LowVoltage/actions/delete_item.py
# coding: utf8
# Copyright 2014-2015 Vincent Jacques <vincent@vincent-jacques.net>
"""
When given a :class:`DeleteItem`, the connection will return a :class:`DeleteItemResponse`:
>>> connection(DeleteItem(table, {"h": 0}))
<LowVoltage.actions.delete_item.DeleteItemResponse ...>
Note that deleting the same item twice is not an error (deleting is idempotent). To know if an item was actually deleted, use :meth:`~DeleteItem.return_values_all_old`:
>>> connection(
... DeleteItem(table, {"h": 1})
... .return_values_all_old()
... ).attributes
{u'h': 1, u'gr': 8, u'gh': 1}
>>> print connection(
... DeleteItem(table, {"h": 1})
... .return_values_all_old()
... ).attributes
None
"""
import LowVoltage as _lv
import LowVoltage.testing as _tst
from .action import Action
from .conversion import _convert_dict_to_db, _convert_db_to_dict
from .next_gen_mixins import proxy
from .next_gen_mixins import (
ConditionExpression,
ExpressionAttributeNames,
ExpressionAttributeValues,
Key,
ReturnConsumedCapacity,
ReturnItemCollectionMetrics,
ReturnValues,
TableName,
)
from .return_types import ConsumedCapacity, ItemCollectionMetrics, _is_dict
class DeleteItemResponse(object):
"""
DeleteItemResponse()
The `DeleteItem response <http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_DeleteItem.html#API_DeleteItem_ResponseElements>`__
"""
def __init__(
self,
Attributes=None,
ConsumedCapacity=None,
ItemCollectionMetrics=None,
**dummy
):
self.__attributes = Attributes
self.__consumed_capacity = ConsumedCapacity
self.__item_collection_metrics = ItemCollectionMetrics
@property
def attributes(self):
"""
The previous attributes of the item you just deleted. If you used :meth:`~DeleteItem.return_values_all_old`.
:type: ``None`` or dict
"""
if _is_dict(self.__attributes):
return _convert_db_to_dict(self.__attributes)
@property
def consumed_capacity(self):
"""
The capacity consumed by the request. If you used :meth:`~DeleteItem.return_consumed_capacity_total` or :meth:`~DeleteItem.return_consumed_capacity_indexes`.
:type: ``None`` or :class:`.ConsumedCapacity`
"""
if _is_dict(self.__consumed_capacity):
return ConsumedCapacity(**self.__consumed_capacity)
@property
def item_collection_metrics(self):
"""
Metrics about the collection of the item you just deleted. If a LSI was touched and you used :meth:`~DeleteItem.return_item_collection_metrics_size`.
:type: ``None`` or :class:`.ItemCollectionMetrics`
"""
if _is_dict(self.__item_collection_metrics):
return ItemCollectionMetrics(**self.__item_collection_metrics)
class DeleteItem(Action):
"""
The `DeleteItem request <http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_DeleteItem.html#API_DeleteItem_RequestParameters>`__
"""
def __init__(self, table_name=None, key=None):
"""
Passing ``table_name`` to the constructor is like calling :meth:`table_name` on the new instance.
Passing ``key`` to the constructor is like calling :meth:`key` on the new instance.
"""
super(DeleteItem, self).__init__("DeleteItem", DeleteItemResponse)
self.__condition_expression = ConditionExpression(self)
self.__expression_attribute_names = ExpressionAttributeNames(self)
self.__expression_attribute_values = ExpressionAttributeValues(self)
self.__key = Key(self, key)
self.__return_consumed_capacity = ReturnConsumedCapacity(self)
self.__return_item_collection_metrics = ReturnItemCollectionMetrics(self)
self.__return_values = ReturnValues(self)
self.__table_name = TableName(self, table_name)
@property
def payload(self):
data = {}
data.update(self.__condition_expression.payload)
data.update(self.__expression_attribute_names.payload)
data.update(self.__expression_attribute_values.payload)
data.update(self.__key.payload)
data.update(self.__return_consumed_capacity.payload)
data.update(self.__return_item_collection_metrics.payload)
data.update(self.__return_values.payload)
data.update(self.__table_name.payload)
return data
@proxy
def table_name(self, table_name):
"""
>>> connection(
... DeleteItem(key={"h": 8})
... .table_name(table)
... )
<LowVoltage.actions.delete_item.DeleteItemResponse ...>
"""
return self.__table_name.set(table_name)
@proxy
def key(self, key):
"""
>>> connection(
... DeleteItem(table_name=table)
... .key({"h": 9})
... )
<LowVoltage.actions.delete_item.DeleteItemResponse ...>
"""
return self.__key.set(key)
@proxy
def condition_expression(self, expression):
"""
>>> connection(
... DeleteItem(table, {"h": 2})
... .condition_expression("#syn=:val")
... .expression_attribute_name("syn", "gr")
... .expression_attribute_value("val", 6)
... )
<LowVoltage.actions.delete_item.DeleteItemResponse ...>
"""
return self.__condition_expression.set(expression)
@proxy
def expression_attribute_name(self, synonym, name):
"""
See :meth:`condition_expression` for an example.
"""
return self.__expression_attribute_names.add(synonym, name)
@proxy
def expression_attribute_value(self, name, value):
"""
See :meth:`condition_expression` for an example.
"""
return self.__expression_attribute_values.add(name, value)
@proxy
def return_consumed_capacity_indexes(self):
"""
>>> c = connection(
... DeleteItem(table, {"h": 6})
... .return_consumed_capacity_indexes()
... ).consumed_capacity
>>> c.capacity_units
2.0
>>> c.table.capacity_units
1.0
>>> c.global_secondary_indexes["gsi"].capacity_units
1.0
"""
return self.__return_consumed_capacity.indexes()
@proxy
def return_consumed_capacity_total(self):
"""
>>> connection(
... DeleteItem(table, {"h": 5})
... .return_consumed_capacity_total()
... ).consumed_capacity.capacity_units
2.0
"""
return self.__return_consumed_capacity.total()
@proxy
def return_consumed_capacity_none(self):
"""
>>> print connection(
... DeleteItem(table, {"h": 7})
... .return_consumed_capacity_none()
... ).consumed_capacity
None
"""
return self.__return_consumed_capacity.none()
@proxy
def return_item_collection_metrics_size(self):
"""
>>> m = connection(
... DeleteItem(table2, {"h": 0, "r1": 0})
... .return_item_collection_metrics_size()
... ).item_collection_metrics
>>> m.item_collection_key
{u'h': 0}
>>> m.size_estimate_range_gb
[0.0, 1.0]
"""
return self.__return_item_collection_metrics.size()
@proxy
def return_item_collection_metrics_none(self):
"""
>>> print connection(
... DeleteItem(table2, {"h": 1, "r1": 0})
... .return_item_collection_metrics_none()
... ).item_collection_metrics
None
"""
return self.__return_item_collection_metrics.none()
@proxy
def return_values_all_old(self):
"""
>>> connection(
... DeleteItem(table, {"h": 3})
... .return_values_all_old()
... ).attributes
{u'h': 3, u'gr': 4, u'gh': 9}
"""
return self.__return_values.all_old()
@proxy
def return_values_none(self):
"""
>>> print connection(
... DeleteItem(table, {"h": 4})
... .return_values_none()
... ).attributes
None
"""
return self.__return_values.none()
class DeleteItemUnitTests(_tst.UnitTests):
def test_name(self):
self.assertEqual(DeleteItem("Table", {"hash": 42}).name, "DeleteItem")
def test_table_name_and_key(self):
self.assertEqual(
DeleteItem().table_name("Table").key({"hash": 42}).payload,
{
"TableName": "Table",
"Key": {"hash": {"N": "42"}},
}
)
def test_constructor(self):
self.assertEqual(
DeleteItem("Table", {"hash": 42}).payload,
{
"TableName": "Table",
"Key": {"hash": {"N": "42"}},
}
)
def test_return_values_none(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_values_none().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnValues": "NONE",
}
)
def test_return_values_all_old(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_values_all_old().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnValues": "ALL_OLD",
}
)
def test_return_consumed_capacity_total(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_consumed_capacity_total().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnConsumedCapacity": "TOTAL",
}
)
def test_return_consumed_capacity_indexes(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_consumed_capacity_indexes().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnConsumedCapacity": "INDEXES",
}
)
def test_return_consumed_capacity_none(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_consumed_capacity_none().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnConsumedCapacity": "NONE",
}
)
def test_return_item_collection_metrics_size(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_item_collection_metrics_size().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnItemCollectionMetrics": "SIZE",
}
)
def test_return_item_collection_metrics_none(self):
self.assertEqual(
DeleteItem("Table", {"hash": u"h"}).return_item_collection_metrics_none().payload,
{
"TableName": "Table",
"Key": {"hash": {"S": "h"}},
"ReturnItemCollectionMetrics": "NONE",
}
)
def test_expression_attribute_value(self):
self.assertEqual(
DeleteItem("Table", {"hash": 42}).expression_attribute_value("v", u"value").payload,
{
"TableName": "Table",
"Key": {"hash": {"N": "42"}},
"ExpressionAttributeValues": {":v": {"S": "value"}},
}
)
def test_expression_attribute_name(self):
self.assertEqual(
DeleteItem("Table", {"hash": 42}).expression_attribute_name("n", "path").payload,
{
"TableName": "Table",
"Key": {"hash": {"N": "42"}},
"ExpressionAttributeNames": {"#n": "path"},
}
)
def test_condition_expression(self):
self.assertEqual(
DeleteItem("Table", {"hash": 42}).condition_expression("a=b").payload,
{
"TableName": "Table",
"Key": {"hash": {"N": "42"}},
"ConditionExpression": "a=b",
}
)
class DeleteItemResponseUnitTests(_tst.UnitTests):
def test_all_none(self):
r = DeleteItemResponse()
self.assertIsNone(r.attributes)
self.assertIsNone(r.consumed_capacity)
self.assertIsNone(r.item_collection_metrics)
def test_all_set(self):
unprocessed_keys = object()
r = DeleteItemResponse(Attributes={"h": {"S": "a"}}, ConsumedCapacity={}, ItemCollectionMetrics={})
self.assertEqual(r.attributes, {"h": "a"})
self.assertIsInstance(r.consumed_capacity, ConsumedCapacity)
self.assertIsInstance(r.item_collection_metrics, ItemCollectionMetrics)