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# 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
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"""Utility class for serializing pipelines via the runner API.
For internal use only; no backwards-compatibility guarantees.
"""
from apache_beam import coders
from apache_beam import pipeline
from apache_beam import pvalue
from apache_beam.portability.api import beam_fn_api_pb2
from apache_beam.portability.api import beam_runner_api_pb2
from apache_beam.transforms import core
class _PipelineContextMap(object):
"""This is a bi-directional map between objects and ids.
Under the hood it encodes and decodes these objects into runner API
representations.
"""
def __init__(self, context, obj_type, proto_map=None):
self._pipeline_context = context
self._obj_type = obj_type
self._obj_to_id = {}
self._id_to_obj = {}
self._id_to_proto = dict(proto_map) if proto_map else {}
self._counter = 0
def _unique_ref(self, obj=None, label=None):
self._counter += 1
return "ref_%s_%s_%s" % (
self._obj_type.__name__, label or type(obj).__name__, self._counter)
def populate_map(self, proto_map):
for id, proto in self._id_to_proto.items():
proto_map[id].CopyFrom(proto)
def get_id(self, obj, label=None):
if obj not in self._obj_to_id:
id = self._unique_ref(obj, label)
self._id_to_obj[id] = obj
self._obj_to_id[obj] = id
self._id_to_proto[id] = obj.to_runner_api(self._pipeline_context)
return self._obj_to_id[obj]
def get_by_id(self, id):
if id not in self._id_to_obj:
self._id_to_obj[id] = self._obj_type.from_runner_api(
self._id_to_proto[id], self._pipeline_context)
return self._id_to_obj[id]
def __getitem__(self, id):
return self.get_by_id(id)
def __contains__(self, id):
return id in self._id_to_proto
[docs]class PipelineContext(object):
"""For internal use only; no backwards-compatibility guarantees.
Used for accessing and constructing the referenced objects of a Pipeline.
"""
_COMPONENT_TYPES = {
'transforms': pipeline.AppliedPTransform,
'pcollections': pvalue.PCollection,
'coders': coders.Coder,
'windowing_strategies': core.Windowing,
# TODO: environment
}
def __init__(self, proto=None):
if isinstance(proto, beam_fn_api_pb2.ProcessBundleDescriptor):
proto = beam_runner_api_pb2.Components(
coders=dict(proto.coders.items()),
windowing_strategies=dict(proto.windowing_strategies.items()),
environments=dict(proto.environments.items()))
for name, cls in self._COMPONENT_TYPES.items():
setattr(
self, name, _PipelineContextMap(
self, cls, getattr(proto, name, None)))
[docs] @staticmethod
def from_runner_api(proto):
return PipelineContext(proto)
[docs] def to_runner_api(self):
context_proto = beam_runner_api_pb2.Components()
for name in self._COMPONENT_TYPES:
getattr(self, name).populate_map(getattr(context_proto, name))
return context_proto