Source code for apache_beam.runners.pipeline_context

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"""Utility class for serializing pipelines via the runner API.

For internal use only; no backwards-compatibility guarantees.
"""

from __future__ import absolute_import

from builtins import object

from apache_beam import coders
from apache_beam import pipeline
from apache_beam import pvalue
from apache_beam.internal import pickler
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


[docs]class Environment(object): """A wrapper around the environment proto. Provides consistency with how the other componentes are accessed. """ def __init__(self, proto): self._proto = proto
[docs] def to_runner_api(self, context): return self._proto
[docs] @staticmethod def from_runner_api(proto, context): return Environment(proto)
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_proto(self, obj, label=None): return self._id_to_proto[self.get_id(obj, label)] 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, 'environments': Environment, } def __init__( self, proto=None, default_environment=None, use_fake_coders=False): 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))) if default_environment: self._default_environment_id = self.environments.get_id( Environment(default_environment)) else: self._default_environment_id = None self.use_fake_coders = use_fake_coders # If fake coders are requested, return a pickled version of the element type # rather than an actual coder. The element type is required for some runners, # as well as performing a round-trip through protos. # TODO(BEAM-2717): Remove once this is no longer needed.
[docs] def coder_id_from_element_type(self, element_type): if self.use_fake_coders: return pickler.dumps(element_type) else: return self.coders.get_id(coders.registry.get_coder(element_type))
[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
[docs] def default_environment_id(self): return self._default_environment_id