| # Copyright 2016 Twitter. All rights reserved. |
| # |
| # 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. |
| """module for example spout: WordSpout""" |
| |
| from itertools import cycle |
| from collections import Counter |
| from heronpy.api.spout.spout import Spout |
| from heronpy.api.state.stateful_component import StatefulComponent |
| |
| class StatefulWordSpout(Spout, StatefulComponent): |
| """StatefulWordSpout: emits a set of words repeatedly""" |
| # output field declarer |
| outputs = ['word'] |
| |
| # pylint: disable=attribute-defined-outside-init |
| def init_state(self, stateful_state): |
| self.recovered_state = stateful_state |
| self.logger.info("Checkpoint Snapshot recovered : %s" % str(self.recovered_state)) |
| |
| def pre_save(self, checkpoint_id): |
| # Purely for debugging purposes |
| for (k, v) in self.counter.items(): |
| self.recovered_state.put(k, v) |
| self.logger.info("Checkpoint Snapshot %s : %s" % (checkpoint_id, str(self.recovered_state))) |
| |
| # pylint: disable=unused-argument |
| def initialize(self, config, context): |
| self.logger.info("In initialize() of WordSpout") |
| self.words = cycle(["hello", "bye", "good", "bad", "heron", "storm"]) |
| self.counter = Counter() |
| |
| self.emit_count = 0 |
| self.ack_count = 0 |
| self.fail_count = 0 |
| |
| self.logger.info("Component-specific config: \n%s" % str(config)) |
| |
| def next_tuple(self): |
| word = next(self.words) |
| self.emit([word], tup_id='message id') |
| self.counter[word] += 1 |
| self.emit_count += 1 |
| if self.emit_count % 100000 == 0: |
| self.logger.info("Emitted " + str(self.emit_count)) |
