-"""
-a1s rmr functionality
-"""
# ==================================================================================
# Copyright (c) 2019-2020 Nokia
# Copyright (c) 2018-2020 AT&T Intellectual Property.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==================================================================================
+"""
+A1 RMR functionality
+"""
import os
import queue
import time
import json
from threading import Thread
-from rmr import rmr, helpers
+from ricxappframe.rmr import rmr, helpers
from mdclogpy import Logger
from a1 import data, messages
from a1.exceptions import PolicyTypeNotFound, PolicyInstanceNotFound
mdc_logger = Logger(name=__name__)
+# With Nanomsg and NNG it was possible for a send attempt to have a "soft"
+# failure which did warrant some retries if the status of the send is RMR_ERR_RETRY.
+# Because of the way NNG worked, it sometimes required many tens of retries,
+# and a retry state happened often for even moderately "verbose" applications.
+# With SI95 there is still a possibility that a retry is necessary, but it is very rare.
RETRY_TIMES = int(os.environ.get("A1_RMR_RETRY_TIMES", 4))
A1_POLICY_REQUEST = 20010
A1_POLICY_RESPONSE = 20011
class _RmrLoop:
"""
- 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
+ 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.
+
+ TODO: the xapp frame has a version of this looping structure. See if A1 can switch to that.
"""
def __init__(self, init_func_override=None, rcv_func_override=None):
+ """
+ Init
+
+ Parameters
+ ----------
+ init_func_override: function (optional)
+ Function that initializes RMR and answers an RMR context.
+ Supply an empty function to skip initializing RMR.
+
+ rcv_func_override: function (optional)
+ Function that receives messages from RMR and answers a list.
+ Supply a trivial function to skip reading from RMR.
+ """
self.keep_going = True
self.rcv_func = None
self.last_ran = time.time()
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
+ # 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:
def _assert_good_send(self, sbuf, pre_send_summary):
"""
- common helper function for _send_msg and _rts_msg
+ Extracts the send result and logs a detailed warning if the send failed.
+ Returns the message state, an integer that indicates the result.
"""
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
+ if post_send_summary[rmr.RMR_MS_MSG_STATE] != rmr.RMR_OK:
+ mdc_logger.warning("RMR send failed; pre-send summary: {0}, post-send summary: {1}".format(pre_send_summary, post_send_summary))
+ return post_send_summary[rmr.RMR_MS_MSG_STATE]
def _send_msg(self, pay, mtype, subid):
"""
- sends a msg
+ Creates and sends a message via RMR's send-message feature with the specified payload
+ using the specified message type and subscription ID.
"""
+ 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)
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
+ mdc_logger.debug("_send_msg: sending: {}".format(pre_send_summary))
+ sbuf = rmr.rmr_send_msg(self.mrc, sbuf)
+ msg_state = self._assert_good_send(sbuf, pre_send_summary)
+ mdc_logger.debug("_send_msg: result message state: {}".format(msg_state))
+ if msg_state != rmr.RMR_ERR_RETRY:
break
+ rmr.rmr_free_msg(sbuf)
+ if msg_state != rmr.RMR_OK:
+ mdc_logger.warning("_send_msg: failed after {} retries".format(RETRY_TIMES))
+
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
+ Sends a message via RMR's return-to-sender feature.
+ This neither allocates nor frees a message buffer because we may rts many times.
+ Returns the message buffer from the RTS function, which may reallocate it.
"""
+ pre_send_summary = rmr.message_summary(sbuf_rts)
for _ in range(0, RETRY_TIMES):
- pre_send_summary = rmr.message_summary(sbuf_rts)
+ mdc_logger.debug("_rts_msg: sending: {}".format(pre_send_summary))
sbuf_rts = rmr.rmr_rts_msg(self.mrc, sbuf_rts, payload=pay, mtype=mtype)
- if self._assert_good_send(sbuf_rts, pre_send_summary):
+ msg_state = self._assert_good_send(sbuf_rts, pre_send_summary)
+ mdc_logger.debug("_rts_msg: result message state: {}".format(msg_state))
+ if msg_state != rmr.RMR_ERR_RETRY:
break
+
+ if msg_state != rmr.RMR_OK:
+ mdc_logger.warning("_rts_msg: failed after {} retries".format(RETRY_TIMES))
return sbuf_rts # in some cases rts may return a new sbuf
+ def _handle_sends(self):
+ # 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])
+
def loop(self):
"""
This loop runs forever, and has 3 jobs:
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])
+ # Update 3/20/2020
+ # 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.
+ # Send_msg via NNG formerly never blocked.
+ # 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
+ # 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.
+ # Therefore, now under SI95, we thread this.
+ Thread(target=self._handle_sends).start()
# 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"]
+ mtype = msg[rmr.RMR_MS_MSG_TYPE]
except (KeyError, TypeError, json.decoder.JSONDecodeError):
- mdc_logger.debug("Dropping malformed policy ack/query message: {0}".format(msg))
+ mdc_logger.warning("Dropping malformed message: {0}".format(msg))
if mtype == A1_POLICY_RESPONSE:
try:
# got a policy response, update status
- pay = json.loads(msg["payload"])
+ pay = json.loads(msg[rmr.RMR_MS_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")
+ mdc_logger.warning("Received a response for a non-existent type/instance: {0}".format(msg))
except (KeyError, TypeError, json.decoder.JSONDecodeError):
- mdc_logger.debug("Dropping malformed policy ack message: {0}".format(msg))
+ mdc_logger.warning("Dropping malformed policy response: {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):
+ pti = json.loads(msg[rmr.RMR_MS_PAYLOAD])["policy_type_id"]
+ instance_list = data.get_instance_list(pti) # will raise if a bad type
+ mdc_logger.debug("Received a query for a known policy type: {0}".format(msg))
+ for pii in instance_list:
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 (PolicyTypeNotFound):
+ mdc_logger.warning("Received a policy 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))
+ mdc_logger.warning("Dropping malformed policy query: {0}".format(msg))
else:
- mdc_logger.debug("Received message type {0} but A1 does not handle this".format(mtype))
+ mdc_logger.warning("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)
+ mdc_logger.debug("RMR Thread Ending!")
+
# Public
def start_rmr_thread(init_func_override=None, rcv_func_override=None):
"""
Start a1s rmr thread
+
+ Parameters
+ ----------
+ init_func_override: function (optional)
+ Function that initializes RMR and answers an RMR context.
+ Supply an empty function to skip initializing RMR.
+
+ rcv_func_override: function (optional)
+ Function that receives messages from RMR and answers a list.
+ Supply a trivial function to skip reading from RMR.
"""
global __RMR_LOOP__
if __RMR_LOOP__ is None:
Code Review / ric-plt / a1.git / blobdiff