greengrasssdk.stream_manager.streammanagerclient module

Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. SPDX-License-Identifier: Apache-2.0

class greengrasssdk.stream_manager.streammanagerclient.StreamManagerClient(host='127.0.0.1', port=None, connect_timeout=3, request_timeout=60, logger=<Logger StreamManagerClient (WARNING)>)

Bases: object

Creates a client for the Greengrass StreamManager. All parameters are optional.

Parameters:

• host – The host which StreamManager server is running on. Default is localhost.
• port – The port which StreamManager server is running on. Default is found in environment variables.
• connect_timeout – The timeout in seconds for connecting to the server. Default is 3 seconds.
• request_timeout – The timeout in seconds for all operations. Default is 60 seconds.
• logger – A logger to use for client logging. Default is Python’s builtin logger.

Raises:

StreamManagerException and subtypes if authenticating to the server fails.

Raises:

asyncio.TimeoutError if the request times out.

Raises:

ConnectionError if the client is unable to connect to the server.

read_messages(stream_name: str, options: Optional[greengrasssdk.stream_manager.data.ReadMessagesOptions] = None) → List[greengrasssdk.stream_manager.data.Message]

Read message(s) from a chosen stream with options. If no options are specified it will try to read 1 message from the stream.

Parameters:

• stream_name – The name of the stream to read from.
• options –

  (Optional) Options used when reading from the stream of type data.ReadMessagesOptions. Defaults are:

  • desired_start_sequence_number: 0,
  • min_message_count: 1,
  • max_message_count: 1,

  • read_timeout_millis: 0 # Where 0 here represents that the server will immediately return the messages

    # or an exception if there were not enough messages available.

  If desired_start_sequence_number is specified in the options and is less than the current beginning of the stream, returned messages will start at the beginning of the stream and not necessarily the desired_start_sequence_number.

Returns:

List of at least 1 message.

Raises:

StreamManagerException and subtypes based on the precise error.

Raises:

asyncio.TimeoutError if the request times out.

Raises:

ConnectionError if the client is unable to reconnect to the server.

append_message(stream_name: str, data: bytes) → int

Append a message into the specified message stream. Returns the sequence number of the message if it was successfully appended.

Parameters:

• stream_name – The name of the stream to append to.
• data – Bytes type data.

Returns:

Sequence number that the message was assigned if it was appended.

Raises:

StreamManagerException and subtypes based on the precise error.

Raises:

asyncio.TimeoutError if the request times out.

Raises:

ConnectionError if the client is unable to reconnect to the server.

create_message_stream(definition: greengrasssdk.stream_manager.data.MessageStreamDefinition) → None

Create a message stream with a given definition.

Parameters:definition – MessageStreamDefinition definition object. Returns:Nothing is returned if the request succeeds. Raises:StreamManagerException and subtypes based on the precise error. Raises:asyncio.TimeoutError if the request times out. Raises:ConnectionError if the client is unable to reconnect to the server.

delete_message_stream(stream_name: str) → None

Deletes a message stream based on its name. Nothing is returned if the request succeeds, a subtype of StreamManagerException will be raised if an error occurs.

Parameters:stream_name – The name of the stream to be deleted. Returns:Nothing is returned if the request succeeds. Raises:StreamManagerException and subtypes based on the precise error. Raises:asyncio.TimeoutError if the request times out. Raises:ConnectionError if the client is unable to reconnect to the server.

update_message_stream(definition: greengrasssdk.stream_manager.data.MessageStreamDefinition) → None

Updates a message stream based on a given definition. Minimum version requirements: StreamManager server version 1.1 (or AWS IoT Greengrass Core 1.11.0)

Parameters:definition – class:MessageStreamDefinition definition object. Returns:Nothing is returned if the request succeeds. Raises:StreamManagerException and subtypes based on the precise error. Raises:asyncio.TimeoutError if the request times out. Raises:ConnectionError if the client is unable to reconnect to the server.

list_streams() → List[str]

List the streams in StreamManager. Returns a list of their names.

Returns:List of stream names. Raises:StreamManagerException and subtypes based on the precise error. Raises:asyncio.TimeoutError if the request times out. Raises:ConnectionError if the client is unable to reconnect to the server.

describe_message_stream(stream_name: str) → greengrasssdk.stream_manager.data.MessageStreamInfo

Describe a message stream to get metadata including the stream’s definition, size, and exporter statuses.

Parameters:stream_name – The name of the stream to describe. Returns:MessageStreamInfo type containing the stream information. Raises:StreamManagerException and subtypes based on the precise error. Raises:asyncio.TimeoutError if the request times out. Raises:ConnectionError if the client is unable to reconnect to the server.

close()

Call to shutdown the client and close all existing connections. Once a client is closed it cannot be reused.

Raises:StreamManagerException and subtypes based on the precise error.