def watch(self, interval, handler, evtype=None):
"""
Request to receive notice of subscribe/unsubscribe events for a given
event type.
(Currently there is no option to also select on subscriber.)
Returns a Deferred status value is returned indicating the outcome of the subscribe
operation - StatusVal.SUBSCRIBED indicates a successful outcome.
HACK: for subscription notification events, the subscribed event type is treated as
the source for subscription. This avoids having to keep a separate table for watchers.
"""
Trace("%s watch %us, handler %s to %s"%(self.getUri(), interval, str(handler), evtype),
context="EventLib.EventPubSub")
sts = self.subscribe(interval, handler, evtype=URI.EventSubscribeType, source=evtype)
if sts.syncValue() == StatusVal.SUBSCRIBED:
# Scan existing subscriptions for immediate watch events
Trace("- scanning subscriptions", context="EventLib.EventPubSub")
event = makeEvent(evtype=URI.EventSubscribeType, source=evtype)
for (t,s,h) in self._sub.iterateWild(evtype, None):
Trace("- subscribed (%s,%s,%s)"%(t,s,h), context="EventLib.EventPubSub")
handler.handleEvent(event)
pass
return sts
def watch(self, interval, handler, evtype=None):
"""
Request to receive notice of subscribe/unsubscribe events for a given
event type.
(Currently there is no option to also select on subscriber.)
Returns a Deferred status value is returned indicating the outcome of the subscribe
operation - StatusVal.SUBSCRIBED indicates a successful outcome.
HACK: for subscription notification events, the subscribed event type is treated as
the source for subscription. This avoids having to keep a separate table for watchers.
"""
Trace("%s watch %us, handler %s to %s"%(self.getUri(), interval, str(handler), evtype),
context="EventLib.EventPubSub")
sts = self.subscribe(interval, handler, evtype=URI.EventSubscribeType, source=evtype)
if sts.syncValue() == StatusVal.SUBSCRIBED:
# Scan existing subscriptions for immediate watch events
Trace("- scanning subscriptions", context="EventLib.EventPubSub")
event = makeEvent(evtype=URI.EventSubscribeType, source=evtype)
for (t,s,h) in self._sub.iterateWild(evtype, None):
Trace("- subscribed (%s,%s,%s)"%(t,s,h), context="EventLib.EventPubSub")
handler.handleEvent(event)
pass
return sts
def makeSubscribeEvent(subtype, subscriber, interval, evtype, source):
"""
Return an event object to convey the supplied subscription details.
interval=0 for unsubscribe.
"""
payload = [interval, evtype, source]
return makeEvent(subtype, subscriber, payload)
def makeSubscribeEvent(subtype, subscriber, interval, evtype, source):
"""
Return an event object to convey the supplied subscription details.
interval=0 for unsubscribe.
"""
payload = [interval, evtype, source]
return makeEvent(subtype, subscriber, payload)
def close(self):
"""
Shut down the event router thread
"""
# 'EventCloseType' is a private event type used to shut down the event router,
# which is otherwise ignored.
self._closing = True
self._queue.put( (self.getUri(), makeEvent(evtype=EventCloseType, source=self.getUri())) )
self._thread.join()
return
def close(self):
"""
Shut down the event router thread
"""
# 'EventCloseType' is a private event type used to shut down the event router,
# which is otherwise ignored.
self._closing = True
self._queue.put( (self.getUri(), makeEvent(evtype=EventCloseType, source=self.getUri())) )
self._thread.join()
return
def do_POST(self):
"""
The client is forwarding an event or subscription request:
it needs to be processed for the underlying local event router.
"""
router = self.getRelay()
msgbody = ""
l = int(self.headers.get("content-length", "0"))
if l:
msgbody = self.rfile.read(l)
Info("%s do_POST: '%s'" % (self.getRelay().getUri(), msgbody),
"EventLib.EventRelayHTTPS")
# Parse message and act accordingly
msgdata = parseMessageData(msgbody)
if msgdata == None:
self.send_error(400, "Request body malformed")
return
if msgdata[0] == "forward":
# msgdata = ["forward", [['R1', 'R2', 'R3'], 'ev:typ', 'ev:src', 'payload']]
event = makeEvent(evtype=msgdata[1][1],
source=msgdata[1][2],
payload=msgdata[1][3])
env = constructEnvelope(msgdata[1][0], event)
self.getRelay().forward(event, env)
elif msgdata[0] == "idle":
self.send_response(200, "OK idle")
self.end_headers()
return
elif msgdata[0] == "closedown":
self.send_response(200, "OK closedown")
self.end_headers()
return
else:
self.send_error(400,
"Request body unrecognized option: " + msgdata[0])
return
# Complete request with success response
self.send_response(200, "OK")
self.end_headers()
def do_POST(self):
"""
The client is forwarding an event or subscription request:
it needs to be processed for the underlying local event router.
"""
router = self.getRelay()
msgbody = ""
l = int(self.headers.get("content-length","0"))
if l:
msgbody = self.rfile.read(l)
Info("%s do_POST: '%s'"%(self.getRelay().getUri(),msgbody), "EventLib.EventRelayHTTPS")
# Parse message and act accordingly
msgdata = parseMessageData(msgbody)
if msgdata == None:
self.send_error(400, "Request body malformed")
return
if msgdata[0] == "forward":
# msgdata = ["forward", [['R1', 'R2', 'R3'], 'ev:typ', 'ev:src', 'payload']]
event = makeEvent(evtype=msgdata[1][1],source=msgdata[1][2],payload=msgdata[1][3])
env = constructEnvelope(msgdata[1][0], event)
self.getRelay().forward(event, env)
elif msgdata[0] == "idle":
self.send_response(200, "OK idle")
self.end_headers()
return
elif msgdata[0] == "closedown":
self.send_response(200, "OK closedown")
self.end_headers()
return
else:
self.send_error(400, "Request body unrecognized option: "+msgdata[0])
return
# Complete request with success response
self.send_response(200, "OK")
self.end_headers()
def processEvent(self):
"""
This function is the HTTP client worker thread.
"""
# Note: break out of event dispatch loop when closedown event is received
# and closing flag is set. This is to prevent DoS attack by faked closedown
# event type, and to ensure that prior events received are all processed.
delay_on_error_min = 0.125 # Back off retry interval on error..
delay_on_error_max = 20.0 # ..
delay_on_error = delay_on_error_min # ..
while True:
if delay_on_error < delay_on_error_max:
delay_on_error *= 2
try:
if not self._queue.empty():
Trace("%s queue.get ..." % (self.getUri()),
"EventLib.EventRelayHTTPC")
###msgbody = self._queue.get()
###Trace("%s get msgbody: %s"%(self.getUri(),msgbody), "EventLib.EventRelayHTTPC")
###self._event.set()
msgbody = self.getQueuedItem()
[typ, env] = msgbody
if typ == "closedown":
if self._closing: break
else:
# process request as an HTTP POST request
data = makeEnvelopeData(env)
headers = {
"Content-type": "text/plain",
"Accept": "text/plain",
"Content-length": str(len(data))
}
self._httpcon.request("POST", "/request_path_ignored",
data, headers)
response = self._httpcon.getresponse()
delay_on_error = delay_on_error_min
else:
# Nothing in queue:
# issue a GET for incoming events
Trace("%s HTTP get ..." % (self.getUri()),
"EventLib.EventRelayHTTPC")
headers = {"Accept": "text/plain"}
self._httpcon.request("GET", "/request_path_ignored", None,
headers)
response = self._httpcon.getresponse()
if response.status == 200:
delay_on_error = delay_on_error_min
msgbody = response.read()
Trace("%s get msgbody: %s" % (self.getUri(), msgbody),
"EventLib.EventRelayHTTPC")
# Parse message and act accordingly
msgdata = parseMessageData(msgbody)
Trace(
"%s get msgdata: %s" %
(self.getUri(), str(msgdata)),
"EventLib.EventRelayHTTPC")
if msgdata == None:
#TODO: Log "Request body malformed"
pass
elif msgdata[0] == "forward":
# msgdata = ["forward", [['R1', 'R2', 'R3'], 'ev:typ', 'ev:src', 'payload']]
event = makeEvent(evtype=msgdata[1][1],
source=msgdata[1][2],
payload=msgdata[1][3])
env = constructEnvelope(msgdata[1][0], event)
self.forward(event, env)
elif msgdata[0] == "idle":
# Idle response gives client a chance to send if anything is queued
pass
else:
#TODO: handle closedown message?
Warn(
"%s Request body unrecognized option: %s" %
(self.getUri(), msgdata[0]), "EventRelayHTTPC")
pass
elif response.status == 503:
Trace(
"%s processEvent error response: %u, %s" %
(self.getUri(), response.status, response.reason),
"EventLib.EventRelayHTTPC")
# Remote end closed down
break
else:
# TODO: (log error response)
Warn(
"%s processEvent error response: %u, %s" %
(self.getUri(), response.status, response.reason),
"EventLib.EventRelayHTTPC")
time.sleep(delay_on_error)
except httplib.BadStatusLine, e:
# This can happen at closedown
Info(
"%s processEvent bad response: %s" %
(self.getUri(), str(e)), "EventLib.EventRelayHTTPC")
time.sleep(delay_on_error)
except httplib.CannotSendRequest, e:
# This can happen at closedown
Info("%s Cannot send request: %s" % (self.getUri(), str(e)),
"EventLib.EventRelayHTTPC")
time.sleep(delay_on_error)
def processEvent(self):
"""
This function is the HTTP client worker thread.
"""
# Note: break out of event dispatch loop when closedown event is received
# and closing flag is set. This is to prevent DoS attack by faked closedown
# event type, and to ensure that prior events received are all processed.
delay_on_error_min = 0.125 # Back off retry interval on error..
delay_on_error_max = 20.0 # ..
delay_on_error = delay_on_error_min # ..
while True:
if delay_on_error < delay_on_error_max:
delay_on_error *= 2
try:
# PLEASE NOTE: In the event that the HTTPC is run as duplex, not simplex
# then the post methods will be delayed if nothing is sent down to the client
# from the server. This timeout is controlled by QUEUE_WAIT_TIMEOUT in EventRouterHTTPS.py
if self._simplex == True:
self._queueEvent.wait()
self._queueEvent.clear()
if not self._queue.empty():
Trace("%s queue.get ..."%(self.getUri()), "EventLib.EventRelayHTTPC")
###msgbody = self._queue.get()
###Trace("%s get msgbody: %s"%(self.getUri(),msgbody), "EventLib.EventRelayHTTPC")
###self._event.set()
msgbody = self.getQueuedItem()
[typ,env] = msgbody
if typ == "closedown":
if self._closing: break
else:
# process request as an HTTP POST request
data = makeEnvelopeData(env)
headers = { "Content-type": "text/plain",
"Accept": "text/plain",
"Content-length": str(len(data)) }
self._httpcon.request("POST", "/request_path_ignored", data, headers)
response = self._httpcon.getresponse()
delay_on_error = delay_on_error_min
elif self._simplex == False:
# Nothing in queue:
# issue a GET for incoming events
_log.info("%s HTTP get ..."%(self.getUri()))
headers = { "Accept": "text/plain" }
self._httpcon.request("GET", "/request_path_ignored", None, headers)
response = self._httpcon.getresponse()
if response.status == 200:
delay_on_error = delay_on_error_min
msgbody = response.read()
Trace("%s get msgbody: %s"%(self.getUri(),msgbody), "EventLib.EventRelayHTTPC")
# Parse message and act accordingly
msgdata = parseMessageData(msgbody)
Trace("%s get msgdata: %s"%(self.getUri(),str(msgdata)), "EventLib.EventRelayHTTPC")
if msgdata == None:
#TODO: Log "Request body malformed"
pass
elif msgdata[0] == "forward":
# msgdata = ["forward", [['R1', 'R2', 'R3'], 'ev:typ', 'ev:src', 'payload']]
event = makeEvent(evtype=msgdata[1][1],source=msgdata[1][2],payload=msgdata[1][3])
env = constructEnvelope(msgdata[1][0], event)
self.forward(event, env)
elif msgdata[0] == "idle":
# Idle response gives client a chance to send if anything is queued
pass
else:
#TODO: handle closedown message?
Warn( "%s Request body unrecognized option: %s"%(self.getUri(),msgdata[0]), "EventRelayHTTPC")
pass
elif response.status == 503:
Trace( "%s processEvent error response: %u, %s"%(self.getUri(),response.status,response.reason), "EventLib.EventRelayHTTPC")
# Remote end closed down
break
else:
# TODO: (log error response)
Warn( "%s processEvent error response: %u, %s"%(self.getUri(),response.status,response.reason), "EventLib.EventRelayHTTPC")
time.sleep(delay_on_error)
except httplib.BadStatusLine, e:
# This can happen at closedown
Info( "%s processEvent bad response: %s"%(self.getUri(), str(e)), "EventLib.EventRelayHTTPC")
time.sleep(delay_on_error)
except httplib.CannotSendRequest, e:
# This can happen at closedown
Info( "%s Cannot send request: %s"%(self.getUri(), str(e)), "EventLib.EventRelayHTTPC")
time.sleep(delay_on_error)