| #!/usr/bin/env python |
| # -*- encoding: utf-8 -*- |
| |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you 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 supplier spout: SupplierSpout""" |
| from heronpy.api.state.stateful_component import StatefulComponent |
| from heronpy.api.spout.spout import Spout |
| |
| from heronpy.streamlet.streamlet import Streamlet |
| from heronpy.streamlet.impl.streamletspoutbase import StreamletSpoutBase |
| |
| # pylint: disable=unused-argument |
| class SupplierSpout(Spout, StatefulComponent, StreamletSpoutBase): |
| """SupplierSpout""" |
| FUNCTION = 'function' |
| |
| def init_state(self, stateful_state): |
| # Supplier does not have any state |
| pass |
| |
| def pre_save(self, checkpoint_id): |
| # Supplier does not have any state |
| pass |
| |
| def initialize(self, config, context): |
| self.logger.debug("SupplierSpout's Component-specific config: \n%s" % str(config)) |
| self.emitted = 0 |
| if SupplierSpout.FUNCTION in config: |
| self._supplier_function = config[SupplierSpout.FUNCTION] |
| else: |
| raise RuntimeError("SupplierSpout needs to be passed supplier function") |
| |
| def next_tuple(self): |
| values = self._supplier_function() |
| self.emit([values], stream='output') |
| self.emitted += 1 |
| |
| # pylint: disable=protected-access |
| class SupplierStreamlet(Streamlet): |
| """SupplierStreamlet""" |
| def __init__(self, supplier_function): |
| super(SupplierStreamlet, self).__init__() |
| if not callable(supplier_function): |
| raise RuntimeError("Supplier function has to be callable") |
| self._supplier_function = supplier_function |
| self.set_num_partitions(1) |
| |
| def _build_this(self, builder, stage_names): |
| if not self.get_name(): |
| self.set_name(self._default_stage_name_calculator("supplier", stage_names)) |
| if self.get_name() in stage_names: |
| raise RuntimeError("Duplicate Names") |
| stage_names.add(self.get_name()) |
| builder.add_spout(self.get_name(), SupplierSpout, par=self.get_num_partitions(), |
| config={SupplierSpout.FUNCTION : self._supplier_function}) |
| return True |