications always start by creating a context,
# and then using that for creating sockets
# (source: ZeroMQ, Messaging for Many Applications by Pieter Hintjens)
if context:
self.context = context
self.externalContext = True
else:
self.context = zmq.Context()
self.externalContext = False
self.signalIp = signalIp
self.dataIp = dataIp
self.hostname = socket.gethostname()
self.dataPort = dataPort
self.socketResponseTimeout = 1000
##
#
# Initailizes the signal and data transfer sockets and
# send a signal which the kind of connection to be established
#
# Returns 0 if the connection could be initializes without errors
# Error Codes are:
# 10 if the connection type is not supported
# 11 if there is already one connection running
# 12 Could not send signal
# 13 Could not poll new for new message
# 14 Could not receive answer to signal
# 15 if the response was not correct
#
##
def start(self, connectionType):
if connectionType not in self.supportedConnections:
raise Exception("Chosen type of connection is not supported.")
alreadyConnected = self.streamStarted or self.queryNextStarted or self.ondaStarted or self.queryMetadataStarted or self.prioStreamStarted
signal = None
if connectionType == "priorityStream" and not alreadyConnected:
self.dataSocket = self.context.socket(zmq.PULL)
# An additional socket is needed to establish the data retriving mechanism
connectionStr = "tcp://" + str(self.dataIp) + ":" + str(self.dataPort)
try:
self.dataSocket.bind(connectionStr)
self.log.info("dataSocket started (bind) for '" + connectionStr + "'")
except Exception as e:
self.log.error("Failed to start dataStreamSocket (bind): '" + connectionStr + "'")
self.log.debug("Error was:" + str(e))
self.prioStreamStarted = True
else:
if connectionType == "stream" and not alreadyConnected:
signalPort = self.signalPort_data
signal = "START_LIVE_VIEWER"
elif connectionType == "queryNext" and not alreadyConnected:
signalPort = self.signalPort_data
signal = "START_QUERY_NEWEST"
elif connectionType == "OnDA" and not alreadyConnected:
signalPort = self.signalPort_data
signal = "START_REALTIME_ANALYSIS"
elif connectionType == "queryMetadata" and not alreadyConnected:
signalPort = self.signalPort_MetadataOnly
signal = "START_DISPLAYER"
else:
raise Exception("Other connection type already running.\
More than one connection type is currently not supported.")
self.__creatSignalSocket(signalPort)
message = self.__sendSignal(signal)
if message and message == "NO_VALID_HOST":
self.stop()
raise Exception("Host is not allowed to connect.")
elif message and message == "NO_VALID_SIGNAL":
self.stop()
raise Exception("Connection type is not supported for this kind of sender.")
# if the response was correct
elif message and message.startswith(signal):
self.log.info("Received confirmation ...start receiving files")
if connectionType == "stream":
self.dataSocket = self.context.socket(zmq.PULL)
# An additional socket is needed to establish the data retriving mechanism
connectionStr = "tcp://" + str(self.dataIp) + ":" + str(self.dataPort)
try:
self.dataSocket.bind(connectionStr)
self.log.info("Socket of type " + connectionType + " started (bind) for '" + connectionStr + "'")
except Exception as e:
self.log.error("Failed to start Socket of type " + connectionType + " (bind): '" + connectionStr + "'")
self.log.debug("Error was:" + str(e))
self.streamStarted = True
elif connectionType == "queryNext":
self.dataSocket = self.context.socket(zmq.REQ)
# An additional socket is needed to establish the data retriving mechanism
connectionStr = "tcp://" + str(self.dataIp) + ":" + str(self.dataPort)
try:
self.dataSocket.bind(connectionStr)
self.log.info("Socket of type " + connectionType + " started (bind) for '" + connectionStr + "'")
except Exception as e:
self.log.error("Failed to start Socket of type " + connectionType + " (bind): '" + connectionStr + "'")
self.log.debug("Error was:" + str(e))
self.queryNextStarted = True
elif connectionType == "OnDA":
self.dataSocket = self.context.socket(zmq.REQ)
# An additional socket is needed to establish the data retriving mechanism
connectionStr = "tcp://" + str(self.dataIp) + ":" + str(self.dataPort)
try:
self.dataSocket.connect(connectionStr)
self.log.info("Socket of type " + connectionType + " started (bind) for '" + connectionStr + "'")
except Exception as e:
self.log.error("Failed to start Socket of type " + connectionType + " (bind): '" + connectionStr + "'")
self.log.debug("Error was:" + str(e))
self.ondaStarted = True
elif connectionType == "queryMetadata":
self.dataSocket = self.context.socket(zmq.REQ)
# An additional socket is needed to establish the data retriving mechanism
connectionStr = "tcp://" + str(self.dataIp) + ":" + str(self.dataPort)
try:
self.dataSocket.bind(connectionStr)
self.log.info("Socket of type " + connectionType + " started (bind) for '" + connectionStr + "'")
except Exception as e:
self.log.error("Failed to start Socket of type " + connectionType + " (bind): '" + connectionStr + "'")
self.log.debug("Error was:" + str(e))
self.queryMetadataStarted = True
# if there was no response or the response was of the wrong format, the receiver should be shut down
else:
raise Exception("Sending start signal ...failed.")
return 0
def __creatSignalSocket(self, signalPort):
# To send a notification that a Displayer is up and running, a communication socket is needed
# create socket to exchange signals with Sender
self.signalSocket = self.context.socket(zmq.REQ)
# time to wait for the sender to give a confirmation of the signal
# self.signalSocket.RCVTIMEO = self.socketResponseTimeout
connectionStr = "tcp://" + str(self.signalIp) + ":" + str(signalPort)
try:
self.signalSocket.connect(connectionStr)
self.log.info("signalSocket started (connect) for '" + connectionStr + "'")
except Exception as e:
self.log.error("Failed to start signalSocket (connect): '" + connectionStr + "'")
self.log.debug("Error was:" + str(e))
raise
# using a Poller to implement the signalSocket timeout (in older ZMQ version there is no option RCVTIMEO)
self.poller = zmq.Poller()
self.poller.register(self.signalSocket, zmq.POLLIN)
def __sendSignal(self, signal):
# Send the signal that the communication infrastructure should be established
self.log.info("Sending Signal")
sendMessage = str(signal) + "," + str(self.hostname) + "," + str(self.dataPort) + "," + str(__version__)
self.log.debug("Signal: " + sendMessage)
try:
self.signalSocket.send(sendMessage)
except Exception as e:
self.log.error("Could not send signal")
self.log.info("Error was: " + str(e))
raise
message = None
try:
socks = dict(self.poller.poll(self.socketResponseTimeout))
except Exception as e:
self.log.error("Could not poll for new message")
self.log.info("Error was: " + str(e))
raise
# if there was a response
if self.signalSocket in socks and socks[self.signalSocket] == zmq.POLLIN:
try:
# Get the reply.
message = self.signalSocket.recv()
self.log.info("Received answer to signal: " + str(message) )
except KeyboardInterrupt:
self.log.error("KeyboardInterrupt: No message received")
self.stop()
raise
except Exception as e:
self.log.error("Could not receive answer to signal")
self.log.debug("Error was: " + str(e))
self.stop()
raise
return message
##
#
# Receives or queries for new files depending on the connection initialized
#
# returns either
# the next file
# (if connection type "stream" was choosen)
# the newest file
# (if connection type "queryNext" was choosen)
# the path of the newest file
# (if connection type "queryMetadata" was choosen)
#
##
def get(self):
if self.prioStreamStarted or self.streamStarted:
#run loop, and wait for incoming messages
self.log.debug("Waiting for new messages...")
try:
return self.__getMultipartMessage()
except KeyboardInterrupt:
self.log.debug("Keyboard interrupt detected. Stopping to receive.")
return None
except Exception, e:
self.log.error("Unknown error while receiving files. Need to abort.")
self.log.debug("Error was: " + str(e))
return None
elif self.queryNextStarted or self.ondaStarted or self.queryMetadataStarted:
sendMessage = "NEXT_FILE"
self.log.info("Asking for next file with message " + str(sendMessage))
try:
self.dataSocket.send(sendMessage)
except Exception as e:
self.log.info("Could not send request to dataSocket")
self.log.info("Error was: " + str(e))
return None
try:
# Get the reply.
if self.queryNextStarted or self.ondaStarted:
message = self.dataSocket.recv_multipart()
else:
message = self.dataSocket.recv()
except Exception as e:
message = ""
self.log.info("Could not receive answer to request")
self.log.info("Error was: " + str(e))
return None
return message
else:
self.log.info("Could not communicate, no connection was initialized.")
return None
def __getMultipartMessage(self):
receivingMessages = True
#save all chunks to file
multipartMessage = self.dataSocket.recv_multipart()
#extract multipart message
try:
#TODO is string conversion needed here?
metadata = str(multipartMessage[0])
except:
self.log.error("An empty config was transferred for the multipart-message.")
#TODO validate multipartMessage (like correct dict-values for metadata)
#extraction metadata from multipart-message
try:
metadataDict = json.loads(metadata)
except Exception as e:
self.log.error("Could not extract metadata from the multipart-message.")
self.log.debug("Error was:" + str(e))
try:
payload = multipartMessage[1:]
except Exception as e:
self.log.warning("An empty file was received within the multipart-message")
self.log.debug("Error was:" + str(e))
payload = None
return [metadataDict, payload]
##
#
# Send signal that the displayer is quitting, close ZMQ connections, destoying context
#
##
def stop(self):
if self.dataSocket and not self.prioStreamStarted:
if self.streamStarted:
signal = "STOP_LIVE_VIEWER"
elif self.queryNextStarted:
signal = "STOP_QUERY_NEWEST"
elif self.ondaStarted:
signal = "STOP_REALTIME_ANALYSIS"
elif self.queryMetadataStarted:
signal = "STOP_DISPLAYER"
message = self.__sendSignal(signal)
#TODO need to check correctness of signal?
try:
if self.signalSocket:
self.log.info("closing signalSocket...")
self.signalSocket.close(linger=0)
self.signalSocket = None
if self.dataSocket:
self.log.info("closing dataSocket...")
self.dataSocket.close(linger=0)
self.dataSocket = None
except Exception as e:
self.log.error("closing ZMQ Sockets...failed.")
self.log.info("Error was: " + str(e))
if not self.externalContext:
try:
if self.context:
self.log.info("closing ZMQ context...")
self.context.destroy()
self.context = None
self.log.info("closing ZMQ context...done.")
except Exception as e:
self.log.error("closing ZMQ context...failed.")
self.log.debug("Error was: " + str(e))
self.log.debug(sys.exc_info())
def __exit__(self):
self.stop()
def __del__(self):
self.stop()