Class: StreamManagerClient

aws-greengrass-core-sdk.StreamManager~StreamManagerClient(optsnullable)

Stream manager client

Constructor

new StreamManagerClient(optsnullable)

Constructs a new Stream Manager client. Once connected, onConnectCb will be called and the client can then be used.
Parameters:
Name Type Attributes Description
opts Object <nullable>
 All these options are optional.
Properties
Name Type Attributes Description
port Number
host String
onConnectCb function <nullable>
 Optional callback to be called once the client has connected.
onErrorCb function <nullable>
 Optional, but highly suggested callback to be called when a connection error occurs.
logger Logger <nullable>
Source:
Example

StreamManager Usage

const { StreamManagerClient } = require('aws-greengrass-core-sdk/stream-manager');
const client = new StreamManagerClient();
c.onConnected(async () => {
    // Do work with the client (c) here.
});

Methods

(async) appendMessage(streamName, data) → {Promise.<Number>}

Append a message into the specified message stream. Returns the sequence number of the message if it was successfully appended.
Parameters:
Name Type Description
streamName string The name of the stream to append to.
data Buffer Buffer containing the data to be written.
Source:
Returns:
Type
Promise.<Number>

close()

Close the connection
Source:

(async) createMessageStream(definition) → {Promise.<void>}

Create a message stream with a given definition.
Parameters:
Name Type Description
definition aws-greengrass-core-sdk.StreamManager.MessageStreamDefinition
Source:
Returns:
Type
Promise.<void>

(async) deleteMessageStream(streamName) → {Promise.<void>}

Deletes a message stream based on its name. Nothing is returned if the request succeeds. An error will be thrown if the request fails.
Parameters:
Name Type Description
streamName string The name of the stream to be deleted.
Source:
Returns:
Type
Promise.<void>

(async) describeMessageStream(streamName) → {Promise.<aws-greengrass-core-sdk.StreamManager.MessageStreamInfo>}

Describe a message stream to get metadata including the stream's definition, size, and exporter statuses.
Parameters:
Name Type Description
streamName string The name of the stream to describe
Source:
Returns:
Type
Promise.<aws-greengrass-core-sdk.StreamManager.MessageStreamInfo>

(async) listStreams() → {Promise.<Array.<String>>}

List the streams in StreamManager. Returns a list of their names.
Source:
Returns:
Type
Promise.<Array.<String>>

onConnected(f)

Add a callback for when the client connects.
Parameters:
Name Type Description
f function
Source:

onError(f)

Add a callback for when an error occurs.
Parameters:
Name Type Description
f function
Source:

(async) readMessages(streamName, optionsnullable) → {Promise.<Array.<aws-greengrass-core-sdk.StreamManager.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:
Name Type Attributes Default Description
streamName string The name of the stream to read from.
options aws-greengrass-core-sdk.StreamManager.ReadMessagesOptions <nullable>
 null Options used when reading from the stream of type aws-greengrass-core-sdk.StreamManager.ReadMessagesOptions. Defaults are:
  • desiredStartSequenceNumber: 0
  • minMessageCount: 1
  • maxMessageCount: 1
  • readTimeoutMillis: 0 
    // Where 0 here represents that the server will immediately return the messages
// or an exception if there were not enough messages available.

If desiredStartSequenceNumber 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 desiredStartSequenceNumber.

Source:
Returns:
List of one or more messages.
Type
Promise.<Array.<aws-greengrass-core-sdk.StreamManager.Message>>

(async) updateMessageStream(definition) → {Promise.<void>}

Updates a message stream with the new definition. Minimum version requirements: StreamManager server version 1.1 (or AWS IoT Greengrass Core 1.11.0)
Parameters:
Name Type Description
definition aws-greengrass-core-sdk.StreamManager.MessageStreamDefinition
Source:
Returns:
Type
Promise.<void>