"""
DynamoDB Client
===============
"""
import collections
import json
import logging
import os
import select as _select
import socket
import ssl
import time
from tornado import concurrent, gen, httpclient, ioloop
import tornado_aws
from tornado_aws import exceptions as aws_exceptions
from sprockets_dynamodb import exceptions, utils
# Stub Python3 exceptions for Python 2.7
try:
ConnectionError
except NameError: # pragma: nocover
class ConnectionError(Exception):
pass
class ConnectionResetError(Exception):
pass
class TimeoutError(Exception):
pass
LOGGER = logging.getLogger(__name__)
Measurement = collections.namedtuple(
'Measurement',
['timestamp', 'action', 'table', 'attempt', 'duration', 'error'])
[docs]class Client(object):
"""
Asynchronous DynamoDB Client
:keyword str region: AWS region to send requests to
:keyword str access_key: AWS access key. If unspecified, this
defaults to the :envvar:`AWS_ACCESS_KEY_ID` environment
variable and will fall back to using the AWS CLI credentials
file. See :class:`tornado_aws.client.AsyncAWSClient` for
more details.
:keyword str secret_key: AWS secret used to secure API calls.
If unspecified, this defaults to the :envvar:`AWS_SECRET_ACCESS_KEY`
environment variable and will fall back to using the AWS CLI
credentials as described in :class:`tornado_aws.client.AsyncAWSClient`.
:keyword str profile: optional profile to use in AWS API calls.
If unspecified, this defaults to the :envvar:`AWS_DEFAULT_PROFILE`
environment variable or ``default`` if unset.
:keyword str endpoint: DynamoDB endpoint to contact. If unspecified,
the default is determined by the region.
:keyword int max_clients: optional maximum number of HTTP requests
that may be performed in parallel.
:keyword int max_retries: Maximum number of times to retry a request when
if fails under certain conditions. Can also be set with the
:envvar:`DYNAMODB_MAX_RETRIES` environment variable.
:keyword method instrumentation_callback: A method that is invoked with a
list of measurements that were collected during the execution of an
individual action.
:keyword method on_error_callback: A method that is invoked when there is
a request exception that can not automatically be retried or the
maximum number of retries has been exceeded for a request.
Any of the methods invoked in the client can raise the following
exceptions:
- :exc:`sprockets_dynamodb.exceptions.DynamoDBException`
- :exc:`sprockets_dynamodb.exceptions.ConfigNotFound`
- :exc:`sprockets_dynamodb.exceptions.NoCredentialsError`
- :exc:`sprockets_dynamodb.exceptions.NoProfileError`
- :exc:`sprockets_dynamodb.exceptions.TimeoutException`
- :exc:`sprockets_dynamodb.exceptions.RequestException`
- :exc:`sprockets_dynamodb.exceptions.InternalFailure`
- :exc:`sprockets_dynamodb.exceptions.LimitExceeded`
- :exc:`sprockets_dynamodb.exceptions.MissingParameter`
- :exc:`sprockets_dynamodb.exceptions.OptInRequired`
- :exc:`sprockets_dynamodb.exceptions.ResourceInUse`
- :exc:`sprockets_dynamodb.exceptions.RequestExpired`
- :exc:`sprockets_dynamodb.exceptions.ServiceUnavailable`
- :exc:`sprockets_dynamodb.exceptions.ValidationException`
Create an instance of this class to interact with a DynamoDB
server. A :class:`tornado_aws.client.AsyncAWSClient` instance
implements the AWS API wrapping and this class provides the
DynamoDB specifics.
"""
DEFAULT_MAX_RETRIES = 3
def __init__(self, **kwargs):
self.logger = LOGGER.getChild(self.__class__.__name__)
if os.environ.get('DYNAMODB_ENDPOINT', None):
kwargs.setdefault('endpoint', os.environ['DYNAMODB_ENDPOINT'])
self._client = tornado_aws.AsyncAWSClient('dynamodb', **kwargs)
self._ioloop = kwargs.get('io_loop', ioloop.IOLoop.current())
self._max_retries = kwargs.get(
'max_retries', os.environ.get(
'DYNAMODB_MAX_RETRIES', self.DEFAULT_MAX_RETRIES))
self._instrumentation_callback = kwargs.get('instrumentation_callback')
self._on_error = kwargs.get('on_error_callback')
[docs] def create_table(self, table_definition):
"""
Invoke the ``CreateTable`` function.
:param dict table_definition: description of the table to
create according to `CreateTable`_
:rtype: tornado.concurrent.Future
.. _CreateTable: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_CreateTable.html
"""
return self.execute('CreateTable', table_definition)
[docs] def update_table(self, table_definition):
"""
Modifies the provisioned throughput settings, global secondary
indexes, or DynamoDB Streams settings for a given table.
You can only perform one of the following operations at once:
- Modify the provisioned throughput settings of the table.
- Enable or disable Streams on the table.
- Remove a global secondary index from the table.
- Create a new global secondary index on the table. Once the index
begins back-filling, you can use *UpdateTable* to perform other
operations.
*UpdateTable* is an asynchronous operation; while it is executing, the
table status changes from ``ACTIVE`` to ``UPDATING``. While it is
``UPDATING``, you cannot issue another *UpdateTable* request. When the
table returns to the ``ACTIVE`` state, the *UpdateTable* operation is
complete.
:param dict table_definition: description of the table to
update according to `UpdateTable`_
:rtype: tornado.concurrent.Future
.. _UpdateTable: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_UpdateTable.html
"""
raise NotImplementedError
[docs] def delete_table(self, table_name):
"""
Invoke the `DeleteTable`_ function. The DeleteTable operation deletes a
table and all of its items. After a DeleteTable request, the specified
table is in the DELETING state until DynamoDB completes the deletion.
If the table is in the ACTIVE state, you can delete it. If a table is
in CREATING or UPDATING states, then a
:py:exc:`~sprockets_dynamodb.exceptions.ResourceInUse`
exception is raised. If the specified table does not exist, a
:exc:`~sprockets_dynamodb.exceptions.ResourceNotFound`
exception is raised. If table is already in the DELETING state, no
error is returned.
:param str table_name: name of the table to describe.
:rtype: tornado.concurrent.Future
.. _DeleteTable: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_DeleteTable.html
"""
return self.execute('DeleteTable', {'TableName': table_name})
[docs] def describe_table(self, table_name):
"""
Invoke the `DescribeTable`_ function.
:param str table_name: name of the table to describe.
:rtype: tornado.concurrent.Future
.. _DescribeTable: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_DescribeTable.html
"""
return self.execute('DescribeTable', {'TableName': table_name})
[docs] def list_tables(self, exclusive_start_table_name=None, limit=None):
"""
Invoke the `ListTables`_ function.
Returns an array of table names associated with the current account
and endpoint. The output from *ListTables* is paginated, with each page
returning a maximum of ``100`` table names.
:param str exclusive_start_table_name: The first table name that this
operation will evaluate. Use the value that was returned for
``LastEvaluatedTableName`` in a previous operation, so that you can
obtain the next page of results.
:param int limit: A maximum number of table names to return. If this
parameter is not specified, the limit is ``100``.
.. _ListTables: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_ListTables.html
"""
payload = {}
if exclusive_start_table_name:
payload['ExclusiveStartTableName'] = exclusive_start_table_name
if limit:
payload['Limit'] = limit
return self.execute('ListTables', payload)
[docs] def put_item(self, table_name, item,
condition_expression=None,
expression_attribute_names=None,
expression_attribute_values=None,
return_consumed_capacity=None,
return_item_collection_metrics=None,
return_values=None):
"""Invoke the `PutItem`_ function, creating a new item, or replaces an
old item with a new item. If an item that has the same primary key as
the new item already exists in the specified table, the new item
completely replaces the existing item. You can perform a conditional
put operation (add a new item if one with the specified primary key
doesn't exist), or replace an existing item if it has certain attribute
values.
For more information about using this API, see Working with Items in
the Amazon DynamoDB Developer Guide.
:param str table_name: The table to put the item to
:param dict item: A map of attribute name/value pairs, one for each
attribute. Only the primary key attributes are required; you can
optionally provide other attribute name-value pairs for the item.
You must provide all of the attributes for the primary key. For
example, with a simple primary key, you only need to provide a
value for the partition key. For a composite primary key, you must
provide both values for both the partition key and the sort key.
If you specify any attributes that are part of an index key, then
the data types for those attributes must match those of the schema
in the table's attribute definition.
:param str condition_expression: A condition that must be satisfied in
order for a conditional *PutItem* operation to succeed. See the
`AWS documentation for ConditionExpression <http://docs.aws.amazon.
com/amazondynamodb/latest/APIReference/API_PutItem.html#DDB-Put
Item-request-ConditionExpression>`_ for more information.
:param dict expression_attribute_names: One or more substitution tokens
for attribute names in an expression. See the `AWS documentation
for ExpressionAttributeNames <http://docs.aws.amazon.com/amazon
dynamodb/latest/APIReference/API_PutItem.html#DDB-PutItem-request-
ExpressionAttributeNames>`_ for more information.
:param dict expression_attribute_values: One or more values that can be
substituted in an expression. See the `AWS documentation
for ExpressionAttributeValues <http://docs.aws.amazon.com/amazon
dynamodb/latest/APIReference/API_PutItem.html#DDB-PutItem-request-
ExpressionAttributeValues>`_ for more information.
:param str return_consumed_capacity: Determines the level of detail
about provisioned throughput consumption that is returned in the
response. Should be ``None`` or one of ``INDEXES`` or ``TOTAL``
:param str return_item_collection_metrics: Determines whether item
collection metrics are returned.
:param str return_values: Use ``ReturnValues`` if you want to get the
item attributes as they appeared before they were updated with the
``PutItem`` request.
:rtype: tornado.concurrent.Future
.. _PutItem: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_PutItem.html
"""
payload = {'TableName': table_name, 'Item': utils.marshall(item)}
if condition_expression:
payload['ConditionExpression'] = condition_expression
if expression_attribute_names:
payload['ExpressionAttributeNames'] = expression_attribute_names
if expression_attribute_values:
payload['ExpressionAttributeValues'] = expression_attribute_values
if return_consumed_capacity:
payload['ReturnConsumedCapacity'] = return_consumed_capacity
if return_item_collection_metrics:
payload['ReturnItemCollectionMetrics'] = 'SIZE'
if return_values:
_validate_return_values(return_values)
payload['ReturnValues'] = return_values
return self.execute('PutItem', payload)
[docs] def get_item(self, table_name, key_dict,
consistent_read=False,
expression_attribute_names=None,
projection_expression=None,
return_consumed_capacity=None):
"""
Invoke the `GetItem`_ function.
:param str table_name: table to retrieve the item from
:param dict key_dict: key to use for retrieval. This will
be marshalled for you so a native :class:`dict` works.
:param bool consistent_read: Determines the read consistency model: If
set to :py:data`True`, then the operation uses strongly consistent
reads; otherwise, the operation uses eventually consistent reads.
:param dict expression_attribute_names: One or more substitution tokens
for attribute names in an expression.
:param str projection_expression: A string that identifies one or more
attributes to retrieve from the table. These attributes can include
scalars, sets, or elements of a JSON document. The attributes in
the expression must be separated by commas. If no attribute names
are specified, then all attributes will be returned. If any of the
requested attributes are not found, they will not appear in the
result.
:param str return_consumed_capacity: Determines the level of detail
about provisioned throughput consumption that is returned in the
response:
- INDEXES: The response includes the aggregate consumed
capacity for the operation, together with consumed capacity for
each table and secondary index that was accessed. Note that
some operations, such as *GetItem* and *BatchGetItem*, do not
access any indexes at all. In these cases, specifying INDEXES
will only return consumed capacity information for table(s).
- TOTAL: The response includes only the aggregate consumed
capacity for the operation.
- NONE: No consumed capacity details are included in the
response.
:rtype: tornado.concurrent.Future
.. _GetItem: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_GetItem.html
"""
payload = {'TableName': table_name,
'Key': utils.marshall(key_dict),
'ConsistentRead': consistent_read}
if expression_attribute_names:
payload['ExpressionAttributeNames'] = expression_attribute_names
if projection_expression:
payload['ProjectionExpression'] = projection_expression
if return_consumed_capacity:
_validate_return_consumed_capacity(return_consumed_capacity)
payload['ReturnConsumedCapacity'] = return_consumed_capacity
return self.execute('GetItem', payload)
[docs] def update_item(self, table_name, key_dict,
condition_expression=None,
update_expression=None,
expression_attribute_names=None,
expression_attribute_values=None,
return_consumed_capacity=None,
return_item_collection_metrics=None,
return_values=None):
"""Invoke the `UpdateItem`_ function.
Edits an existing item's attributes, or adds a new item to the table
if it does not already exist. You can put, delete, or add attribute
values. You can also perform a conditional update on an existing item
(insert a new attribute name-value pair if it doesn't exist, or replace
an existing name-value pair if it has certain expected attribute
values).
:param str table_name: The name of the table that contains the item to
update
:param dict key_dict: A dictionary of key/value pairs that are used to
define the primary key values for the item. For the primary key,
you must provide all of the attributes. For example, with a simple
primary key, you only need to provide a value for the partition
key. For a composite primary key, you must provide values for both
the partition key and the sort key.
:param str condition_expression: A condition that must be satisfied in
order for a conditional *UpdateItem* operation to succeed. One of:
``attribute_exists``, ``attribute_not_exists``, ``attribute_type``,
``contains``, ``begins_with``, ``size``, ``=``, ``<>``, ``<``,
``>``, ``<=``, ``>=``, ``BETWEEN``, ``IN``, ``AND``, ``OR``, or
``NOT``.
:param str update_expression: An expression that defines one or more
attributes to be updated, the action to be performed on them, and
new value(s) for them.
:param dict expression_attribute_names: One or more substitution tokens
for attribute names in an expression.
:param dict expression_attribute_values: One or more values that can be
substituted in an expression.
:param str return_consumed_capacity: Determines the level of detail
about provisioned throughput consumption that is returned in the
response. See the `AWS documentation
for ReturnConsumedCapacity <http://docs.aws.amazon.com/
amazondynamodb/latest/APIReference/API_UpdateItem.html#DDB-Update
Item-request-ReturnConsumedCapacity>`_ for more information.
:param str return_item_collection_metrics: Determines whether item
collection metrics are returned.
:param str return_values: Use ReturnValues if you want to get the item
attributes as they appeared either before or after they were
updated. See the `AWS documentation for ReturnValues <http://docs.
aws.amazon.com/amazondynamodb/latest/APIReference/
API_UpdateItem.html#DDB-UpdateItem-request-ReturnValues>`_
:rtype: tornado.concurrent.Future
.. _UpdateItem: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_UpdateItem.html
"""
payload = {'TableName': table_name,
'Key': utils.marshall(key_dict),
'UpdateExpression': update_expression}
if condition_expression:
payload['ConditionExpression'] = condition_expression
if expression_attribute_names:
payload['ExpressionAttributeNames'] = expression_attribute_names
if expression_attribute_values:
payload['ExpressionAttributeValues'] = \
utils.marshall(expression_attribute_values)
if return_consumed_capacity:
_validate_return_consumed_capacity(return_consumed_capacity)
payload['ReturnConsumedCapacity'] = return_consumed_capacity
if return_item_collection_metrics:
_validate_return_item_collection_metrics(
return_item_collection_metrics)
payload['ReturnItemCollectionMetrics'] = \
return_item_collection_metrics
if return_values:
_validate_return_values(return_values)
payload['ReturnValues'] = return_values
return self.execute('UpdateItem', payload)
[docs] def delete_item(self, table_name, key_dict,
condition_expression=None,
expression_attribute_names=None,
expression_attribute_values=None,
return_consumed_capacity=None,
return_item_collection_metrics=None,
return_values=False):
"""Invoke the `DeleteItem`_ function that deletes a single item in a
table by primary key. You can perform a conditional delete operation
that deletes the item if it exists, or if it has an expected attribute
value.
:param str table_name: The name of the table from which to delete the
item.
:param dict key_dict: A map of attribute names to ``AttributeValue``
objects, representing the primary key of the item to delete. For
the primary key, you must provide all of the attributes. For
example, with a simple primary key, you only need to provide a
value for the partition key. For a composite primary key, you must
provide values for both the partition key and the sort key.
:param str condition_expression: A condition that must be satisfied in
order for a conditional *DeleteItem* to succeed. See the `AWS
documentation for ConditionExpression <http://docs.aws.amazon.com/
amazondynamodb/latest/APIReference/API_DeleteItem.html#DDB-Delete
Item-request-ConditionExpression>`_ for more information.
:param dict expression_attribute_names: One or more substitution tokens
for attribute names in an expression. See the `AWS documentation
for ExpressionAttributeNames <http://docs.aws.amazon.com/
amazondynamodb/latest/APIReference/API_DeleteItem.html#DDB-Delete
Item-request-ExpressionAttributeNames>`_ for more information.
:param dict expression_attribute_values: One or more values that can be
substituted in an expression. See the `AWS documentation
for ExpressionAttributeValues <http://docs.aws.amazon.com/
amazondynamodb/latest/APIReference/API_DeleteItem.html#DDB-Delete
Item-request-ExpressionAttributeValues>`_ for more information.
:param str return_consumed_capacity: Determines the level of detail
about provisioned throughput consumption that is returned in the
response. See the `AWS documentation
for ReturnConsumedCapacity <http://docs.aws.amazon.com/
amazondynamodb/latest/APIReference/API_DeleteItem.html#DDB-Delete
Item-request-ReturnConsumedCapacity>`_ for more information.
:param str return_item_collection_metrics: Determines whether item
collection metrics are returned.
:param str return_values: Return the item attributes as they appeared
before they were deleted.
.. _DeleteItem: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_DeleteItem.html
"""
payload = {'TableName': table_name, 'Key': utils.marshall(key_dict)}
if condition_expression:
payload['ConditionExpression'] = condition_expression
if expression_attribute_names:
payload['ExpressionAttributeNames'] = expression_attribute_names
if expression_attribute_values:
payload['ExpressionAttributeValues'] = \
utils.marshall(expression_attribute_values)
if return_consumed_capacity:
_validate_return_consumed_capacity(return_consumed_capacity)
payload['ReturnConsumedCapacity'] = return_consumed_capacity
if return_item_collection_metrics:
_validate_return_item_collection_metrics(
return_item_collection_metrics)
payload['ReturnItemCollectionMetrics'] = \
return_item_collection_metrics
if return_values:
_validate_return_values(return_values)
payload['ReturnValues'] = return_values
return self.execute('DeleteItem', payload)
[docs] def batch_get_item(self):
"""Invoke the `BatchGetItem`_ function.
.. _BatchGetItem: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_BatchGetItem.html
"""
raise NotImplementedError
[docs] def batch_write_item(self):
"""Invoke the `BatchWriteItem`_ function.
.. _BatchWriteItem: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_BatchWriteItem.html
"""
raise NotImplementedError
[docs] def query(self, table_name,
index_name=None,
consistent_read=None,
key_condition_expression=None,
filter_expression=None,
expression_attribute_names=None,
expression_attribute_values=None,
projection_expression=None,
select=None,
exclusive_start_key=None,
limit=None,
scan_index_forward=True,
return_consumed_capacity=None):
"""A `Query`_ operation uses the primary key of a table or a secondary
index to directly access items from that table or index.
:param str table_name: The name of the table containing the requested
items.
:param bool consistent_read: Determines the read consistency model: If
set to ``True``, then the operation uses strongly consistent reads;
otherwise, the operation uses eventually consistent reads. Strongly
consistent reads are not supported on global secondary indexes. If
you query a global secondary index with ``consistent_read`` set to
``True``, you will receive a
:exc:`~sprockets_dynamodb.exceptions.ValidationException`.
:param dict exclusive_start_key: The primary key of the first
item that this operation will evaluate. Use the value that was
returned for ``LastEvaluatedKey`` in the previous operation. In a
parallel scan, a *Scan* request that includes
``exclusive_start_key`` must specify the same segment whose
previous *Scan* returned the corresponding value of
``LastEvaluatedKey``.
:param dict expression_attribute_names: One or more substitution tokens
for attribute names in an expression.
:param dict expression_attribute_values: One or more values that can be
substituted in an expression.
:param str filter_expression: A string that contains conditions that
DynamoDB applies after the *Query* operation, but before the data
is returned to you. Items that do not satisfy the criteria are not
returned. Note that a filter expression is applied after the items
have already been read; the process of filtering does not consume
any additional read capacity units. For more information, see
`Filter Expressions <http://docs.aws.amazon.com/amazondynamodb/
latest/developerguide/QueryAndScan.html#FilteringResults>`_ in the
Amazon DynamoDB Developer Guide.
:param str projection_expression:
:param str index_name: The name of a secondary index to query. This
index can be any local secondary index or global secondary index.
Note that if you use this parameter, you must also provide
``table_name``.
:param int limit: The maximum number of items to evaluate (not
necessarily the number of matching items). If DynamoDB processes
the number of items up to the limit while processing the results,
it stops the operation and returns the matching values up to that
point, and a key in ``LastEvaluatedKey`` to apply in a subsequent
operation, so that you can pick up where you left off. Also, if the
processed data set size exceeds 1 MB before DynamoDB reaches this
limit, it stops the operation and returns the matching values up to
the limit, and a key in ``LastEvaluatedKey`` to apply in a
subsequent operation to continue the operation. For more
information, see `Query and Scan <http://docs.aws.amazon.com/amazo
ndynamodb/latest/developerguide/QueryAndScan.html>`_ in the Amazon
DynamoDB Developer Guide.
:param str return_consumed_capacity: Determines the level of detail
about provisioned throughput consumption that is returned in the
response:
- ``INDEXES``: The response includes the aggregate consumed
capacity for the operation, together with consumed capacity for
each table and secondary index that was accessed. Note that
some operations, such as *GetItem* and *BatchGetItem*, do not
access any indexes at all. In these cases, specifying
``INDEXES`` will only return consumed capacity information for
table(s).
- ``TOTAL``: The response includes only the aggregate consumed
capacity for the operation.
- ``NONE``: No consumed capacity details are included in the
response.
:param bool scan_index_forward: Specifies the order for index
traversal: If ``True`` (default), the traversal is performed in
ascending order; if ``False``, the traversal is performed in
descending order. Items with the same partition key value are
stored in sorted order by sort key. If the sort key data type is
*Number*, the results are stored in numeric order. For type
*String*, the results are stored in order of ASCII character code
values. For type *Binary*, DynamoDB treats each byte of the binary
data as unsigned. If set to ``True``, DynamoDB returns the results
in the order in which they are stored (by sort key value). This is
the default behavior. If set to ``False``, DynamoDB reads the
results in reverse order by sort key value, and then returns the
results to the client.
:param str select: The attributes to be returned in the result. You can
retrieve all item attributes, specific item attributes, the count
of matching items, or in the case of an index, some or all of the
attributes projected into the index. Possible values are:
- ``ALL_ATTRIBUTES``: Returns all of the item attributes from the
specified table or index. If you query a local secondary index,
then for each matching item in the index DynamoDB will fetch
the entire item from the parent table. If the index is
configured to project all item attributes, then all of the data
can be obtained from the local secondary index, and no fetching
is required.
- ``ALL_PROJECTED_ATTRIBUTES``: Allowed only when querying an
index. Retrieves all attributes that have been projected into
the index. If the index is configured to project all
attributes, this return value is equivalent to specifying
``ALL_ATTRIBUTES``.
- ``COUNT``: Returns the number of matching items, rather than
the matching items themselves.
:rtype: dict
.. _Query: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_Query.html
"""
payload = {'TableName': table_name,
'ScanIndexForward': scan_index_forward}
if index_name:
payload['IndexName'] = index_name
if consistent_read is not None:
payload['ConsistentRead'] = consistent_read
if key_condition_expression:
payload['KeyConditionExpression'] = key_condition_expression
if filter_expression:
payload['FilterExpression'] = filter_expression
if expression_attribute_names:
payload['ExpressionAttributeNames'] = expression_attribute_names
if expression_attribute_values:
payload['ExpressionAttributeValues'] = \
utils.marshall(expression_attribute_values)
if projection_expression:
payload['ProjectionExpression'] = projection_expression
if select:
_validate_select(select)
payload['Select'] = select
if exclusive_start_key:
payload['ExclusiveStartKey'] = utils.marshall(exclusive_start_key)
if limit:
payload['Limit'] = limit
if return_consumed_capacity:
_validate_return_consumed_capacity(return_consumed_capacity)
payload['ReturnConsumedCapacity'] = return_consumed_capacity
return self.execute('Query', payload)
[docs] def scan(self,
table_name,
index_name=None,
consistent_read=None,
projection_expression=None,
filter_expression=None,
expression_attribute_names=None,
expression_attribute_values=None,
segment=None,
total_segments=None,
select=None,
limit=None,
exclusive_start_key=None,
return_consumed_capacity=None):
"""The `Scan`_ operation returns one or more items and item attributes
by accessing every item in a table or a secondary index.
If the total number of scanned items exceeds the maximum data set size
limit of 1 MB, the scan stops and results are returned to the user as a
``LastEvaluatedKey`` value to continue the scan in a subsequent
operation. The results also include the number of items exceeding the
limit. A scan can result in no table data meeting the filter criteria.
By default, Scan operations proceed sequentially; however, for faster
performance on a large table or secondary index, applications can
request a parallel *Scan* operation by providing the ``segment`` and
``total_segments`` parameters. For more information, see
`Parallel Scan <http://docs.aws.amazon.com/amazondynamodb/latest/
developerguide/QueryAndScan.html#QueryAndScanParallelScan>`_ in the
Amazon DynamoDB Developer Guide.
By default, *Scan* uses eventually consistent reads when accessing the
data in a table; therefore, the result set might not include the
changes to data in the table immediately before the operation began. If
you need a consistent copy of the data, as of the time that the *Scan*
begins, you can set the ``consistent_read`` parameter to ``True``.
:rtype: dict
.. _Scan: http://docs.aws.amazon.com/amazondynamodb/
latest/APIReference/API_Scan.html
"""
payload = {'TableName': table_name}
if index_name:
payload['IndexName'] = index_name
if consistent_read is not None:
payload['ConsistentRead'] = consistent_read
if filter_expression:
payload['FilterExpression'] = filter_expression
if expression_attribute_names:
payload['ExpressionAttributeNames'] = expression_attribute_names
if expression_attribute_values:
payload['ExpressionAttributeValues'] = \
utils.marshall(expression_attribute_values)
if projection_expression:
payload['ProjectionExpression'] = projection_expression
if segment:
payload['Segment'] = segment
if total_segments:
payload['TotalSegments'] = total_segments
if select:
_validate_select(select)
payload['Select'] = select
if exclusive_start_key:
payload['ExclusiveStartKey'] = utils.marshall(exclusive_start_key)
if limit:
payload['Limit'] = limit
if return_consumed_capacity:
_validate_return_consumed_capacity(return_consumed_capacity)
payload['ReturnConsumedCapacity'] = return_consumed_capacity
return self.execute('Scan', payload)
[docs] @gen.coroutine
def execute(self, action, parameters):
"""
Execute a DynamoDB action with the given parameters. The method will
retry requests that failed due to OS level errors or when being
throttled by DynamoDB.
:param str action: DynamoDB action to invoke
:param dict parameters: parameters to send into the action
:rtype: tornado.concurrent.Future
This method creates a future that will resolve to the result
of calling the specified DynamoDB function. It does it's best
to unwrap the response from the function to make life a little
easier for you. It does this for the ``GetItem`` and ``Query``
functions currently.
:raises:
:exc:`~sprockets_dynamodb.exceptions.DynamoDBException`
:exc:`~sprockets_dynamodb.exceptions.ConfigNotFound`
:exc:`~sprockets_dynamodb.exceptions.NoCredentialsError`
:exc:`~sprockets_dynamodb.exceptions.NoProfileError`
:exc:`~sprockets_dynamodb.exceptions.TimeoutException`
:exc:`~sprockets_dynamodb.exceptions.RequestException`
:exc:`~sprockets_dynamodb.exceptions.InternalFailure`
:exc:`~sprockets_dynamodb.exceptions.LimitExceeded`
:exc:`~sprockets_dynamodb.exceptions.MissingParameter`
:exc:`~sprockets_dynamodb.exceptions.OptInRequired`
:exc:`~sprockets_dynamodb.exceptions.ResourceInUse`
:exc:`~sprockets_dynamodb.exceptions.RequestExpired`
:exc:`~sprockets_dynamodb.exceptions.ResourceNotFound`
:exc:`~sprockets_dynamodb.exceptions.ServiceUnavailable`
:exc:`~sprockets_dynamodb.exceptions.ThroughputExceeded`
:exc:`~sprockets_dynamodb.exceptions.ValidationException`
"""
measurements = collections.deque([], self._max_retries)
for attempt in range(1, self._max_retries + 1):
try:
result = yield self._execute(
action, parameters, attempt, measurements)
except (exceptions.InternalServerError,
exceptions.RequestException,
exceptions.ThrottlingException,
exceptions.ThroughputExceeded,
exceptions.ServiceUnavailable) as error:
if attempt == self._max_retries:
if self._instrumentation_callback:
self._instrumentation_callback(measurements)
self._on_exception(error)
duration = self._sleep_duration(attempt)
self.logger.warning('%r on attempt %i, sleeping %.2f seconds',
error, attempt, duration)
yield gen.sleep(duration)
except exceptions.DynamoDBException as error:
if self._instrumentation_callback:
self._instrumentation_callback(measurements)
self._on_exception(error)
else:
if self._instrumentation_callback:
self._instrumentation_callback(measurements)
self.logger.debug('%s result: %r', action, result)
raise gen.Return(_unwrap_result(action, result))
[docs] def set_error_callback(self, callback):
"""Assign a method to invoke when a request has encountered an
unrecoverable error in an action execution.
:param method callback: The method to invoke
"""
self.logger.debug('Setting error callback: %r', callback)
self._on_error = callback
[docs] def set_instrumentation_callback(self, callback):
"""Assign a method to invoke when a request has completed gathering
measurements.
:param method callback: The method to invoke
"""
self.logger.debug('Setting instrumentation callback: %r', callback)
self._instrumentation_callback = callback
def _execute(self, action, parameters, attempt, measurements):
"""Invoke a DynamoDB action
:param str action: DynamoDB action to invoke
:param dict parameters: parameters to send into the action
:param int attempt: Which attempt number this is
:param list measurements: A list for accumulating request measurements
:rtype: tornado.concurrent.Future
"""
future = concurrent.TracebackFuture()
start = time.time()
def handle_response(request):
"""Invoked by the IOLoop when fetch has a response to process.
:param tornado.concurrent.Future request: The request future
"""
self._on_response(
action, parameters.get('TableName', 'Unknown'), attempt,
start, request, future, measurements)
ioloop.IOLoop.current().add_future(self._client.fetch(
'POST', '/',
body=json.dumps(parameters).encode('utf-8'),
headers={
'x-amz-target': 'DynamoDB_20120810.{}'.format(action),
'Content-Type': 'application/x-amz-json-1.0',
}), handle_response)
return future
def _on_exception(self, error):
"""Handle exceptions that can not be retried.
:param error: The exception that was raised
:type error: sprockets_dynamodb.exceptions.DynamoDBException
"""
if not self._on_error:
raise error
self._on_error(error)
def _on_response(self, action, table, attempt, start, response, future,
measurements):
"""Invoked when the HTTP request to the DynamoDB has returned and
is responsible for setting the future result or exception based upon
the HTTP response provided.
:param str action: The action that was taken
:param str table: The table name the action was made against
:param int attempt: The attempt number for the action
:param float start: When the request was submitted
:param tornado.concurrent.Future response: The HTTP request future
:param tornado.concurrent.Future future: The action execution future
:param list measurements: The measurement accumulator
"""
self.logger.debug('%s on %s request #%i = %r',
action, table, attempt, response)
now, exception = time.time(), None
try:
future.set_result(self._process_response(response))
except aws_exceptions.ConfigNotFound as error:
exception = exceptions.ConfigNotFound(str(error))
except aws_exceptions.ConfigParserError as error:
exception = exceptions.ConfigParserError(str(error))
except aws_exceptions.NoCredentialsError as error:
exception = exceptions.NoCredentialsError(str(error))
except aws_exceptions.NoProfileError as error:
exception = exceptions.NoProfileError(str(error))
except aws_exceptions.AWSError as error:
exception = exceptions.DynamoDBException(error)
except (ConnectionError, ConnectionResetError, OSError,
aws_exceptions.RequestException, ssl.SSLError,
_select.error, ssl.socket_error, socket.gaierror) as error:
exception = exceptions.RequestException(str(error))
except TimeoutError:
exception = exceptions.TimeoutException()
except httpclient.HTTPError as error:
if error.code == 599:
exception = exceptions.TimeoutException()
else:
exception = exceptions.RequestException(
getattr(getattr(error, 'response', error),
'body', str(error.code)))
except Exception as error:
exception = error
if exception:
future.set_exception(exception)
measurements.append(
Measurement(now, action, table, attempt, max(now, start) - start,
exception.__class__.__name__
if exception else exception))
@staticmethod
def _process_response(response):
"""Process the raw AWS response, returning either the mapped exception
or deserialized response.
:param tornado.concurrent.Future response: The request future
:rtype: dict or list
:raises: sprockets_dynamodb.exceptions.DynamoDBException
"""
error = response.exception()
if error:
if isinstance(error, aws_exceptions.AWSError):
if error.args[1]['type'] in exceptions.MAP:
raise exceptions.MAP[error.args[1]['type']](
error.args[1]['message'])
raise error
http_response = response.result()
if not http_response or not http_response.body:
raise exceptions.DynamoDBException('empty response')
return json.loads(http_response.body.decode('utf-8'))
@staticmethod
def _sleep_duration(attempt):
"""Calculates how long to sleep between exceptions. Returns a value
in seconds.
:param int attempt: The attempt number
:rtype: float
"""
return (float(2 ** attempt) * 100) / 1000
def _unwrap_result(action, result):
"""Unwrap a request response and return only the response data.
:param str action: The action name
:param result: The result of the action
:type: result: list or dict
:rtype: dict | None
"""
if not result:
return
elif action in {'DeleteItem', 'PutItem', 'UpdateItem'}:
return _unwrap_delete_put_update_item(result)
elif action == 'GetItem':
return _unwrap_get_item(result)
elif action == 'Query' or action == 'Scan':
return _unwrap_query_scan(result)
elif action == 'CreateTable':
return _unwrap_create_table(result)
elif action == 'DescribeTable':
return _unwrap_describe_table(result)
return result
def _unwrap_delete_put_update_item(result):
response = {
'Attributes': utils.unmarshall(result['Attributes'] if result else {})
}
if 'ConsumedCapacity' in result:
response['ConsumedCapacity'] = result['ConsumedCapacity']
if 'ItemCollectionMetrics' in result:
response['ItemCollectionMetrics'] = {
'ItemCollectionKey': utils.unmarshall(
result['ItemCollectionMetrics'].get('ItemCollectionKey', {})),
'SizeEstimateRangeGB':
result['ItemCollectionMetrics'].get('SizeEstimateRangeGB',
[None]).pop()
}
return response
def _unwrap_get_item(result):
response = {
'Item': utils.unmarshall(result['Item'] if result else {})
}
if 'ConsumedCapacity' in result:
response['ConsumedCapacity'] = result['ConsumedCapacity']
return response
def _unwrap_query_scan(result):
response = {
'Count': result.get('Count', 0),
'Items': [utils.unmarshall(i) for i in result.get('Items', [])],
'ScannedCount': result.get('ScannedCount', 0)
}
if 'LastEvaluatedKey' in result:
response['LastEvaluatedKey'] = \
utils.unmarshall(result['LastEvaluatedKey'])
if 'ConsumedCapacity' in result:
response['ConsumedCapacity'] = result['ConsumedCapacity']
return response
def _unwrap_create_table(result):
return result['TableDescription']
def _unwrap_describe_table(result):
return result['Table']
def _validate_return_consumed_capacity(value):
if value not in ['INDEXES', 'TOTAL', 'NONE']:
raise ValueError('Invalid return_consumed_capacity value')
def _validate_return_item_collection_metrics(value):
if value not in ['NONE', 'SIZE']:
raise ValueError('Invalid return_item_collection_metrics value')
def _validate_return_values(value):
if value not in ['NONE', 'ALL_NEW', 'ALL_OLD',
'UPDATED_NEW', 'UPDATED_OLD']:
raise ValueError('Invalid return_values value')
def _validate_select(value):
if value not in ['ALL_ATTRIBUTES', 'ALL_PROJECTED_ATTRIBUTES', 'COUNT',
'SPECIFIC_ATTRIBUTES']:
raise ValueError('Invalid select value')