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Commit ad0705a0 authored by Jan Rinze Peterzon's avatar Jan Rinze Peterzon
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Task #8571: Refactored Service.py

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LCS/Messaging/python/messaging/Service.py
+ 164
− 177
View file @ ad0705a0
...@@ -29,152 +29,137 @@ import sys ...@@ -29,152 +29,137 @@ import sys
import traceback import traceback
import pickle import pickle
# create service: # create service:
class Service(): class Service:
""" """
Service class for registering python functions with a Service name on a messgage bus. Service class for registering python functions with a Service name on a messgage bus.
""" """
def __init__(self,BusName,ServiceName,ServiceHandler,options=None,exclusive=True,numthreads=1,Verbose=False): def __init__(self, busname, servicename, servicehandler, options=None, exclusive=True, numthreads=1, verbose=False):
self.BusName=BusName self.BusName = busname
self.ServiceName=ServiceName self.ServiceName = servicename
self.ServiceHandler=ServiceHandler self.ServiceHandler = servicehandler
self.connected = False self.connected = False
self.running = False self.running = False
self.exclusive = exclusive self.exclusive = exclusive
self.link_uuid = str(uuid.uuid4()) self.link_uuid = str(uuid.uuid4())
self._numthreads = numthreads self._numthreads = numthreads
self.Verbose=Verbose self.Verbose = verbose
self.options={} self.options = {"capacity": numthreads*20}
self.options["capacity"]=numthreads*20 # Set appropriate flags for exclusive binding
if (self.exclusive==True): if self.exclusive is True:
self.options["link"]="{name:\""+self.link_uuid+"\", x-bindings:[{key:" + self.ServiceName + ", arguments: {\"qpid.exclusive-binding\":True}}]}" self.options["link"] = '{name:"' + self.link_uuid + '", x-bindings:[{key:' + self.ServiceName + ', arguments: {"qpid.exclusive-binding":True}}]}'
if (isinstance(options,dict)): # only add options if it is given as a dictionary
for key,val in options.iter_items(): if isinstance(options,dict):
for key,val in options.iteritems():
self.options[key] = val self.options[key] = val
if (self.BusName!=None): # Usually a service will be listening on a 'bus' implemented by a topic exchange
if self.BusName is not None:
self.Listen = FromBus(self.BusName+"/"+self.ServiceName,options=self.options) self.Listen = FromBus(self.BusName+"/"+self.ServiceName,options=self.options)
self.Reply = ToBus(self.BusName) self.Reply = ToBus(self.BusName)
else: else:
# assume that we are listening on a queue and therefore we cannot use a generic ToBus() for replies.
self.Listen = FromBus(self.ServiceName,options=self.options) self.Listen = FromBus(self.ServiceName,options=self.options)
self.Reply=self.replyto self.Reply=self.replyto
def _debug(self, txt): def _debug(self, txt):
if (self.Verbose==True): if self.Verbose is True:
print(txt) print(txt)
def StartListening(self, numthreads=None): def StartListening(self, numthreads=None):
if (numthreads!=None): if numthreads is not None:
self._numthreads = numthreads self._numthreads = numthreads
self.connected = True self.connected = True
self.running = True self.running = True
self._tr = [] self._tr = []
self.counter=[] self.reccounter = []
self.okcounter =[]
for i in range(self._numthreads): for i in range(self._numthreads):
self._tr.append(threading.Thread(target=self.loop, args=[i])) self._tr.append(threading.Thread(target=self.loop, args=[i]))
self.counter.append(0) self.reccounter.append(0)
self.okcounter.append(0)
self._tr[i].start() self._tr[i].start()
def __enter__(self): def __enter__(self):
if (isinstance(self.Listen,FromBus)): if isinstance(self.Listen,FromBus):
self.Listen.open() self.Listen.open()
if (isinstance(self.Reply,ToBus)): if isinstance(self.Reply,ToBus):
self.Reply.open() self.Reply.open()
return self return self
def __exit__(self, exc_type, exc_val, exc_tb): def __exit__(self, exc_type, exc_val, exc_tb):
self.StopListening() self.StopListening()
def send_reply(self, replymessage, status, reply_to, errtxt="",backtrace=""):
# Compose Reply message from reply and status.
ToSend = ReplyMessage(replymessage, reply_to)
ToSend.status = status
ToSend.errmsg = errtxt
ToSend.backtrace = backtrace
# show the message content if required by the Verbose flag.
if self.Verbose is True:
msg.show()
ToSend.show()
# send the result to the RPC client
if isinstance(self.Reply,ToBus):
self.Reply.send(ToSend)
else:
with ToBus(self.Reply) as dest:
dest.send(ToSend)
def loop(self, index): def loop(self, index):
print( "Thread %d START Listening for messages on Bus %s and service name %s." %(index, self.BusName, self.ServiceName)) print( "Thread %d START Listening for messages on Bus %s and service name %s." %(index, self.BusName, self.ServiceName))
while self.running: while self.running:
msg=None
try: try:
# get the next message # get the next message
msg = self.Listen.receive(1) msg = self.Listen.receive(1)
except Exception as e: # loop until we get a valid message.
print e if msg is None:
continue
# report if messages are not Service Messages
if isinstance(msg, ServiceMessage) is not True:
print "Received wrong messagetype %s, ServiceMessage expected." %(str(type(msg)))
self.Listen.ack(msg)
continue
# Keep track of number of received messages
self.reccounter[index] += 1
try:
if (isinstance(msg,ServiceMessage)):
# Initial status is unknown
status="unknown"
backtrace=None
errtxt=None
#exception=None
# Keep track of number of processed messages
self.counter[index]+=1
replymessage=""
# Execute the service handler function and send reply back to client # Execute the service handler function and send reply back to client
try: try:
self._debug("Running handler") self._debug("Running handler")
replymessage = self.ServiceHandler(msg.content) replymessage = self.ServiceHandler(msg.content)
self._debug("finished handler") self._debug("finished handler")
status="OK" self.send_reply(replymessage,"OK",msg.reply_to)
self._debug(status) self.okcounter[index] += 1
self.Listen.ack(msg)
continue
except Exception as e: except Exception as e:
# Any thrown exceptions either Service exception or unhandled exception # Any thrown exceptions either Service exception or unhandled exception
# during the execution of the service handler is caught here. # during the execution of the service handler is caught here.
self._debug("handling exception") self._debug("handling exception")
exc_info = sys.exc_info() exc_info = sys.exc_info()
backtrace=traceback.format_exception(*exc_info)
errtxt=backtrace[-1]
self._debug(backtrace)
del backtrace[1]
del backtrace[0]
del backtrace[-1]
status="ERROR" status="ERROR"
backtrace= ''.join(backtrace).encode('latin-1').decode('unicode_escape') rawbacktrace = traceback.format_exception(*exc_info)
errtxt = rawbacktrace[-1]
self._debug(rawbacktrace)
# cleanup the backtrace print by removing the first two lines and the last
del rawbacktrace[1]
del rawbacktrace[0]
del rawbacktrace[-1]
backtrace= ''.join(rawbacktrace).encode('latin-1').decode('unicode_escape')
self._debug(backtrace) self._debug(backtrace)
if self.Verbose==True: if self.Verbose is True:
print status print status
print errtxt print errtxt
print backtrace print backtrace
replymessage=None self.send_reply(None,status,msg.reply_to,errtxt=errtxt,backtrace=backtrace)
#exception=pickle.dumps(exc_info)
self._debug("Done call")
# Compose Reply message from reply and status.
ToSend=ReplyMessage(replymessage,msg.reply_to)
ToSend.status=status
if (status!="OK"):
if (errtxt!=None):
ToSend.errmsg=errtxt
else:
ToSend.errmsg=""
if (backtrace!=None):
ToSend.backtrace=backtrace
else:
ToSend.backtrace=""
#if (exception!=None):
# ToSend.exception=exception
#else:
# ToSend.exception=""
# ensure to deliver at the destination in the reply_to field
#ToSend.subject=msg.reply_to
# show the message content if required by the Verbose flag.
if (self.Verbose==True):
msg.show()
ToSend.show()
# send the result to the RPC client
if (isinstance(self.Reply,ToBus)):
self.Reply.send(ToSend)
else:
dest=ToBus(self.Reply)
with dest:
dest.send(ToSend)
# acknowledge the message to the messaging subsystem
self.Listen.ack(msg)
else:
# Report if message wasn't a ServiceMessage.
if (msg!=None):
print "Received wrong messagetype %s, ServiceMessage expected." %(str(type(msg)))
except Exception as e: except Exception as e:
# Unknown problem in the library. Report this and continue. # Unknown problem in the library. Report this and continue.
...@@ -183,20 +168,22 @@ class Service(): ...@@ -183,20 +168,22 @@ class Service():
traceback.print_exception(*excinfo) traceback.print_exception(*excinfo)
print "Thread %d: Resuming listening on bus %s for service %s" %(index,self.BusName,self.ServiceName) print "Thread %d: Resuming listening on bus %s for service %s" %(index,self.BusName,self.ServiceName)
print("Thread %d STOPPED Listening for messages on Bus %s and service name %s and %d processed." %(index,self.BusName,self.ServiceName,self.counter[index])) print("Thread %2d: STOPPED Listening for messages on Bus %s and service name %s." %(index,self.BusName,self.ServiceName))
print(" %d messages received and %d processed OK." %(self.reccounter[index],self.okcounter[index]))
def StopListening(self): def StopListening(self):
# stop all running threads # stop all running threads
if (self.running): if self.running is True:
self.running = False self.running = False
for i in range(self._numthreads): for i in range(self._numthreads):
self._tr[i].join() self._tr[i].join()
# possibly doubly defined.. # possibly doubly defined..
if (self.connected): if self.connected is True:
self.connected = False self.connected = False
if (isinstance(self.Listen,FromBus)): if isinstance(self.Listen, FromBus):
self.Listen.close() self.Listen.close()
if (isinstance(self.Reply,ToBus)): if isinstance(self.Reply, ToBus):
self.Reply.close() self.Reply.close()
def WaitForInterrupt(self): def WaitForInterrupt(self):
...@@ -204,6 +191,6 @@ class Service(): ...@@ -204,6 +191,6 @@ class Service():
while looping: while looping:
try: try:
time.sleep(100) time.sleep(100)
except (KeyboardInterrupt): except KeyboardInterrupt:
looping = False looping = False
print("Keyboard interrupt received.") print("Keyboard interrupt received.")
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