266 lines
8.8 KiB
Python
266 lines
8.8 KiB
Python
# Copyright 2016 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Wrap long-running operations returned from Google Cloud APIs."""
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from google.longrunning import operations_pb2
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from google.protobuf import json_format
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_GOOGLE_APIS_PREFIX = "type.googleapis.com"
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_TYPE_URL_MAP = {}
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def _compute_type_url(klass, prefix=_GOOGLE_APIS_PREFIX):
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"""Compute a type URL for a klass.
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:type klass: type
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:param klass: class to be used as a factory for the given type
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:type prefix: str
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:param prefix: URL prefix for the type
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:rtype: str
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:returns: the URL, prefixed as appropriate
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"""
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name = klass.DESCRIPTOR.full_name
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return "%s/%s" % (prefix, name)
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def register_type(klass, type_url=None):
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"""Register a klass as the factory for a given type URL.
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:type klass: :class:`type`
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:param klass: class to be used as a factory for the given type
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:type type_url: str
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:param type_url: (Optional) URL naming the type. If not provided,
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infers the URL from the type descriptor.
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:raises ValueError: if a registration already exists for the URL.
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"""
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if type_url is None:
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type_url = _compute_type_url(klass)
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if type_url in _TYPE_URL_MAP:
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if _TYPE_URL_MAP[type_url] is not klass:
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raise ValueError("Conflict: %s" % (_TYPE_URL_MAP[type_url],))
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_TYPE_URL_MAP[type_url] = klass
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def _from_any(any_pb):
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"""Convert an ``Any`` protobuf into the actual class.
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Uses the type URL to do the conversion.
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.. note::
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This assumes that the type URL is already registered.
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:type any_pb: :class:`google.protobuf.any_pb2.Any`
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:param any_pb: An any object to be converted.
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:rtype: object
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:returns: The instance (of the correct type) stored in the any
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instance.
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"""
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klass = _TYPE_URL_MAP[any_pb.type_url]
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return klass.FromString(any_pb.value)
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class Operation(object):
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"""Representation of a Google API Long-Running Operation.
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.. _protobuf: https://github.com/googleapis/googleapis/blob/\
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050400df0fdb16f63b63e9dee53819044bffc857/\
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google/longrunning/operations.proto#L80
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.. _service: https://github.com/googleapis/googleapis/blob/\
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050400df0fdb16f63b63e9dee53819044bffc857/\
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google/longrunning/operations.proto#L38
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.. _JSON: https://cloud.google.com/speech/reference/rest/\
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v1beta1/operations#Operation
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This wraps an operation `protobuf`_ object and attempts to
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interact with the long-running operations `service`_ (specific
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to a given API). (Some services also offer a `JSON`_
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API that maps the same underlying data type.)
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:type name: str
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:param name: The fully-qualified path naming the operation.
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:type client: :class:`~google.cloud.client.Client`
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:param client: The client used to poll for the status of the operation.
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If the operation was created via JSON/HTTP, the client
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must own a :class:`~google.cloud._http.Connection`
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to send polling requests. If created via protobuf, the
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client must have a gRPC stub in the ``_operations_stub``
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attribute.
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:type caller_metadata: dict
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:param caller_metadata: caller-assigned metadata about the operation
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"""
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target = None
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"""Instance assocated with the operations: callers may set."""
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response = None
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"""Response returned from completed operation.
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Only one of this and :attr:`error` can be populated.
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"""
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error = None
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"""Error that resulted from a failed (complete) operation.
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Only one of this and :attr:`response` can be populated.
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"""
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metadata = None
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"""Metadata about the current operation (as a protobuf).
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Code that uses operations must register the metadata types (via
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:func:`register_type`) to ensure that the metadata fields can be
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converted into the correct types.
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"""
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_from_grpc = True
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def __init__(self, name, client, **caller_metadata):
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self.name = name
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self.client = client
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self.caller_metadata = caller_metadata.copy()
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self._complete = False
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@classmethod
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def from_pb(cls, operation_pb, client, **caller_metadata):
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"""Factory: construct an instance from a protobuf.
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:type operation_pb:
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:class:`~google.longrunning.operations_pb2.Operation`
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:param operation_pb: Protobuf to be parsed.
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:type client: object: must provide ``_operations_stub`` accessor.
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:param client: The client used to poll for the status of the operation.
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:type caller_metadata: dict
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:param caller_metadata: caller-assigned metadata about the operation
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:rtype: :class:`Operation`
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:returns: new instance, with attributes based on the protobuf.
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"""
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result = cls(operation_pb.name, client, **caller_metadata)
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result._update_state(operation_pb)
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result._from_grpc = True
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return result
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@classmethod
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def from_dict(cls, operation, client, **caller_metadata):
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"""Factory: construct an instance from a dictionary.
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:type operation: dict
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:param operation: Operation as a JSON object.
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:type client: :class:`~google.cloud.client.Client`
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:param client: The client used to poll for the status of the operation.
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:type caller_metadata: dict
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:param caller_metadata: caller-assigned metadata about the operation
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:rtype: :class:`Operation`
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:returns: new instance, with attributes based on the protobuf.
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"""
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operation_pb = json_format.ParseDict(operation, operations_pb2.Operation())
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result = cls(operation_pb.name, client, **caller_metadata)
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result._update_state(operation_pb)
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result._from_grpc = False
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return result
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@property
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def complete(self):
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"""Has the operation already completed?
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:rtype: bool
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:returns: True if already completed, else false.
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"""
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return self._complete
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def _get_operation_rpc(self):
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"""Polls the status of the current operation.
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Uses gRPC request to check.
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:rtype: :class:`~google.longrunning.operations_pb2.Operation`
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:returns: The latest status of the current operation.
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"""
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request_pb = operations_pb2.GetOperationRequest(name=self.name)
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return self.client._operations_stub.GetOperation(request_pb)
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def _get_operation_http(self):
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"""Checks the status of the current operation.
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Uses HTTP request to check.
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:rtype: :class:`~google.longrunning.operations_pb2.Operation`
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:returns: The latest status of the current operation.
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"""
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path = "operations/%s" % (self.name,)
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api_response = self.client._connection.api_request(method="GET", path=path)
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return json_format.ParseDict(api_response, operations_pb2.Operation())
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def _get_operation(self):
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"""Checks the status of the current operation.
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:rtype: :class:`~google.longrunning.operations_pb2.Operation`
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:returns: The latest status of the current operation.
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"""
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if self._from_grpc:
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return self._get_operation_rpc()
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else:
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return self._get_operation_http()
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def _update_state(self, operation_pb):
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"""Update the state of the current object based on operation.
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:type operation_pb:
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:class:`~google.longrunning.operations_pb2.Operation`
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:param operation_pb: Protobuf to be parsed.
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"""
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if operation_pb.done:
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self._complete = True
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if operation_pb.HasField("metadata"):
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self.metadata = _from_any(operation_pb.metadata)
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result_type = operation_pb.WhichOneof("result")
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if result_type == "error":
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self.error = operation_pb.error
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elif result_type == "response":
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self.response = _from_any(operation_pb.response)
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def poll(self):
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"""Check if the operation has finished.
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:rtype: bool
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:returns: A boolean indicating if the current operation has completed.
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:raises ValueError: if the operation
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has already completed.
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"""
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if self.complete:
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raise ValueError("The operation has completed.")
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operation_pb = self._get_operation()
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self._update_state(operation_pb)
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return self.complete
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