4 # ==================================================================================
5 # Copyright (c) 2019-2020 Nokia
6 # Copyright (c) 2018-2020 AT&T Intellectual Property.
8 # Licensed under the Apache License, Version 2.0 (the "License");
9 # you may not use this file except in compliance with the License.
10 # You may obtain a copy of the License at
12 # http://www.apache.org/licenses/LICENSE-2.0
14 # Unless required by applicable law or agreed to in writing, software
15 # distributed under the License is distributed on an "AS IS" BASIS,
16 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 # See the License for the specific language governing permissions and
18 # limitations under the License.
19 # ==================================================================================
24 from threading import Thread
25 from ricxappframe.rmr import rmr, helpers
26 from mdclogpy import Logger
27 from a1 import data, messages
28 from a1.exceptions import PolicyTypeNotFound, PolicyInstanceNotFound
30 mdc_logger = Logger(name=__name__)
33 RETRY_TIMES = int(os.environ.get("A1_RMR_RETRY_TIMES", 4))
34 A1_POLICY_REQUEST = 20010
35 A1_POLICY_RESPONSE = 20011
36 A1_POLICY_QUERY = 20012
39 # Note; yes, globals are bad, but this is a private (to this module) global
40 # No other module can import/access this (well, python doesn't enforce this, but all linters will complain)
46 class represents an rmr loop that constantly reads from rmr and performs operations based on waiting messages
47 this launches a thread, it should probably only be called once; the public facing method to access these ensures this
49 TODO: the xapp frame has a version of this looping structure. See if A1 can switch to that.
52 def __init__(self, init_func_override=None, rcv_func_override=None):
53 self.keep_going = True
55 self.last_ran = time.time()
57 # see docs/overview#resiliency for a discussion of this
58 self.instance_send_queue = queue.Queue() # thread safe queue https://docs.python.org/3/library/queue.html
60 # intialize rmr context
61 if init_func_override:
62 self.mrc = init_func_override()
64 mdc_logger.debug("Waiting for rmr to initialize..")
65 # rmr.RMRFL_MTCALL puts RMR into a multithreaded mode, where a receiving thread populates an
66 # internal ring of messages, and receive calls read from that
67 # currently the size is 2048 messages, so this is fine for the foreseeable future
68 self.mrc = rmr.rmr_init(b"4562", rmr.RMR_MAX_RCV_BYTES, rmr.RMRFL_MTCALL)
69 while rmr.rmr_ready(self.mrc) == 0:
72 # set the receive function
76 else lambda: helpers.rmr_rcvall_msgs_raw(self.mrc, [A1_POLICY_RESPONSE, A1_POLICY_QUERY])
80 self.thread = Thread(target=self.loop)
83 def _assert_good_send(self, sbuf, pre_send_summary):
85 common helper function for _send_msg and _rts_msg
87 post_send_summary = rmr.message_summary(sbuf)
88 if post_send_summary["message state"] == 0 and post_send_summary["message status"] == "RMR_OK":
90 mdc_logger.debug("Message NOT sent!")
91 mdc_logger.debug("Pre-send summary: {0}, Post-send summary: {1}".format(pre_send_summary, post_send_summary))
94 def _send_msg(self, pay, mtype, subid):
98 for _ in range(0, RETRY_TIMES):
99 sbuf = rmr.rmr_alloc_msg(self.mrc, len(pay), payload=pay, gen_transaction_id=True, mtype=mtype, sub_id=subid)
100 sbuf.contents.sub_id = subid
101 pre_send_summary = rmr.message_summary(sbuf)
102 mdc_logger.debug("Trying to send message: {}".format(pre_send_summary))
103 sbuf = rmr.rmr_send_msg(self.mrc, sbuf) # send
104 if self._assert_good_send(sbuf, pre_send_summary):
105 rmr.rmr_free_msg(sbuf) # free
108 mdc_logger.debug("A1 did NOT send the message successfully after {} retries!".format(RETRY_TIMES))
110 def _rts_msg(self, pay, sbuf_rts, mtype):
112 sends a message using rts
113 we do not call free here because we may rts many times; it is called after the rts loop
115 for _ in range(0, RETRY_TIMES):
116 pre_send_summary = rmr.message_summary(sbuf_rts)
117 sbuf_rts = rmr.rmr_rts_msg(self.mrc, sbuf_rts, payload=pay, mtype=mtype)
118 if self._assert_good_send(sbuf_rts, pre_send_summary):
120 return sbuf_rts # in some cases rts may return a new sbuf
122 def _handle_sends(self):
123 # send out all messages waiting for us
124 while not self.instance_send_queue.empty():
125 work_item = self.instance_send_queue.get(block=False, timeout=None)
126 payload = json.dumps(messages.a1_to_handler(*work_item)).encode("utf-8")
127 self._send_msg(payload, A1_POLICY_REQUEST, work_item[1])
131 This loop runs forever, and has 3 jobs:
132 - send out any messages that have to go out (create instance, delete instance)
133 - read a1s mailbox and update the status of all instances based on acks from downstream policy handlers
134 - clean up the database (eg delete the instance) under certain conditions based on those statuses (NOT DONE YET)
137 mdc_logger.debug("Work loop starting")
138 while self.keep_going:
141 # We now handle our sends in a thread (that will just exit when it's done) because there is a difference between how send works in SI95 vs NNG.
142 # Send_msg via NNG formerly never blocked.
143 # However under SI95 this send may block for some arbitrary period of time on the first send to an endpoint for which a connection is not established
144 # If this send takes too long, this loop blocks, and the healthcheck will fail, which will cause A1s healthcheck to fail, which will cause Kubernetes to whack A1 and all kinds of horrible things happen.
145 # Therefore, now under SI95, we thread this.
146 Thread(target=self._handle_sends).start()
149 for (msg, sbuf) in self.rcv_func():
150 # TODO: in the future we may also have to catch SDL errors
152 mtype = msg["message type"]
153 except (KeyError, TypeError, json.decoder.JSONDecodeError):
154 mdc_logger.debug("Dropping malformed policy ack/query message: {0}".format(msg))
156 if mtype == A1_POLICY_RESPONSE:
158 # got a policy response, update status
159 pay = json.loads(msg["payload"])
160 data.set_policy_instance_status(
161 pay["policy_type_id"], pay["policy_instance_id"], pay["handler_id"], pay["status"]
163 mdc_logger.debug("Successfully received status update: {0}".format(pay))
164 except (PolicyTypeNotFound, PolicyInstanceNotFound):
165 mdc_logger.debug("Received a response for a non-existent instance")
166 except (KeyError, TypeError, json.decoder.JSONDecodeError):
167 mdc_logger.debug("Dropping malformed policy ack message: {0}".format(msg))
169 elif mtype == A1_POLICY_QUERY:
171 # got a query, do a lookup and send out all instances
172 pti = json.loads(msg["payload"])["policy_type_id"]
173 instance_list = data.get_instance_list(pti) # will raise if a bad type
174 mdc_logger.debug("Received a query for a good type: {0}".format(msg))
175 for pii in instance_list:
176 instance = data.get_policy_instance(pti, pii)
177 payload = json.dumps(messages.a1_to_handler("CREATE", pti, pii, instance)).encode("utf-8")
178 sbuf = self._rts_msg(payload, sbuf, A1_POLICY_REQUEST)
179 except (PolicyTypeNotFound):
180 mdc_logger.debug("Received a query for a non-existent type: {0}".format(msg))
181 except (KeyError, TypeError, json.decoder.JSONDecodeError):
182 mdc_logger.debug("Dropping malformed policy query message: {0}".format(msg))
185 mdc_logger.debug("Received message type {0} but A1 does not handle this".format(mtype))
187 # we must free each sbuf
188 rmr.rmr_free_msg(sbuf)
190 self.last_ran = time.time()
193 mdc_logger.debug("RMR Thread Ending!")
199 def start_rmr_thread(init_func_override=None, rcv_func_override=None):
204 if __RMR_LOOP__ is None:
205 __RMR_LOOP__ = _RmrLoop(init_func_override, rcv_func_override)
208 def stop_rmr_thread():
212 __RMR_LOOP__.keep_going = False
215 def queue_instance_send(item):
217 push an item into the work queue
218 currently the only type of work is to send out messages
220 __RMR_LOOP__.instance_send_queue.put(item)
223 def healthcheck_rmr_thread(seconds=30):
225 returns a boolean representing whether the rmr loop is healthy, by checking two attributes:
227 2. is it stuck in a long (> seconds) loop?
229 return __RMR_LOOP__.thread.is_alive() and ((time.time() - __RMR_LOOP__.last_ran) < seconds)
232 def replace_rcv_func(rcv_func):
233 """purely for the ease of unit testing to test different rcv scenarios"""
234 __RMR_LOOP__.rcv_func = rcv_func