Source code for apache_beam.transforms.timeutil

#
# 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.
#

"""Timestamp utilities."""

from __future__ import absolute_import

from abc import ABCMeta
from abc import abstractmethod

__all__ = [
    'TimeDomain',
    ]


[docs]class TimeDomain(object): """Time domain for streaming timers.""" WATERMARK = 'WATERMARK' REAL_TIME = 'REAL_TIME' DEPENDENT_REAL_TIME = 'DEPENDENT_REAL_TIME'
[docs] @staticmethod def from_string(domain): if domain in (TimeDomain.WATERMARK, TimeDomain.REAL_TIME, TimeDomain.DEPENDENT_REAL_TIME): return domain raise ValueError('Unknown time domain: %s' % domain)
class TimestampCombinerImpl(object): """Implementation of TimestampCombiner.""" __metaclass__ = ABCMeta @abstractmethod def assign_output_time(self, window, input_timestamp): pass @abstractmethod def combine(self, output_timestamp, other_output_timestamp): pass def combine_all(self, merging_timestamps): """Apply combine to list of timestamps.""" combined_output_time = None for output_time in merging_timestamps: if combined_output_time is None: combined_output_time = output_time else: combined_output_time = self.combine( combined_output_time, output_time) return combined_output_time def merge(self, unused_result_window, merging_timestamps): """Default to returning the result of combine_all.""" return self.combine_all(merging_timestamps) class DependsOnlyOnWindow(TimestampCombinerImpl): """TimestampCombinerImpl that only depends on the window.""" __metaclass__ = ABCMeta def combine(self, output_timestamp, other_output_timestamp): return output_timestamp def merge(self, result_window, unused_merging_timestamps): # Since we know that the result only depends on the window, we can ignore # the given timestamps. return self.assign_output_time(result_window, None) class OutputAtEarliestInputTimestampImpl(TimestampCombinerImpl): """TimestampCombinerImpl outputting at earliest input timestamp.""" def assign_output_time(self, window, input_timestamp): return input_timestamp def combine(self, output_timestamp, other_output_timestamp): """Default to returning the earlier of two timestamps.""" return min(output_timestamp, other_output_timestamp) class OutputAtEarliestTransformedInputTimestampImpl(TimestampCombinerImpl): """TimestampCombinerImpl outputting at earliest input timestamp.""" def __init__(self, window_fn): self.window_fn = window_fn def assign_output_time(self, window, input_timestamp): return self.window_fn.get_transformed_output_time(window, input_timestamp) def combine(self, output_timestamp, other_output_timestamp): return min(output_timestamp, other_output_timestamp) class OutputAtLatestInputTimestampImpl(TimestampCombinerImpl): """TimestampCombinerImpl outputting at latest input timestamp.""" def assign_output_time(self, window, input_timestamp): return input_timestamp def combine(self, output_timestamp, other_output_timestamp): return max(output_timestamp, other_output_timestamp) class OutputAtEndOfWindowImpl(DependsOnlyOnWindow): """TimestampCombinerImpl outputting at end of window.""" def assign_output_time(self, window, unused_input_timestamp): return window.end