X-Git-Url: https://gerrit.o-ran-sc.org/r/gitweb?a=blobdiff_plain;f=a1%2Fa1rmr.py;h=58ec1c06958ac80460805059b904863f54e45321;hb=refs%2Fchanges%2F10%2F2310%2F2;hp=589affdeceb4dae5ea31faebde49cfd2fb89464f;hpb=5ad8f03e1fc7683bb59da31f59edc2f6c0b2372b;p=ric-plt%2Fa1.git diff --git a/a1/a1rmr.py b/a1/a1rmr.py index 589affd..58ec1c0 100644 --- a/a1/a1rmr.py +++ b/a1/a1rmr.py @@ -1,6 +1,9 @@ +""" +a1s rmr functionality +""" # ================================================================================== -# Copyright (c) 2019 Nokia -# Copyright (c) 2018-2019 AT&T Intellectual Property. +# Copyright (c) 2019-2020 Nokia +# Copyright (c) 2018-2020 AT&T Intellectual Property. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. @@ -15,149 +18,200 @@ # limitations under the License. # ================================================================================== import os -import gevent -from rmr import rmr -from a1 import get_module_logger -from a1.exceptions import MessageSendFailure, ExpectedAckNotReceived +import queue +import time +import json +from threading import Thread +from rmr import rmr, helpers +from mdclogpy import Logger +from a1 import data, messages +from a1.exceptions import PolicyTypeNotFound, PolicyInstanceNotFound -logger = get_module_logger(__name__) +mdc_logger = Logger(name=__name__) -RMR_RCV_RETRY_INTERVAL = int(os.environ.get("RMR_RCV_RETRY_INTERVAL", 1000)) -RETRY_TIMES = int(os.environ.get("RMR_RETRY_TIMES", 4)) -MRC = None +RETRY_TIMES = int(os.environ.get("A1_RMR_RETRY_TIMES", 4)) +A1_POLICY_REQUEST = 20010 +A1_POLICY_RESPONSE = 20011 +A1_POLICY_QUERY = 20012 -RECEIVED_MESSAGES = [] # used to store messages we need but havent been procedded yet -WAITING_TRANSIDS = {} # used to store transactionids we are waiting for, so we can filter other stuff out +# Note; yes, globals are bad, but this is a private (to this module) global +# No other module can import/access this (well, python doesn't enforce this, but all linters will complain) +__RMR_LOOP__ = None -def _dequeue_all_waiting_messages(): +class _RmrLoop: """ - dequeue all waiting rmr messages from rmr, put them into RECEIVED_MESSAGES + class represents an rmr loop that constantly reads from rmr and performs operations based on waiting messages + this launches a thread, it should probably only be called once; the public facing method to access these ensures this """ - new_messages = [] - sbuf = rmr.rmr_alloc_msg(MRC, 4096) - while True: - sbuf = rmr.rmr_torcv_msg(MRC, sbuf, 0) # set the timeout to 0 so this doesn't block!! - summary = rmr.message_summary(sbuf) - if summary["message state"] == 12 and summary["message status"] == "RMR_ERR_TIMEOUT": - break - elif summary["transaction id"] in WAITING_TRANSIDS: # message is relevent - new_messages.append(summary) - else: - logger.debug("A message was received by a1, but a1 was not expecting it! It's being dropped: %s", summary) - # do nothing with message, effectively dropped - return new_messages + def __init__(self, init_func_override=None, rcv_func_override=None): + self.keep_going = True + self.rcv_func = None + self.last_ran = time.time() -def _check_if_ack_received(target_transid, target_type): - """ - Try to recieve the latest messages, then search the current queue for the target ACK - TODO: probably a slightly more efficient data structure than list. Maybe a dict by message type - However, in the near term, where there are not many xapps under A1, this is fine. Revisit later. - TODO: do we need to deal with duplicate ACKs for the same transaction id? - Is it possible if the downstream xapp uses rmr_rts? Might be harmless to sit in queue.. might slow things + # 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)) + + else: + mdc_logger.debug("Received message type {0} but A1 does not handle this".format(mtype)) + + # we must free each sbuf + rmr.rmr_free_msg(sbuf) + + self.last_ran = time.time() + time.sleep(1) + + +# Public + + +def start_rmr_thread(init_func_override=None, rcv_func_override=None): """ - new_messages = _dequeue_all_waiting_messages() # dequeue all waiting messages - global RECEIVED_MESSAGES # this is ugly, but fine.. we just need an in memory list across the async calls - RECEIVED_MESSAGES += new_messages - for index, summary in enumerate(RECEIVED_MESSAGES): # Search the queue for the target message - if ( - summary["message state"] == 0 - and summary["message status"] == "RMR_OK" - and summary["message type"] == target_type - and summary["transaction id"] == target_transid - ): # Found; delete it from queue - del RECEIVED_MESSAGES[index] - return summary - return None - - -def init_rmr(): - """ - called from run; not called for unit tests + Start a1s rmr thread """ - global MRC - MRC = rmr.rmr_init(b"4562", rmr.RMR_MAX_RCV_BYTES, 0x00) - - while rmr.rmr_ready(MRC) == 0: - gevent.sleep(1) - logger.debug("not yet ready") + global __RMR_LOOP__ + if __RMR_LOOP__ is None: + __RMR_LOOP__ = _RmrLoop(init_func_override, rcv_func_override) -def send(payload, message_type=0): +def stop_rmr_thread(): """ - sends a message up to RETRY_TIMES - If the message is sent successfully, it returns the transactionid - Raises an exception (MessageSendFailure) otherwise + stops the rmr thread """ - # we may be called many times in asyncronous loops, so for now, it is safer not to share buffers. We can investifgate later whether this is really a problem. - sbuf = rmr.rmr_alloc_msg(MRC, 4096) - payload = payload if isinstance(payload, bytes) else payload.encode("utf-8") - - # retry RETRY_TIMES to send the message - tried = 0 - while True: - # setup the send message - rmr.set_payload_and_length(payload, sbuf) - rmr.generate_and_set_transaction_id(sbuf) - sbuf.contents.state = 0 - sbuf.contents.mtype = message_type - pre_send_summary = rmr.message_summary(sbuf) - logger.debug("Pre message send summary: %s", pre_send_summary) - transaction_id = pre_send_summary["transaction id"] # save the transactionid because we need it later - - # send - sbuf = rmr.rmr_send_msg(MRC, sbuf) - post_send_summary = rmr.message_summary(sbuf) - logger.debug("Post message send summary: %s", rmr.message_summary(sbuf)) - - # check success or failure - if post_send_summary["message state"] == 0 and post_send_summary["message status"] == "RMR_OK": - return transaction_id # we are good - if post_send_summary["message state"] == 10 and post_send_summary["message status"] == "RMR_ERR_RETRY": - # in this state, we should retry - if tried == RETRY_TIMES: - # we have tried RETRY_TIMES and we are still not getting a good state, raise an exception and let the caller deal with it - raise MessageSendFailure(str(post_send_summary)) - else: - tried += 1 - else: - # we hit a state where we should not even retry - raise MessageSendFailure(str(post_send_summary)) + __RMR_LOOP__.keep_going = False -def send_ack_retry(payload, expected_ack_message_type, message_type=0): +def queue_instance_send(item): """ - send a message and check for an ACK. - If no ACK is recieved, defer execution for RMR_RCV_RETRY_INTERVAL ms, then check again. - If no ack is received before the timeout (set by _rmr_init), send again and try again up to RETRY_TIMES + push an item into the work queue + currently the only type of work is to send out messages + """ + __RMR_LOOP__.instance_send_queue.put(item) - It is critical here to set the RMR_TIMEOUT to 0 in the rmr_rcv_to function, which causes that function NOT to block. - Instead, if the message isn't there, we give up execution for the interval, which allows the gevent server to process other requests in the meantime. - Amazing props to https://sdiehl.github.io/gevent-tutorial/ - (which also runs this whole server) +def healthcheck_rmr_thread(seconds=30): + """ + returns a boolean representing whether the rmr loop is healthy, by checking two attributes: + 1. is it running?, + 2. is it stuck in a long (> seconds) loop? """ + return __RMR_LOOP__.thread.is_alive() and ((time.time() - __RMR_LOOP__.last_ran) < seconds) - # try to send the msg to the downstream policy handler - expected_transaction_id = send(payload, message_type) - WAITING_TRANSIDS[expected_transaction_id] = 1 - - gevent.sleep(0.01) # wait 10ms before we try the first recieve - for _ in range(0, RETRY_TIMES): - logger.debug("Seeing if return message is fufilled") - summary = _check_if_ack_received(expected_transaction_id, expected_ack_message_type) - if summary: - logger.debug("Target ack Message received!: %s", summary) - logger.debug("current queue size is %d", len(RECEIVED_MESSAGES)) - del WAITING_TRANSIDS[expected_transaction_id] - return summary["payload"] - else: - logger.debug("Deffering execution for %s seconds", str(RMR_RCV_RETRY_INTERVAL / 1000)) - gevent.sleep(RMR_RCV_RETRY_INTERVAL / 1000) - # we still didn't get the ACK we want - raise ExpectedAckNotReceived() +def replace_rcv_func(rcv_func): + """purely for the ease of unit testing to test different rcv scenarios""" + __RMR_LOOP__.rcv_func = rcv_func