| # |
| # 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. |
| # |
| |
| # pytype: skip-file |
| |
| from apache_beam.io import iobase |
| from apache_beam.transforms.core import Create |
| |
| |
| class _CreateSource(iobase.BoundedSource): |
| """Internal source that is used by Create()""" |
| def __init__(self, serialized_values, coder): |
| self._coder = coder |
| self._serialized_values = [] |
| self._total_size = 0 |
| self._serialized_values = serialized_values |
| self._total_size = sum(map(len, self._serialized_values)) |
| |
| def read(self, range_tracker): |
| start_position = range_tracker.start_position() |
| current_position = start_position |
| |
| def split_points_unclaimed(stop_position): |
| if current_position >= stop_position: |
| return 0 |
| return stop_position - current_position - 1 |
| |
| range_tracker.set_split_points_unclaimed_callback(split_points_unclaimed) |
| element_iter = iter(self._serialized_values[start_position:]) |
| for i in range(start_position, range_tracker.stop_position()): |
| if not range_tracker.try_claim(i): |
| return |
| current_position = i |
| yield self._coder.decode(next(element_iter)) |
| |
| def split(self, desired_bundle_size, start_position=None, stop_position=None): |
| if len(self._serialized_values) < 2: |
| yield iobase.SourceBundle( |
| weight=0, |
| source=self, |
| start_position=0, |
| stop_position=len(self._serialized_values)) |
| else: |
| if start_position is None: |
| start_position = 0 |
| if stop_position is None: |
| stop_position = len(self._serialized_values) |
| avg_size_per_value = self._total_size // len(self._serialized_values) |
| num_values_per_split = max( |
| int(desired_bundle_size // avg_size_per_value), 1) |
| start = start_position |
| while start < stop_position: |
| end = min(start + num_values_per_split, stop_position) |
| remaining = stop_position - end |
| # Avoid having a too small bundle at the end. |
| if remaining < (num_values_per_split // 4): |
| end = stop_position |
| sub_source = Create._create_source( |
| self._serialized_values[start:end], self._coder) |
| yield iobase.SourceBundle( |
| weight=(end - start), |
| source=sub_source, |
| start_position=0, |
| stop_position=(end - start)) |
| start = end |
| |
| def get_range_tracker(self, start_position, stop_position): |
| if start_position is None: |
| start_position = 0 |
| if stop_position is None: |
| stop_position = len(self._serialized_values) |
| from apache_beam import io |
| return io.OffsetRangeTracker(start_position, stop_position) |
| |
| def estimate_size(self): |
| return self._total_size |