| """ |
| Framework for python xapps |
| Framework here means Xapp classes that can be subclassed |
| """ |
| # ================================================================================== |
| # Copyright (c) 2020 Nokia |
| # Copyright (c) 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. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| # ================================================================================== |
| from threading import Thread |
| from ricxappframe import xapp_rmr |
| from ricxappframe.xapp_sdl import SDLWrapper |
| from rmr import rmr |
| from mdclogpy import Logger |
| |
| # constants |
| RIC_HEALTH_CHECK_REQ = 100 |
| RIC_HEALTH_CHECK_RESP = 101 |
| |
| |
| # Private base class; not for direct client use |
| |
| |
| class _BaseXapp: |
| """ |
| Base xapp; not for client use directly |
| """ |
| |
| def __init__(self, rmr_port=4562, rmr_wait_for_ready=True, use_fake_sdl=False, post_init=None): |
| """ |
| Init |
| |
| Parameters |
| ---------- |
| rmr_port: int |
| port to listen on |
| |
| rmr_wait_for_ready: bool (optional) |
| if this is True, then init waits until rmr is ready to send, which includes having a valid routing file. |
| this can be set to False if the client only wants to *receive only* |
| |
| use_fake_sdl: bool (optional) |
| if this is True, it uses dbaas' "fake dict backend" instead of Redis or other backends. |
| Set this to true when developing your xapp or during unit testing to completely avoid needing a dbaas running or any network at all |
| |
| post_init: function (optional) |
| runs this user provided function after the base xapp is initialized |
| it's signature should be post_init(self) |
| """ |
| # PUBLIC, can be used by xapps using self.(name): |
| self.logger = Logger(name=__name__) |
| |
| # Start rmr rcv thread |
| self._rmr_loop = xapp_rmr.RmrLoop(port=rmr_port, wait_for_ready=rmr_wait_for_ready) |
| self._mrc = self._rmr_loop.mrc # for convenience |
| |
| # SDL |
| self._sdl = SDLWrapper(use_fake_sdl) |
| |
| # run the optionally provided user post init |
| if post_init: |
| post_init(self) |
| |
| # Public rmr methods |
| |
| def rmr_get_messages(self): |
| """ |
| returns a generator iterable over all current messages in the queue that have not yet been read by the client xapp |
| """ |
| while not self._rmr_loop.rcv_queue.empty(): |
| (summary, sbuf) = self._rmr_loop.rcv_queue.get() |
| yield (summary, sbuf) |
| |
| def rmr_send(self, payload, mtype, retries=100): |
| """ |
| Allocates a buffer, sets payload and mtype, and sends |
| |
| Parameters |
| ---------- |
| payload: bytes |
| payload to set |
| mtype: int |
| message type |
| retries: int (optional) |
| Number of times to retry at the application level before excepting RMRFailure |
| |
| Returns |
| ------- |
| bool |
| whether or not the send worked after retries attempts |
| """ |
| sbuf = rmr.rmr_alloc_msg(vctx=self._mrc, size=len(payload), payload=payload, gen_transaction_id=True, mtype=mtype) |
| |
| for _ in range(retries): |
| sbuf = rmr.rmr_send_msg(self._mrc, sbuf) |
| if sbuf.contents.state == 0: |
| self.rmr_free(sbuf) |
| return True |
| |
| self.rmr_free(sbuf) |
| return False |
| |
| def rmr_rts(self, sbuf, new_payload=None, new_mtype=None, retries=100): |
| """ |
| Allows the xapp to return to sender, possibly adjusting the payload and message type before doing so |
| |
| This does NOT free the sbuf for the caller as the caller may wish to perform multiple rts per buffer. |
| The client needs to free. |
| |
| Parameters |
| ---------- |
| sbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| new_payload: bytes (optional) |
| New payload to set |
| new_mtype: int (optional) |
| New message type (replaces the received message) |
| retries: int (optional) |
| Number of times to retry at the application level before excepting RMRFailure |
| |
| Returns |
| ------- |
| bool |
| whether or not the send worked after retries attempts |
| """ |
| for _ in range(retries): |
| sbuf = rmr.rmr_rts_msg(self._mrc, sbuf, payload=new_payload, mtype=new_mtype) |
| if sbuf.contents.state == 0: |
| return True |
| |
| self.logger.info("RTS Failed! Summary: {}".format(rmr.message_summary(sbuf))) |
| return False |
| |
| def rmr_free(self, sbuf): |
| """ |
| Free an rmr message buffer after use |
| |
| Note: this does not need to be a class method, self is not used. However if we break it out as a function we need a home for it. |
| Parameters |
| ---------- |
| sbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| """ |
| rmr.rmr_free_msg(sbuf) |
| |
| # SDL |
| # NOTE, even though these are passthroughs, the seperate SDL wrapper is useful for other applications like A1. |
| # Therefore, we don't embed that SDLWrapper functionality here so that it can be instantiated on it's own. |
| |
| def sdl_set(self, ns, key, value, usemsgpack=True): |
| """ |
| set a key |
| |
| Parameters |
| ---------- |
| ns: string |
| the sdl namespace |
| key: string |
| the sdl key |
| value: |
| if usemsgpack is True, value can be anything serializable by msgpack |
| if usemsgpack is False, value must be bytes |
| usemsgpack: boolean (optional) |
| determines whether the value is serialized using msgpack |
| """ |
| self._sdl.set(ns, key, value, usemsgpack) |
| |
| def sdl_get(self, ns, key, usemsgpack=True): |
| """ |
| get a key |
| |
| Parameters |
| ---------- |
| ns: string |
| the sdl namespace |
| key: string |
| the sdl key |
| usemsgpack: boolean (optional) |
| if usemsgpack is True, the value is deserialized using msgpack |
| if usemsgpack is False, the value is returned as raw bytes |
| |
| Returns |
| ------- |
| None (if not exist) or see above; depends on usemsgpack |
| """ |
| return self._sdl.get(ns, key, usemsgpack) |
| |
| def sdl_find_and_get(self, ns, prefix, usemsgpack=True): |
| """ |
| get all k v pairs that start with prefix |
| |
| Parameters |
| ---------- |
| ns: string |
| the sdl namespace |
| key: string |
| the sdl key |
| prefix: string |
| the prefix |
| usemsgpack: boolean (optional) |
| if usemsgpack is True, the value returned is a dict where each value has been deserialized using msgpack |
| if usemsgpack is False, the value returned is as a dict mapping keys to raw bytes |
| |
| Returns |
| ------- |
| {} (if no keys match) or see above; depends on usemsgpack |
| """ |
| return self._sdl.find_and_get(ns, prefix, usemsgpack) |
| |
| def sdl_delete(self, ns, key): |
| """ |
| delete a key |
| |
| Parameters |
| ---------- |
| ns: string |
| the sdl namespace |
| key: string |
| the sdl key |
| """ |
| self._sdl.delete(ns, key) |
| |
| # Health |
| |
| def healthcheck(self): |
| """ |
| this needs to be understood how this is supposed to work |
| """ |
| return self._rmr_loop.healthcheck() and self._sdl.healthcheck() |
| |
| def stop(self): |
| """ |
| cleans up and stops the xapp rmr thread (currently) |
| This is critical for unit testing as pytest will never return if the thread is running. |
| |
| TODO: can we register a ctrl-c handler so this gets called on ctrl-c? Because currently two ctrl-c are needed to stop |
| """ |
| self._rmr_loop.stop() |
| |
| |
| # Public Classes to subclass (these subclass _BaseXapp) |
| |
| |
| class RMRXapp(_BaseXapp): |
| """ |
| Represents an xapp that is purely driven by rmr messages (i.e., when messages are received, the xapp does something |
| When run is called, the xapp framework waits for rmr messages, and calls the client provided consume callback on every one |
| """ |
| |
| def __init__(self, default_handler, rmr_port=4562, rmr_wait_for_ready=True, use_fake_sdl=False, post_init=None): |
| """ |
| Parameters |
| ---------- |
| default_handler: function |
| a function with the signature (summary, sbuf) to be called when a message of type message_type is received |
| summary: dict |
| the rmr message summary |
| sbuf: ctypes c_void_p |
| Pointer to an rmr message buffer. The user must call free on this when done. |
| |
| post_init: function (optional) |
| optionally runs this function after the app initializes and before the run loop |
| it's signature should be post_init(self) |
| |
| For the other parameters, see _BaseXapp |
| """ |
| # init base |
| super().__init__( |
| rmr_port=rmr_port, rmr_wait_for_ready=rmr_wait_for_ready, use_fake_sdl=use_fake_sdl, post_init=post_init |
| ) |
| |
| # setup callbacks |
| self._default_handler = default_handler |
| self._dispatch = {} |
| |
| # used for thread control |
| self._keep_going = True |
| |
| # register a default healthcheck handler |
| # this default checks that rmr is working and SDL is working |
| # the user can override this and register their own handler if they wish since the "last registered callback wins". |
| def handle_healthcheck(self, summary, sbuf): |
| ok = self.healthcheck() |
| payload = b"OK\n" if ok else b"ERROR [RMR or SDL is unhealthy]\n" |
| self.rmr_rts(sbuf, new_payload=payload, new_mtype=RIC_HEALTH_CHECK_RESP) |
| self.rmr_free(sbuf) |
| |
| self.register_callback(handle_healthcheck, RIC_HEALTH_CHECK_REQ) |
| |
| def register_callback(self, handler, message_type): |
| """ |
| registers this xapp to call handler(summary, buf) when an rmr message is received of type message_type |
| |
| Parameters |
| ---------- |
| handler: function |
| a function with the signature (summary, sbuf) to be called when a message of type message_type is received |
| summary: dict |
| the rmr message summary |
| sbuf: ctypes c_void_p |
| Pointer to an rmr message buffer. The user must call free on this when done. |
| |
| message:type: int |
| the message type to look for |
| |
| Note if this method is called multiple times for a single message type, the "last one wins". |
| """ |
| self._dispatch[message_type] = handler |
| |
| def run(self, thread=False): |
| """ |
| This function should be called when the client xapp is ready to wait for their handlers to be called on received messages |
| |
| Parameters |
| ---------- |
| thread: bool (optional) |
| if thread is True, execution is returned to caller and the queue read loop is executed in a thread. |
| The thread can be stopped using .stop() |
| if False, execution is not returned and the framework loops |
| """ |
| |
| def loop(): |
| while self._keep_going: |
| if not self._rmr_loop.rcv_queue.empty(): |
| (summary, sbuf) = self._rmr_loop.rcv_queue.get() |
| # dispatch |
| func = self._dispatch.get(summary["message type"], None) |
| if not func: |
| func = self._default_handler |
| func(self, summary, sbuf) |
| |
| if thread: |
| Thread(target=loop).start() |
| else: |
| loop() |
| |
| def stop(self): |
| """ |
| stops the rmr xapp completely. |
| """ |
| super().stop() |
| self.logger.debug("Stopping queue reading thread..") |
| self._keep_going = False |
| |
| |
| class Xapp(_BaseXapp): |
| """ |
| Represents an xapp where the client provides a generic function to call, which is mostly likely a loop-forever loop |
| """ |
| |
| def __init__(self, entrypoint, rmr_port=4562, rmr_wait_for_ready=True, use_fake_sdl=False): |
| """ |
| Parameters |
| ---------- |
| entrypoint: function |
| this function is called when the xapp runs; this is the user code |
| it's signature should be function(self) |
| |
| For the other parameters, see _BaseXapp |
| """ |
| # init base |
| super().__init__(rmr_port=rmr_port, rmr_wait_for_ready=rmr_wait_for_ready, use_fake_sdl=use_fake_sdl) |
| self._entrypoint = entrypoint |
| |
| def run(self): |
| """ |
| This function should be called when the client xapp is ready to start their code |
| """ |
| self._entrypoint(self) |
| |
| # there is no need for stop currently here (base has, and nothing special to do here) |