API Documentation

class sprockets_dynamodb.client.Client(**kwargs)[source]

Asynchronous DynamoDB Client

Parameters:
  • region (str) – AWS region to send requests to
  • access_key (str) – AWS access key. If unspecified, this defaults to the AWS_ACCESS_KEY_ID environment variable and will fall back to using the AWS CLI credentials file. See tornado_aws.client.AsyncAWSClient for more details.
  • secret_key (str) – AWS secret used to secure API calls. If unspecified, this defaults to the AWS_SECRET_ACCESS_KEY environment variable and will fall back to using the AWS CLI credentials as described in tornado_aws.client.AsyncAWSClient.
  • profile (str) – optional profile to use in AWS API calls. If unspecified, this defaults to the AWS_DEFAULT_PROFILE environment variable or default if unset.
  • endpoint (str) – DynamoDB endpoint to contact. If unspecified, the default is determined by the region.
  • max_clients (int) – optional maximum number of HTTP requests that may be performed in parallel.
  • max_retries (int) – Maximum number of times to retry a request when if fails under certain conditions. Can also be set with the DYNAMODB_MAX_RETRIES environment variable.
  • instrumentation_callback (method) – A method that is invoked with a list of measurements that were collected during the execution of an individual action.
  • on_error_callback (method) – 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:

Create an instance of this class to interact with a DynamoDB server. A tornado_aws.client.AsyncAWSClient instance implements the AWS API wrapping and this class provides the DynamoDB specifics.

batch_get_item()[source]

Invoke the BatchGetItem function.

batch_write_item()[source]

Invoke the BatchWriteItem function.

create_table(table_definition)[source]

Invoke the CreateTable function.

Parameters:table_definition (dict) – description of the table to create according to CreateTable
Return type:tornado.concurrent.Future
delete_item(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)[source]

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.

Parameters:
  • table_name (str) – The name of the table from which to delete the item.
  • key_dict (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.
  • condition_expression (str) – A condition that must be satisfied in order for a conditional DeleteItem to succeed. See the AWS documentation for ConditionExpression for more information.
  • expression_attribute_names (dict) – One or more substitution tokens for attribute names in an expression. See the AWS documentation for ExpressionAttributeNames for more information.
  • expression_attribute_values (dict) – One or more values that can be substituted in an expression. See the AWS documentation for ExpressionAttributeValues for more information.
  • return_consumed_capacity (str) – Determines the level of detail about provisioned throughput consumption that is returned in the response. See the AWS documentation for ReturnConsumedCapacity for more information.
  • return_item_collection_metrics (str) – Determines whether item collection metrics are returned.
  • return_values (str) – Return the item attributes as they appeared before they were deleted.
delete_table(table_name)[source]

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 ResourceInUse exception is raised. If the specified table does not exist, a ResourceNotFound exception is raised. If table is already in the DELETING state, no error is returned.

Parameters:table_name (str) – name of the table to describe.
Return type:tornado.concurrent.Future
describe_table(table_name)[source]

Invoke the DescribeTable function.

Parameters:table_name (str) – name of the table to describe.
Return type:tornado.concurrent.Future
execute(*args, **kwargs)[source]

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.

Parameters:
  • action (str) – DynamoDB action to invoke
  • parameters (dict) – parameters to send into the action
Return type:

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:DynamoDBException ConfigNotFound NoCredentialsError NoProfileError TimeoutException RequestException InternalFailure LimitExceeded MissingParameter OptInRequired ResourceInUse RequestExpired ResourceNotFound ServiceUnavailable ThroughputExceeded ValidationException
get_item(table_name, key_dict, consistent_read=False, expression_attribute_names=None, projection_expression=None, return_consumed_capacity=None)[source]

Invoke the GetItem function.

Parameters:
  • table_name (str) – table to retrieve the item from
  • key_dict (dict) – key to use for retrieval. This will be marshalled for you so a native dict works.
  • consistent_read (bool) – 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.
  • expression_attribute_names (dict) – One or more substitution tokens for attribute names in an expression.
  • projection_expression (str) – 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.
  • return_consumed_capacity (str) –

    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.
Return type:

tornado.concurrent.Future
list_tables(exclusive_start_table_name=None, limit=None)[source]

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.

Parameters:
  • exclusive_start_table_name (str) – 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.
  • limit (int) – A maximum number of table names to return. If this parameter is not specified, the limit is 100.
put_item(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)[source]

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.

Parameters:
  • table_name (str) – The table to put the item to
  • item (dict) –

    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.

  • condition_expression (str) –

    A condition that must be satisfied in order for a conditional PutItem operation to succeed. See the AWS documentation for ConditionExpression for more information.

  • expression_attribute_names (dict) –

    One or more substitution tokens for attribute names in an expression. See the AWS documentation for ExpressionAttributeNames for more information.

  • expression_attribute_values (dict) –

    One or more values that can be substituted in an expression. See the AWS documentation for ExpressionAttributeValues for more information.

  • return_consumed_capacity (str) – Determines the level of detail about provisioned throughput consumption that is returned in the response. Should be None or one of INDEXES or TOTAL
  • return_item_collection_metrics (str) – Determines whether item collection metrics are returned.
  • return_values (str) – Use ReturnValues if you want to get the item attributes as they appeared before they were updated with the PutItem request.
Return type:

tornado.concurrent.Future
query(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)[source]

A Query operation uses the primary key of a table or a secondary index to directly access items from that table or index.

Parameters:
  • table_name (str) – The name of the table containing the requested items.
  • consistent_read (bool) – 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 ValidationException.
  • exclusive_start_key (dict) – 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.
  • expression_attribute_names (dict) – One or more substitution tokens for attribute names in an expression.
  • expression_attribute_values (dict) – One or more values that can be substituted in an expression.
  • filter_expression (str) – 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 in the Amazon DynamoDB Developer Guide.
  • projection_expression (str) –
  • index_name (str) – 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.
  • limit (int) – 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 in the Amazon DynamoDB Developer Guide.
  • return_consumed_capacity (str) –

    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.
  • scan_index_forward (bool) – 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.
  • select (str) –

    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.
Return type:

dict
scan(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)[source]

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 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.

Return type:dict
set_error_callback(callback)[source]

Assign a method to invoke when a request has encountered an unrecoverable error in an action execution.

Parameters:callback (method) – The method to invoke
set_instrumentation_callback(callback)[source]

Assign a method to invoke when a request has completed gathering measurements.

Parameters:callback (method) – The method to invoke
update_item(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)[source]

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).

Parameters:
  • table_name (str) – The name of the table that contains the item to update
  • key_dict (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.
  • condition_expression (str) – 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.
  • update_expression (str) – An expression that defines one or more attributes to be updated, the action to be performed on them, and new value(s) for them.
  • expression_attribute_names (dict) – One or more substitution tokens for attribute names in an expression.
  • expression_attribute_values (dict) – One or more values that can be substituted in an expression.
  • return_consumed_capacity (str) –

    Determines the level of detail about provisioned throughput consumption that is returned in the response. See the AWS documentation for ReturnConsumedCapacity for more information.

  • return_item_collection_metrics (str) – Determines whether item collection metrics are returned.
  • return_values (str) – 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
Return type:

tornado.concurrent.Future
update_table(table_definition)[source]

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.

Parameters:table_definition (dict) – description of the table to update according to UpdateTable
Return type:tornado.concurrent.Future