379 lines
15 KiB
Python
379 lines
15 KiB
Python
# Copyright 2015 Google Inc. All rights reserved.
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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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"""User friendly container for Google Cloud Bigtable Table."""
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from gcloud._helpers import _to_bytes
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from gcloud.bigtable._generated_v2 import (
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bigtable_pb2 as data_messages_v2_pb2)
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from gcloud.bigtable._generated_v2 import (
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bigtable_table_admin_pb2 as table_admin_messages_v2_pb2)
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from gcloud.bigtable.column_family import _gc_rule_from_pb
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from gcloud.bigtable.column_family import ColumnFamily
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from gcloud.bigtable.row import AppendRow
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from gcloud.bigtable.row import ConditionalRow
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from gcloud.bigtable.row import DirectRow
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from gcloud.bigtable.row_data import PartialRowsData
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class Table(object):
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"""Representation of a Google Cloud Bigtable Table.
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.. note::
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We don't define any properties on a table other than the name. As
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the proto says, in a request:
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The ``name`` field of the Table and all of its ColumnFamilies must
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be left blank, and will be populated in the response.
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This leaves only the ``current_operation`` and ``granularity``
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fields. The ``current_operation`` is only used for responses while
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``granularity`` is an enum with only one value.
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We can use a :class:`Table` to:
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* :meth:`create` the table
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* :meth:`rename` the table
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* :meth:`delete` the table
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* :meth:`list_column_families` in the table
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:type table_id: str
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:param table_id: The ID of the table.
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:type instance: :class:`Cluster <.instance.Instance>`
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:param instance: The instance that owns the table.
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"""
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def __init__(self, table_id, instance):
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self.table_id = table_id
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self._instance = instance
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@property
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def name(self):
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"""Table name used in requests.
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.. note::
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This property will not change if ``table_id`` does not, but the
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return value is not cached.
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The table name is of the form
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``"projects/../zones/../clusters/../tables/{table_id}"``
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:rtype: str
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:returns: The table name.
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"""
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return self._instance.name + '/tables/' + self.table_id
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def column_family(self, column_family_id, gc_rule=None):
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"""Factory to create a column family associated with this table.
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:type column_family_id: str
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:param column_family_id: The ID of the column family. Must be of the
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form ``[_a-zA-Z0-9][-_.a-zA-Z0-9]*``.
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:type gc_rule: :class:`.GarbageCollectionRule`
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:param gc_rule: (Optional) The garbage collection settings for this
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column family.
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:rtype: :class:`.ColumnFamily`
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:returns: A column family owned by this table.
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"""
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return ColumnFamily(column_family_id, self, gc_rule=gc_rule)
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def row(self, row_key, filter_=None, append=False):
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"""Factory to create a row associated with this table.
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.. warning::
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At most one of ``filter_`` and ``append`` can be used in a
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:class:`Row`.
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:type row_key: bytes
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:param row_key: The key for the row being created.
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:type filter_: :class:`.RowFilter`
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:param filter_: (Optional) Filter to be used for conditional mutations.
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See :class:`.DirectRow` for more details.
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:type append: bool
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:param append: (Optional) Flag to determine if the row should be used
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for append mutations.
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:rtype: :class:`.DirectRow`
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:returns: A row owned by this table.
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:raises: :class:`ValueError <exceptions.ValueError>` if both
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``filter_`` and ``append`` are used.
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"""
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if append and filter_ is not None:
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raise ValueError('At most one of filter_ and append can be set')
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if append:
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return AppendRow(row_key, self)
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elif filter_ is not None:
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return ConditionalRow(row_key, self, filter_=filter_)
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else:
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return DirectRow(row_key, self)
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def __eq__(self, other):
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if not isinstance(other, self.__class__):
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return False
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return (other.table_id == self.table_id and
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other._instance == self._instance)
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def __ne__(self, other):
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return not self.__eq__(other)
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def create(self, initial_split_keys=None):
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"""Creates this table.
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.. note::
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Though a :class:`._generated_v2.table_pb2.Table` is also
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allowed (as the ``table`` property) in a create table request, we
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do not support it in this method. As mentioned in the
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:class:`Table` docstring, the name is the only useful property in
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the table proto.
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.. note::
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A create request returns a
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:class:`._generated_v2.table_pb2.Table` but we don't use
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this response. The proto definition allows for the inclusion of a
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``current_operation`` in the response, but it does not appear that
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the Cloud Bigtable API returns any operation.
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:type initial_split_keys: list
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:param initial_split_keys: (Optional) List of row keys that will be
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used to initially split the table into
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several tablets (Tablets are similar to
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HBase regions). Given two split keys,
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``"s1"`` and ``"s2"``, three tablets will be
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created, spanning the key ranges:
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``[, s1)``, ``[s1, s2)``, ``[s2, )``.
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"""
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split_pb = table_admin_messages_v2_pb2.CreateTableRequest.Split
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if initial_split_keys is not None:
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initial_split_keys = [
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split_pb(key=key) for key in initial_split_keys]
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request_pb = table_admin_messages_v2_pb2.CreateTableRequest(
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initial_splits=initial_split_keys or [],
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parent=self._instance.name,
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table_id=self.table_id,
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)
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client = self._instance._client
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# We expect a `._generated_v2.table_pb2.Table`
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client._table_stub.CreateTable(request_pb, client.timeout_seconds)
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def delete(self):
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"""Delete this table."""
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request_pb = table_admin_messages_v2_pb2.DeleteTableRequest(
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name=self.name)
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client = self._instance._client
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# We expect a `google.protobuf.empty_pb2.Empty`
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client._table_stub.DeleteTable(request_pb, client.timeout_seconds)
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def list_column_families(self):
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"""List the column families owned by this table.
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:rtype: dict
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:returns: Dictionary of column families attached to this table. Keys
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are strings (column family names) and values are
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:class:`.ColumnFamily` instances.
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:raises: :class:`ValueError <exceptions.ValueError>` if the column
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family name from the response does not agree with the computed
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name from the column family ID.
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"""
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request_pb = table_admin_messages_v2_pb2.GetTableRequest(
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name=self.name)
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client = self._instance._client
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# We expect a `._generated_v2.table_pb2.Table`
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table_pb = client._table_stub.GetTable(request_pb,
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client.timeout_seconds)
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result = {}
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for column_family_id, value_pb in table_pb.column_families.items():
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gc_rule = _gc_rule_from_pb(value_pb.gc_rule)
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column_family = self.column_family(column_family_id,
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gc_rule=gc_rule)
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result[column_family_id] = column_family
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return result
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def read_row(self, row_key, filter_=None):
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"""Read a single row from this table.
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:type row_key: bytes
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:param row_key: The key of the row to read from.
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:type filter_: :class:`.RowFilter`
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:param filter_: (Optional) The filter to apply to the contents of the
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row. If unset, returns the entire row.
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:rtype: :class:`.PartialRowData`, :data:`NoneType <types.NoneType>`
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:returns: The contents of the row if any chunks were returned in
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the response, otherwise :data:`None`.
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:raises: :class:`ValueError <exceptions.ValueError>` if a commit row
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chunk is never encountered.
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"""
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request_pb = _create_row_request(self.name, row_key=row_key,
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filter_=filter_)
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client = self._instance._client
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response_iterator = client._data_stub.ReadRows(request_pb,
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client.timeout_seconds)
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rows_data = PartialRowsData(response_iterator)
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rows_data.consume_all()
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if rows_data.state not in (rows_data.NEW_ROW, rows_data.START):
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raise ValueError('The row remains partial / is not committed.')
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if len(rows_data.rows) == 0:
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return None
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return rows_data.rows[row_key]
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def read_rows(self, start_key=None, end_key=None, limit=None,
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filter_=None):
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"""Read rows from this table.
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:type start_key: bytes
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:param start_key: (Optional) The beginning of a range of row keys to
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read from. The range will include ``start_key``. If
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left empty, will be interpreted as the empty string.
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:type end_key: bytes
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:param end_key: (Optional) The end of a range of row keys to read from.
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The range will not include ``end_key``. If left empty,
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will be interpreted as an infinite string.
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:type limit: int
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:param limit: (Optional) The read will terminate after committing to N
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rows' worth of results. The default (zero) is to return
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all results.
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:type filter_: :class:`.RowFilter`
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:param filter_: (Optional) The filter to apply to the contents of the
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specified row(s). If unset, reads every column in
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each row.
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:rtype: :class:`.PartialRowsData`
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:returns: A :class:`.PartialRowsData` convenience wrapper for consuming
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the streamed results.
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"""
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request_pb = _create_row_request(
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self.name, start_key=start_key, end_key=end_key, filter_=filter_,
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limit=limit)
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client = self._instance._client
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response_iterator = client._data_stub.ReadRows(request_pb,
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client.timeout_seconds)
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# We expect an iterator of `data_messages_v2_pb2.ReadRowsResponse`
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return PartialRowsData(response_iterator)
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def sample_row_keys(self):
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"""Read a sample of row keys in the table.
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The returned row keys will delimit contiguous sections of the table of
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approximately equal size, which can be used to break up the data for
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distributed tasks like mapreduces.
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The elements in the iterator are a SampleRowKeys response and they have
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the properties ``offset_bytes`` and ``row_key``. They occur in sorted
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order. The table might have contents before the first row key in the
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list and after the last one, but a key containing the empty string
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indicates "end of table" and will be the last response given, if
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present.
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.. note::
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Row keys in this list may not have ever been written to or read
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from, and users should therefore not make any assumptions about the
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row key structure that are specific to their use case.
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The ``offset_bytes`` field on a response indicates the approximate
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total storage space used by all rows in the table which precede
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``row_key``. Buffering the contents of all rows between two subsequent
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samples would require space roughly equal to the difference in their
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``offset_bytes`` fields.
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:rtype: :class:`grpc.framework.alpha._reexport._CancellableIterator`
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:returns: A cancel-able iterator. Can be consumed by calling ``next()``
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or by casting to a :class:`list` and can be cancelled by
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calling ``cancel()``.
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"""
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request_pb = data_messages_v2_pb2.SampleRowKeysRequest(
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table_name=self.name)
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client = self._instance._client
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response_iterator = client._data_stub.SampleRowKeys(
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request_pb, client.timeout_seconds)
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return response_iterator
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def _create_row_request(table_name, row_key=None, start_key=None, end_key=None,
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filter_=None, limit=None):
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"""Creates a request to read rows in a table.
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:type table_name: str
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:param table_name: The name of the table to read from.
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:type row_key: bytes
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:param row_key: (Optional) The key of a specific row to read from.
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:type start_key: bytes
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:param start_key: (Optional) The beginning of a range of row keys to
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read from. The range will include ``start_key``. If
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left empty, will be interpreted as the empty string.
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:type end_key: bytes
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:param end_key: (Optional) The end of a range of row keys to read from.
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The range will not include ``end_key``. If left empty,
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will be interpreted as an infinite string.
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:type filter_: :class:`.RowFilter`
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:param filter_: (Optional) The filter to apply to the contents of the
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specified row(s). If unset, reads the entire table.
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:type limit: int
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:param limit: (Optional) The read will terminate after committing to N
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rows' worth of results. The default (zero) is to return
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all results.
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:rtype: :class:`data_messages_v2_pb2.ReadRowsRequest`
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:returns: The ``ReadRowsRequest`` protobuf corresponding to the inputs.
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:raises: :class:`ValueError <exceptions.ValueError>` if both
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``row_key`` and one of ``start_key`` and ``end_key`` are set
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"""
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request_kwargs = {'table_name': table_name}
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if (row_key is not None and
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(start_key is not None or end_key is not None)):
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raise ValueError('Row key and row range cannot be '
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'set simultaneously')
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range_kwargs = {}
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if start_key is not None or end_key is not None:
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if start_key is not None:
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range_kwargs['start_key_closed'] = _to_bytes(start_key)
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if end_key is not None:
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range_kwargs['end_key_open'] = _to_bytes(end_key)
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if filter_ is not None:
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request_kwargs['filter'] = filter_.to_pb()
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if limit is not None:
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request_kwargs['rows_limit'] = limit
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message = data_messages_v2_pb2.ReadRowsRequest(**request_kwargs)
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if row_key is not None:
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message.rows.row_keys.append(_to_bytes(row_key))
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if range_kwargs:
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message.rows.row_ranges.add(**range_kwargs)
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return message
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