| #!/usr/bin/env python3 |
| |
| # Copyright 2019-present Open Networking Foundation |
| # |
| # 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. |
| |
| """ |
| Workflow Probe |
| |
| This module implements Workflow Probe interface |
| """ |
| |
| import json |
| import socketio |
| |
| from .countdown_latch import CountDownLatch |
| from .utils import get_noop_logger, gen_id, gen_seq_id |
| from .errors import ClientRPCError, ClientInputError, ClientResponseError |
| |
| WAIT_TIMEOUT = 10 # 10 seconds |
| |
| GREETING = 'cord.workflow.ctlsvc.greeting' |
| EVENT_EMIT = 'cord.workflow.ctlsvc.event.emit' |
| |
| |
| class Probe(object): |
| def __init__(self, logger=None, name=None): |
| self.sio = socketio.Client() |
| |
| if logger: |
| self.logger = logger |
| else: |
| self.logger = get_noop_logger() |
| |
| if name: |
| self.name = name |
| else: |
| self.name = 'probe_%s' % gen_id() |
| |
| self.req_id = gen_seq_id() |
| |
| # set sio handlers |
| self.logger.debug('Setting event handlers to Socket.IO') |
| self.sio.on('connect', self.__on_sio_connect) |
| self.sio.on('disconnect', self.__on_sio_disconnect) |
| self.sio.on(GREETING, self.__on_greeting_message) |
| self.sio.on(EVENT_EMIT, self.__on_event_emit_message) |
| self.handlers = { |
| 'connect': self.__noop_connect_handler, |
| 'disconnect': self.__noop_disconnect_handler |
| } |
| |
| # key is req_id |
| self.pending_requests = {} |
| |
| def set_logger(self, logger): |
| self.logger = logger |
| |
| def get_logger(self): |
| return self.logger |
| |
| def __on_sio_connect(self): |
| self.logger.debug('connected to the server') |
| handler = self.handlers['connect'] |
| if callable(handler): |
| handler() |
| |
| def __noop_connect_handler(self): |
| self.logger.debug('no-op connect handler') |
| |
| def __on_sio_disconnect(self): |
| self.logger.debug('disconnected from the server') |
| handler = self.handlers['disconnect'] |
| if callable(handler): |
| handler() |
| |
| def __noop_disconnect_handler(self): |
| self.logger.debug('no-op disconnect handler') |
| |
| def __get_next_req_id(self): |
| req_id = self.req_id |
| self.req_id += 1 |
| return req_id |
| |
| def __on_greeting_message(self, data): |
| self.logger.debug('received a greeting message from the server') |
| |
| def __on_event_emit_message(self, data): |
| self.__on_response(EVENT_EMIT, data) |
| |
| def __check_pending_request(self, req_id): |
| """ |
| Check a pending request |
| """ |
| if req_id in self.pending_requests: |
| return True |
| return False |
| |
| def __put_pending_request(self, api, params): |
| """ |
| Put a pending request to a queue |
| """ |
| req_id = self.__get_next_req_id() |
| latch = CountDownLatch() |
| params['req_id'] = req_id # inject req_id |
| self.sio.emit(api, params) |
| self.pending_requests[req_id] = { |
| 'req_id': req_id, |
| 'latch': latch, |
| 'api': api, |
| 'params': params, |
| 'result': None |
| } |
| return req_id |
| |
| def __wait_response(self, req_id): |
| """ |
| Wait for completion of a request |
| """ |
| if req_id in self.pending_requests: |
| req = self.pending_requests[req_id] |
| # python v 3.2 or below does not return a result |
| # that tells whether it is timedout or not |
| return req['latch'].wait(WAIT_TIMEOUT) |
| else: |
| self.logger.error( |
| 'cannot find a pending request (%s) from a queue' % req_id |
| ) |
| raise ClientRPCError( |
| req_id, |
| 'cannot find a pending request (%s) from a queue' % req_id |
| ) |
| |
| def __complete_request(self, req_id, result): |
| """ |
| Compelete a pending request |
| """ |
| if req_id in self.pending_requests: |
| req = self.pending_requests[req_id] |
| req['latch'].count_down() |
| req['result'] = result |
| return |
| |
| self.logger.error( |
| 'cannot find a pending request (%s) from a queue' % req_id |
| ) |
| raise ClientRPCError( |
| req_id, |
| 'cannot find a pending request (%s) from a queue' % req_id |
| ) |
| |
| def __pop_pending_request(self, req_name): |
| """ |
| Pop a pending request from a queue |
| """ |
| return self.pending_requests.pop(req_name, None) |
| |
| def connect(self, url): |
| """ |
| Connect to the given url |
| """ |
| query_string = 'id=%s&type=probe&name=%s' % (self.name, self.name) |
| connect_url = '%s?%s' % (url, query_string) |
| |
| if not (connect_url.startswith('http://') or connect_url.startswith('https://')): |
| connect_url = 'http://%s' % connect_url |
| |
| self.logger.debug('Connecting to a Socket.IO server (%s)' % connect_url) |
| self.sio.connect(url=connect_url, transports=['websocket']) |
| |
| def disconnect(self): |
| """ |
| Disconnect from the server |
| """ |
| self.sio.disconnect() |
| |
| def wait(self): |
| self.sio.wait() |
| |
| def sleep(self, sec): |
| self.sio.sleep(sec) |
| |
| def get_handlers(self): |
| return self.handlers |
| |
| def set_handlers(self, new_handlers): |
| for k in self.handlers: |
| if k in new_handlers: |
| self.handlers[k] = new_handlers[k] |
| |
| def __request(self, api, params={}): |
| if api and params: |
| req_id = self.__put_pending_request(api, params) |
| self.logger.debug('waiting for a response for req_id (%s)' % req_id) |
| self.__wait_response(req_id) # wait for completion |
| req = self.__pop_pending_request(req_id) |
| if req: |
| if req['latch'].get_count() > 0: |
| # timed out |
| self.logger.error('request (%s) timed out' % req_id) |
| raise ClientRPCError( |
| req_id, |
| 'request (%s) timed out' % req_id |
| ) |
| else: |
| return req['result'] |
| else: |
| self.logger.error('cannot find a pending request (%s) from a queue' % req_id) |
| raise ClientRPCError( |
| req_id, |
| 'cannot find a pending request (%s) from a queue' % req_id |
| ) |
| else: |
| self.logger.error( |
| 'invalid arguments api (%s), params (%s)' % |
| (api, json.dumps(params)) |
| ) |
| raise ClientInputError( |
| 'invalid arguments api (%s), params (%s)' % |
| (api, json.dumps(params)) |
| ) |
| |
| def __on_response(self, api, result): |
| if result and 'req_id' in result: |
| self.logger.debug('completing a request (%s)' % result['req_id']) |
| self.__complete_request(result['req_id'], result) |
| else: |
| self.logger.error( |
| 'invalid arguments api (%s), result (%s)' % |
| (api, json.dumps(result)) |
| ) |
| raise ClientInputError( |
| 'invalid arguments api (%s), result (%s)' % |
| (api, json.dumps(result)) |
| ) |
| |
| def emit_event(self, topic, message): |
| """ |
| Emit event to Workflow Controller |
| """ |
| if topic and message: |
| result = self.__request(EVENT_EMIT, { |
| 'topic': topic, |
| 'message': message |
| }) |
| if result['error']: |
| self.logger.error( |
| 'request (%s) failed with an error - %s' % |
| (result['req_id'], result['message']) |
| ) |
| raise ClientResponseError( |
| 'request (%s) failed with an error - %s' % |
| (result['req_id'], result['message']) |
| ) |
| else: |
| return result['result'] |
| else: |
| self.logger.error( |
| 'invalid arguments topic(%s), message(%s)' % |
| (topic, json.dumps(message)) |
| ) |
| raise ClientInputError( |
| 'invalid arguments topic(%s), message(%s)' % |
| (topic, json.dumps(message)) |
| ) |