def build_key_from_values(self, schema, hash_key, range_key=None):
"""
Build a Key structure to be used for accessing items
in Amazon DynamoDB. This method takes the supplied hash_key
and optional range_key and validates them against the
schema. If there is a mismatch, a TypeError is raised.
Otherwise, a Python dict version of a Amazon DynamoDB Key
data structure is returned.
:type hash_key: int, float, str, or unicode
:param hash_key: The hash key of the item you are looking for.
The type of the hash key should match the type defined in
the schema.
:type range_key: int, float, str or unicode
:param range_key: The range key of the item your are looking for.
This should be supplied only if the schema requires a
range key. The type of the range key should match the
type defined in the schema.
"""
dynamodb_key = {}
dynamodb_value = dynamize_value(hash_key)
if dynamodb_value.keys()[0] != schema.hash_key_type:
msg = 'Hashkey must be of type: %s' % schema.hash_key_type
raise TypeError(msg)
dynamodb_key['HashKeyElement'] = dynamodb_value
if range_key is not None:
dynamodb_value = dynamize_value(range_key)
if dynamodb_value.keys()[0] != schema.range_key_type:
msg = 'RangeKey must be of type: %s' % schema.range_key_type
raise TypeError(msg)
dynamodb_key['RangeKeyElement'] = dynamodb_value
return dynamodb_key
def build_key_from_values(self, schema, hash_key, range_key=None):
"""
Build a Key structure to be used for accessing items
in Amazon DynamoDB. This method takes the supplied hash_key
and optional range_key and validates them against the
schema. If there is a mismatch, a TypeError is raised.
Otherwise, a Python dict version of a Amazon DynamoDB Key
data structure is returned.
:type hash_key: int, float, str, or unicode
:param hash_key: The hash key of the item you are looking for.
The type of the hash key should match the type defined in
the schema.
:type range_key: int, float, str or unicode
:param range_key: The range key of the item your are looking for.
This should be supplied only if the schema requires a
range key. The type of the range key should match the
type defined in the schema.
"""
dynamodb_key = {}
dynamodb_value = dynamize_value(hash_key)
if dynamodb_value.keys()[0] != schema.hash_key_type:
msg = 'Hashkey must be of type: %s' % schema.hash_key_type
raise TypeError(msg)
dynamodb_key['HashKeyElement'] = dynamodb_value
if range_key is not None:
dynamodb_value = dynamize_value(range_key)
if dynamodb_value.keys()[0] != schema.range_key_type:
msg = 'RangeKey must be of type: %s' % schema.range_key_type
raise TypeError(msg)
dynamodb_key['RangeKeyElement'] = dynamodb_value
return dynamodb_key
def dynamize_last_evaluated_key(self, last_evaluated_key):
"""
Convert a last_evaluated_key parameter into the data structure
required for Layer1.
"""
d = None
if last_evaluated_key:
hash_key = last_evaluated_key['HashKeyElement']
d = {'HashKeyElement': dynamize_value(hash_key)}
if 'RangeKeyElement' in last_evaluated_key:
range_key = last_evaluated_key['RangeKeyElement']
d['RangeKeyElement'] = dynamize_value(range_key)
return d
def dynamize_last_evaluated_key(self, last_evaluated_key):
"""
Convert a last_evaluated_key parameter into the data structure
required for Layer1.
"""
d = None
if last_evaluated_key:
hash_key = last_evaluated_key['HashKeyElement']
d = {'HashKeyElement': dynamize_value(hash_key)}
if 'RangeKeyElement' in last_evaluated_key:
range_key = last_evaluated_key['RangeKeyElement']
d['RangeKeyElement'] = dynamize_value(range_key)
return d
def dynamize_attribute_updates(self, pending_updates):
"""
Convert a set of pending item updates into the structure
required by Layer1.
"""
d = {}
for attr_name in pending_updates:
action, value = pending_updates[attr_name]
if value is None:
# DELETE without an attribute value
d[attr_name] = {"Action": action}
else:
d[attr_name] = {"Action": action,
"Value": dynamize_value(value)}
return d
def dynamize_attribute_updates(self, pending_updates):
"""
Convert a set of pending item updates into the structure
required by Layer1.
"""
d = {}
for attr_name in pending_updates:
action, value = pending_updates[attr_name]
if value is None:
# DELETE without an attribute value
d[attr_name] = {"Action": action}
else:
d[attr_name] = {
"Action": action,
"Value": dynamize_value(value)
}
return d
def dynamize_expected_value(self, expected_value):
"""
Convert an expected_value parameter into the data structure
required for Layer1.
"""
d = None
if expected_value:
d = {}
for attr_name in expected_value:
attr_value = expected_value[attr_name]
if attr_value is True:
attr_value = {'Exists': True}
elif attr_value is False:
attr_value = {'Exists': False}
else:
val = dynamize_value(expected_value[attr_name])
attr_value = {'Value': val}
d[attr_name] = attr_value
return d
def dynamize_expected_value(self, expected_value):
"""
Convert an expected_value parameter into the data structure
required for Layer1.
"""
d = None
if expected_value:
d = {}
for attr_name in expected_value:
attr_value = expected_value[attr_name]
if attr_value is True:
attr_value = {'Exists': True}
elif attr_value is False:
attr_value = {'Exists': False}
else:
val = dynamize_value(expected_value[attr_name])
attr_value = {'Value': val}
d[attr_name] = attr_value
return d
def dynamize_item(self, item):
d = {}
for attr_name in item:
d[attr_name] = dynamize_value(item[attr_name])
return d
def query(self, table, hash_key, range_key_condition=None,
attributes_to_get=None, request_limit=None,
max_results=None, consistent_read=False,
scan_index_forward=True, exclusive_start_key=None,
item_class=Item):
"""
Perform a query on the table.
:type table: :class:`boto.dynamodb.table.Table`
:param table: The Table object that is being queried.
:type hash_key: int|long|float|str|unicode
:param hash_key: The HashKey of the requested item. The
type of the value must match the type defined in the
schema for the table.
:type range_key_condition: :class:`boto.dynamodb.condition.Condition`
:param range_key_condition: A Condition object.
Condition object can be one of the following types:
EQ|LE|LT|GE|GT|BEGINS_WITH|BETWEEN
The only condition which expects or will accept two
values is 'BETWEEN', otherwise a single value should
be passed to the Condition constructor.
:type attributes_to_get: list
:param attributes_to_get: A list of attribute names.
If supplied, only the specified attribute names will
be returned. Otherwise, all attributes will be returned.
:type request_limit: int
:param request_limit: The maximum number of items to retrieve
from Amazon DynamoDB on each request. You may want to set
a specific request_limit based on the provisioned throughput
of your table. The default behavior is to retrieve as many
results as possible per request.
:type max_results: int
:param max_results: The maximum number of results that will
be retrieved from Amazon DynamoDB in total. For example,
if you only wanted to see the first 100 results from the
query, regardless of how many were actually available, you
could set max_results to 100 and the generator returned
from the query method will only yeild 100 results max.
:type consistent_read: bool
:param consistent_read: If True, a consistent read
request is issued. Otherwise, an eventually consistent
request is issued.
:type scan_index_forward: bool
:param scan_index_forward: Specified forward or backward
traversal of the index. Default is forward (True).
:type exclusive_start_key: list or tuple
:param exclusive_start_key: Primary key of the item from
which to continue an earlier query. This would be
provided as the LastEvaluatedKey in that query.
:type item_class: Class
:param item_class: Allows you to override the class used
to generate the items. This should be a subclass of
:class:`boto.dynamodb.item.Item`
:rtype: generator
"""
if range_key_condition:
rkc = self.dynamize_range_key_condition(range_key_condition)
else:
rkc = None
response = True
n = 0
while response:
if max_results and n == max_results:
break
if response is True:
pass
elif response.has_key("LastEvaluatedKey"):
lek = response['LastEvaluatedKey']
exclusive_start_key = self.dynamize_last_evaluated_key(lek)
else:
break
response = self.layer1.query(table.name,
dynamize_value(hash_key),
rkc, attributes_to_get, request_limit,
consistent_read, scan_index_forward,
exclusive_start_key,
object_hook=item_object_hook)
for item in response['Items']:
if max_results and n == max_results:
break
yield item_class(table, attrs=item)
n += 1
def encode(self, item):
for key, value in item.items():
item[key] = dynamize_value(value)
return item
def query(self,
table,
hash_key,
range_key_condition=None,
attributes_to_get=None,
request_limit=None,
max_results=None,
consistent_read=False,
scan_index_forward=True,
exclusive_start_key=None,
item_class=Item):
"""
Perform a query on the table.
:type table: :class:`boto.dynamodb.table.Table`
:param table: The Table object that is being queried.
:type hash_key: int|long|float|str|unicode
:param hash_key: The HashKey of the requested item. The
type of the value must match the type defined in the
schema for the table.
:type range_key_condition: :class:`boto.dynamodb.condition.Condition`
:param range_key_condition: A Condition object.
Condition object can be one of the following types:
EQ|LE|LT|GE|GT|BEGINS_WITH|BETWEEN
The only condition which expects or will accept two
values is 'BETWEEN', otherwise a single value should
be passed to the Condition constructor.
:type attributes_to_get: list
:param attributes_to_get: A list of attribute names.
If supplied, only the specified attribute names will
be returned. Otherwise, all attributes will be returned.
:type request_limit: int
:param request_limit: The maximum number of items to retrieve
from Amazon DynamoDB on each request. You may want to set
a specific request_limit based on the provisioned throughput
of your table. The default behavior is to retrieve as many
results as possible per request.
:type max_results: int
:param max_results: The maximum number of results that will
be retrieved from Amazon DynamoDB in total. For example,
if you only wanted to see the first 100 results from the
query, regardless of how many were actually available, you
could set max_results to 100 and the generator returned
from the query method will only yeild 100 results max.
:type consistent_read: bool
:param consistent_read: If True, a consistent read
request is issued. Otherwise, an eventually consistent
request is issued.
:type scan_index_forward: bool
:param scan_index_forward: Specified forward or backward
traversal of the index. Default is forward (True).
:type exclusive_start_key: list or tuple
:param exclusive_start_key: Primary key of the item from
which to continue an earlier query. This would be
provided as the LastEvaluatedKey in that query.
:type item_class: Class
:param item_class: Allows you to override the class used
to generate the items. This should be a subclass of
:class:`boto.dynamodb.item.Item`
:rtype: generator
"""
if range_key_condition:
rkc = self.dynamize_range_key_condition(range_key_condition)
else:
rkc = None
response = True
n = 0
while response:
if max_results and n == max_results:
break
if response is True:
pass
elif response.has_key("LastEvaluatedKey"):
lek = response['LastEvaluatedKey']
exclusive_start_key = self.dynamize_last_evaluated_key(lek)
else:
break
response = self.layer1.query(table.name,
dynamize_value(hash_key),
rkc,
attributes_to_get,
request_limit,
consistent_read,
scan_index_forward,
exclusive_start_key,
object_hook=item_object_hook)
for item in response['Items']:
if max_results and n == max_results:
break
yield item_class(table, attrs=item)
n += 1
def to_dict(self):
return {
'AttributeValueList': [dynamize_value(v) for v in self.values],
'ComparisonOperator': self.__class__.__name__
}
def encode_attribs(self, attribs):
for key, value in attribs.items():
attribs[key] = {'Value': dynamize_value(value)}
return attribs
def to_dict(self):
return {'AttributeValueList': [dynamize_value(self.v1)],
'ComparisonOperator': self.__class__.__name__}
def dynamize_item(self, item):
d = {}
for attr_name in item:
d[attr_name] = dynamize_value(item[attr_name])
return d
def to_dict(self):
values = (self.v1, self.v2)
return {'AttributeValueList': [dynamize_value(v) for v in values],
'ComparisonOperator': self.__class__.__name__}
def to_dict(self):
return {"AttributeValueList": [dynamize_value(self.v1)], "ComparisonOperator": self.__class__.__name__}
