+ def __init__(self, init_func_override=None, rcv_func_override=None):
+ self.keep_going = True
+ self.rcv_func = None
+ self.last_ran = time.time()
+
+ # see docs/overview#resiliency for a discussion of this
+ self.instance_send_queue = queue.Queue() # thread safe queue https://docs.python.org/3/library/queue.html
+
+ # intialize rmr context
+ if init_func_override:
+ self.mrc = init_func_override()
+ else:
+ mdc_logger.debug("Waiting for rmr to initialize..")
+ # rmr.RMRFL_MTCALL puts RMR into a multithreaded mode, where a receiving thread populates an
+ # internal ring of messages, and receive calls read from that
+ # currently the size is 2048 messages, so this is fine for the foreseeable future
+ self.mrc = rmr.rmr_init(b"4562", rmr.RMR_MAX_RCV_BYTES, rmr.RMRFL_MTCALL)
+ while rmr.rmr_ready(self.mrc) == 0:
+ time.sleep(0.5)
+
+ # set the receive function
+ self.rcv_func = (
+ rcv_func_override
+ if rcv_func_override
+ else lambda: helpers.rmr_rcvall_msgs_raw(self.mrc, [A1_POLICY_RESPONSE, A1_POLICY_QUERY])
+ )
+
+ # start the work loop
+ self.thread = Thread(target=self.loop)
+ self.thread.start()
+
+ def _assert_good_send(self, sbuf, pre_send_summary):
+ """
+ common helper function for _send_msg and _rts_msg
+ """
+ post_send_summary = rmr.message_summary(sbuf)
+ if post_send_summary["message state"] == 0 and post_send_summary["message status"] == "RMR_OK":
+ return True
+ mdc_logger.debug("Message NOT sent!")
+ mdc_logger.debug("Pre-send summary: {0}, Post-send summary: {1}".format(pre_send_summary, post_send_summary))
+ return False
+
+ def _send_msg(self, pay, mtype, subid):
+ """
+ sends a msg
+ """
+ for _ in range(0, RETRY_TIMES):
+ sbuf = rmr.rmr_alloc_msg(self.mrc, len(pay), payload=pay, gen_transaction_id=True, mtype=mtype, sub_id=subid)
+ sbuf.contents.sub_id = subid
+ pre_send_summary = rmr.message_summary(sbuf)
+ sbuf = rmr.rmr_send_msg(self.mrc, sbuf) # send
+ if self._assert_good_send(sbuf, pre_send_summary):
+ rmr.rmr_free_msg(sbuf) # free
+ break
+
+ def _rts_msg(self, pay, sbuf_rts, mtype):
+ """
+ sends a message using rts
+ we do not call free here because we may rts many times; it is called after the rts loop
+ """
+ for _ in range(0, RETRY_TIMES):
+ pre_send_summary = rmr.message_summary(sbuf_rts)
+ sbuf_rts = rmr.rmr_rts_msg(self.mrc, sbuf_rts, payload=pay, mtype=mtype)
+ if self._assert_good_send(sbuf_rts, pre_send_summary):
+ break
+ return sbuf_rts # in some cases rts may return a new sbuf
+
+ def loop(self):
+ """
+ This loop runs forever, and has 3 jobs:
+ - send out any messages that have to go out (create instance, delete instance)
+ - read a1s mailbox and update the status of all instances based on acks from downstream policy handlers
+ - clean up the database (eg delete the instance) under certain conditions based on those statuses (NOT DONE YET)
+ """
+ # loop forever
+ mdc_logger.debug("Work loop starting")
+ while self.keep_going:
+
+ # send out all messages waiting for us
+ while not self.instance_send_queue.empty():
+ work_item = self.instance_send_queue.get(block=False, timeout=None)
+ payload = json.dumps(messages.a1_to_handler(*work_item)).encode("utf-8")
+ self._send_msg(payload, A1_POLICY_REQUEST, work_item[1])
+
+ # read our mailbox
+ for (msg, sbuf) in self.rcv_func():
+ # TODO: in the future we may also have to catch SDL errors
+ try:
+ mtype = msg["message type"]
+ except (KeyError, TypeError, json.decoder.JSONDecodeError):
+ mdc_logger.debug("Dropping malformed policy ack/query message: {0}".format(msg))
+
+ if mtype == A1_POLICY_RESPONSE:
+ try:
+ # got a policy response, update status
+ pay = json.loads(msg["payload"])
+ data.set_policy_instance_status(
+ pay["policy_type_id"], pay["policy_instance_id"], pay["handler_id"], pay["status"]
+ )
+ mdc_logger.debug("Successfully received status update: {0}".format(pay))
+ except (PolicyTypeNotFound, PolicyInstanceNotFound):
+ mdc_logger.debug("Received a response for a non-existent instance")
+ except (KeyError, TypeError, json.decoder.JSONDecodeError):
+ mdc_logger.debug("Dropping malformed policy ack message: {0}".format(msg))
+
+ elif mtype == A1_POLICY_QUERY:
+ try:
+ # got a query, do a lookup and send out all instances
+ pti = json.loads(msg["payload"])["policy_type_id"]
+ mdc_logger.debug("Received query for: {0}".format(pti))
+ for pii in data.get_instance_list(pti):
+ instance = data.get_policy_instance(pti, pii)
+ payload = json.dumps(messages.a1_to_handler("CREATE", pti, pii, instance)).encode("utf-8")
+ sbuf = self._rts_msg(payload, sbuf, A1_POLICY_REQUEST)
+ except (PolicyTypeNotFound, PolicyInstanceNotFound):
+ mdc_logger.debug("Received a query for a non-existent type: {0}".format(msg))
+ except (KeyError, TypeError, json.decoder.JSONDecodeError):
+ mdc_logger.debug("Dropping malformed policy query message: {0}".format(msg))