As of January 1, 2020 this library no longer supports Python 2 on the latest released version. Library versions released prior to that date will continue to be available. For more information please visit Python 2 support on Google Cloud.

Source code for google.api_core.operation

# Copyright 2016 Google LLC
#
# Licensed 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.

"""Futures for long-running operations returned from Google Cloud APIs.

These futures can be used to synchronously wait for the result of a
long-running operation using :meth:`Operation.result`:


.. code-block:: python

    operation = my_api_client.long_running_method()
    result = operation.result()

Or asynchronously using callbacks and :meth:`Operation.add_done_callback`:

.. code-block:: python

    operation = my_api_client.long_running_method()

    def my_callback(future):
        result = future.result()

    operation.add_done_callback(my_callback)

"""

import functools
import threading

from google.api_core import exceptions
from google.api_core import protobuf_helpers
from google.api_core.future import polling
from google.longrunning import operations_pb2
from google.protobuf import json_format
from google.rpc import code_pb2


[docs]class Operation(polling.PollingFuture): """A Future for interacting with a Google API Long-Running Operation. Args: operation (google.longrunning.operations_pb2.Operation): The initial operation. refresh (Callable[[], ~.api_core.operation.Operation]): A callable that returns the latest state of the operation. cancel (Callable[[], None]): A callable that tries to cancel the operation. result_type (func:`type`): The protobuf type for the operation's result. metadata_type (func:`type`): The protobuf type for the operation's metadata. retry (google.api_core.retry.Retry): The retry configuration used when polling. This can be used to control how often :meth:`done` is polled. Regardless of the retry's ``deadline``, it will be overridden by the ``timeout`` argument to :meth:`result`. """ def __init__( self, operation, refresh, cancel, result_type, metadata_type=None, retry=polling.DEFAULT_RETRY, ): super(Operation, self).__init__(retry=retry) self._operation = operation self._refresh = refresh self._cancel = cancel self._result_type = result_type self._metadata_type = metadata_type self._completion_lock = threading.Lock() # Invoke this in case the operation came back already complete. self._set_result_from_operation() @property def operation(self): """google.longrunning.Operation: The current long-running operation.""" return self._operation @property def metadata(self): """google.protobuf.Message: the current operation metadata.""" if not self._operation.HasField("metadata"): return None return protobuf_helpers.from_any_pb( self._metadata_type, self._operation.metadata )
[docs] @classmethod def deserialize(self, payload): """Deserialize a ``google.longrunning.Operation`` protocol buffer. Args: payload (bytes): A serialized operation protocol buffer. Returns: ~.operations_pb2.Operation: An Operation protobuf object. """ return operations_pb2.Operation.FromString(payload)
def _set_result_from_operation(self): """Set the result or exception from the operation if it is complete.""" # This must be done in a lock to prevent the polling thread # and main thread from both executing the completion logic # at the same time. with self._completion_lock: # If the operation isn't complete or if the result has already been # set, do not call set_result/set_exception again. # Note: self._result_set is set to True in set_result and # set_exception, in case those methods are invoked directly. if not self._operation.done or self._result_set: return if self._operation.HasField("response"): response = protobuf_helpers.from_any_pb( self._result_type, self._operation.response ) self.set_result(response) elif self._operation.HasField("error"): exception = exceptions.from_grpc_status( status_code=self._operation.error.code, message=self._operation.error.message, errors=(self._operation.error,), response=self._operation, ) self.set_exception(exception) else: exception = exceptions.GoogleAPICallError( "Unexpected state: Long-running operation had neither " "response nor error set." ) self.set_exception(exception) def _refresh_and_update(self, retry=polling.DEFAULT_RETRY): """Refresh the operation and update the result if needed. Args: retry (google.api_core.retry.Retry): (Optional) How to retry the RPC. """ # If the currently cached operation is done, no need to make another # RPC as it will not change once done. if not self._operation.done: self._operation = self._refresh(retry=retry) self._set_result_from_operation()
[docs] def done(self, retry=polling.DEFAULT_RETRY): """Checks to see if the operation is complete. Args: retry (google.api_core.retry.Retry): (Optional) How to retry the RPC. Returns: bool: True if the operation is complete, False otherwise. """ self._refresh_and_update(retry) return self._operation.done
[docs] def cancel(self): """Attempt to cancel the operation. Returns: bool: True if the cancel RPC was made, False if the operation is already complete. """ if self.done(): return False self._cancel() return True
[docs] def cancelled(self): """True if the operation was cancelled.""" self._refresh_and_update() return ( self._operation.HasField("error") and self._operation.error.code == code_pb2.CANCELLED )
def _refresh_http(api_request, operation_name, retry=None): """Refresh an operation using a JSON/HTTP client. Args: api_request (Callable): A callable used to make an API request. This should generally be :meth:`google.cloud._http.Connection.api_request`. operation_name (str): The name of the operation. retry (google.api_core.retry.Retry): (Optional) retry policy Returns: google.longrunning.operations_pb2.Operation: The operation. """ path = "operations/{}".format(operation_name) if retry is not None: api_request = retry(api_request) api_response = api_request(method="GET", path=path) return json_format.ParseDict(api_response, operations_pb2.Operation()) def _cancel_http(api_request, operation_name): """Cancel an operation using a JSON/HTTP client. Args: api_request (Callable): A callable used to make an API request. This should generally be :meth:`google.cloud._http.Connection.api_request`. operation_name (str): The name of the operation. """ path = "operations/{}:cancel".format(operation_name) api_request(method="POST", path=path)
[docs]def from_http_json(operation, api_request, result_type, **kwargs): """Create an operation future using a HTTP/JSON client. This interacts with the long-running operations `service`_ (specific to a given API) via `HTTP/JSON`_. .. _HTTP/JSON: https://cloud.google.com/speech/reference/rest/\ v1beta1/operations#Operation Args: operation (dict): Operation as a dictionary. api_request (Callable): A callable used to make an API request. This should generally be :meth:`google.cloud._http.Connection.api_request`. result_type (:func:`type`): The protobuf result type. kwargs: Keyword args passed into the :class:`Operation` constructor. Returns: ~.api_core.operation.Operation: The operation future to track the given operation. """ operation_proto = json_format.ParseDict(operation, operations_pb2.Operation()) refresh = functools.partial(_refresh_http, api_request, operation_proto.name) cancel = functools.partial(_cancel_http, api_request, operation_proto.name) return Operation(operation_proto, refresh, cancel, result_type, **kwargs)
def _refresh_grpc(operations_stub, operation_name, retry=None): """Refresh an operation using a gRPC client. Args: operations_stub (google.longrunning.operations_pb2.OperationsStub): The gRPC operations stub. operation_name (str): The name of the operation. retry (google.api_core.retry.Retry): (Optional) retry policy Returns: google.longrunning.operations_pb2.Operation: The operation. """ request_pb = operations_pb2.GetOperationRequest(name=operation_name) rpc = operations_stub.GetOperation if retry is not None: rpc = retry(rpc) return rpc(request_pb) def _cancel_grpc(operations_stub, operation_name): """Cancel an operation using a gRPC client. Args: operations_stub (google.longrunning.operations_pb2.OperationsStub): The gRPC operations stub. operation_name (str): The name of the operation. """ request_pb = operations_pb2.CancelOperationRequest(name=operation_name) operations_stub.CancelOperation(request_pb)
[docs]def from_grpc(operation, operations_stub, result_type, grpc_metadata=None, **kwargs): """Create an operation future using a gRPC client. This interacts with the long-running operations `service`_ (specific to a given API) via gRPC. .. _service: https://github.com/googleapis/googleapis/blob/\ 050400df0fdb16f63b63e9dee53819044bffc857/\ google/longrunning/operations.proto#L38 Args: operation (google.longrunning.operations_pb2.Operation): The operation. operations_stub (google.longrunning.operations_pb2.OperationsStub): The operations stub. result_type (:func:`type`): The protobuf result type. grpc_metadata (Optional[List[Tuple[str, str]]]): Additional metadata to pass to the rpc. kwargs: Keyword args passed into the :class:`Operation` constructor. Returns: ~.api_core.operation.Operation: The operation future to track the given operation. """ refresh = functools.partial( _refresh_grpc, operations_stub, operation.name, metadata=grpc_metadata ) cancel = functools.partial( _cancel_grpc, operations_stub, operation.name, metadata=grpc_metadata ) return Operation(operation, refresh, cancel, result_type, **kwargs)
[docs]def from_gapic(operation, operations_client, result_type, grpc_metadata=None, **kwargs): """Create an operation future from a gapic client. This interacts with the long-running operations `service`_ (specific to a given API) via a gapic client. .. _service: https://github.com/googleapis/googleapis/blob/\ 050400df0fdb16f63b63e9dee53819044bffc857/\ google/longrunning/operations.proto#L38 Args: operation (google.longrunning.operations_pb2.Operation): The operation. operations_client (google.api_core.operations_v1.OperationsClient): The operations client. result_type (:func:`type`): The protobuf result type. grpc_metadata (Optional[List[Tuple[str, str]]]): Additional metadata to pass to the rpc. kwargs: Keyword args passed into the :class:`Operation` constructor. Returns: ~.api_core.operation.Operation: The operation future to track the given operation. """ refresh = functools.partial( operations_client.get_operation, operation.name, metadata=grpc_metadata ) cancel = functools.partial( operations_client.cancel_operation, operation.name, metadata=grpc_metadata ) return Operation(operation, refresh, cancel, result_type, **kwargs)