Kafka
Apache Kafka is an open-source distributed event streaming platform with applications in many industries. Kafka runs as a cluster of one or more Kafka servers which communicate with clients. Clients can act as consumers by receiving messages from Kafka servers or as producers by publishing messages. Kafka messages (also known as events or records in the documentation) are categorized by topics. Each message within a topic can have an optional key, used for message organization and partitioning.
The Kafka Device Driver is a client which can serve as both a consumer and producer, allowing Iotellect Server to exchange messages with Kafka servers.
Driver Information
Driver Plugin ID: | com.tibbo.linkserver.plugin.device.kafka |
Global Settings
None defined.
User Level Settings
None defined.
Device Account Properties
Connection Properties
Connection settings define how Iotellect Server will connect to Kafka instances, and which topics will be polled. Here is a list of available connection properties:
Property | Description |
Broker Addresses | Data table specifying the details of the Kafka broker for the client's initial connection.
|
Topics | List of topics to which the device will be subscribed. |
Max Poll Records | The maximum number of records to be returned per poll request. |
Poll Duration | Maximum amount of time to wait for a response during a poll request. |
Auto Commit Interval | The amount of time which that the consumer offsets will be auto-committed to Kafka. |
Consumer Group ID | Identifier of the Kafka consumer group that this device belongs to. |
Device Assets
Assets are not supported by the driver.
Device Settings
The Kafka Device Driver creates one Device setting variable:
Variable Name | Variable Description | Comments |
messageCount | Message Count | Count of received messages. Value is updated every synchronization. Reconnection resets count to zero. |
Device Operations
Publish Text Message
This function allows the device to act as a message producer by writing a message to a topic.
The format of the function input parameters has the following fields:
Name | Type | Description |
topic | String | Indicates the topic where the message should be written. |
textMessage | String | Value of the message. |
key | String | Key value for the message. If left |
The function has no output parameters.
Device Events
Message
Fired when Iotellect Server receives a message to one of the topics listed in connection properties.
Event Name | message |
Permissions: | Accessible at Observer permission level |
Records: | 1 |
Record Format:
Field Name | Field Type | Notes |
topic | String | The topic of the message. |
key | String | The key of the received message. |
textMessage | String | Text of the received message. |
partition | String | Indicates which partition the message is stored in. |
offset | String | Used to maintain the current position of the consumer and ensure the same message is not received twice. |
key | String | Used for message organization and partitioning within a topic. |
Synchronization Details
Kafka driver polls the Kafka cluster and subscribes to the topics indicated in connection properties.
This driver will mark the device Offline if a connection cannot be established with Kafka broker.
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