Azure Service Bus

This page describes the usage of the Stream Reactor Azure Service Bus Source Connector.

This Kafka connector is designed to effortlessly ingest records from Azure Service Bus into your Kafka cluster. It leverages Microsoft Azure API to seamlessly transfer data from Service Buses, allowing for their safe transition and safekeeping both payloads and metadata (see Payload support). It provides its user with AT-LEAST-ONCE guarantee as the data is committed (marked as read) in Service Bus once Connector verifies it was successfully committed to designated Kafka topic. Azure Service Bus Source Connector supports both types of Service Buses: Queues and Topics.

Connector Class

io.lenses.streamreactor.connect.azure.servicebus.source.AzureServiceBusSourceConnector

Full Config Example

For more examples see the tutorials.

The following example presents all the mandatory configuration properties for the Service Bus connector. Please note there are also optional parameters listed (link to option reference??). Feel free to tweak the configuration to your requirements.

connector.class=io.lenses.streamreactor.connect.azure.servicebus.source.AzureServiceBusSourceConnector
name=AzureServiceBusSourceConnector
tasks.max=1
connect.servicebus.connection.string="Endpoint=sb://MYNAMESPACE.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=SOME_SHARED_ACCESS_STRING";
connect.servicebus.kcql=INSERT INTO output-topic SELECT * FROM servicebus-queue PROPERTIES('servicebus.type'='QUEUE');

KCQL support

You can specify multiple KCQL statements separated by ; to have the connector sink into multiple topics. However, you can not route the same source to different topics, for this use a separate connector instance.

The following KCQL is supported:

INSERT INTO <your-kafka-topic>
SELECT *
FROM <your-service-bus> 
PROPERTIES(...); 

It allows you to map Service Bus of name <your-service-bus> to Kafka topic of name <your-kafka-topic> using the PROPERTIES specified.

The selection of fields from the Service Bus message is not supported.

Payload support

Azure Service Bus Connector follows specific pattern (Schema) of messages. Please look below for the format of the data transferred to Kafka Topics specified in the KCQL config.

Key Format (Schema)

Field Name	Schema Type	Description
MessageId	String	The message identifier that uniquely identifies the message and its payload.

Payload Format (Schema)

Field Name	Schema Type	Description
deliveryCount	int64	The number of the times this message was delivered to clients.
enqueuedTimeUtc	int64	The time at which this message was enqueued in Azure Service Bus.
contentType	Optional String	The content type of this message.
label	Optional String	The application specific message label.
correlationId	Optional String	The correlation identifier.
messageProperties	Optional String	The map of user application properties of this message.
partitionKey	Optional String	The partition key for sending a message to a partitioned entity.
replyTo	Optional String	The address of an entity to send replies to.
replyToSessionId	Optional String	The session identifier augmenting the ReplyTo address.
deadLetterSource	Optional String	The name of the queue or subscription that this message was enqueued on, before it was deadlettered.
timeToLive	int64	The duration before this message expires.
lockedUntilUtc	Optional int64	The time when the lock of this message expires.
sequenceNumber	Optional int64	The unique number assigned to a message by Azure Service Bus.
sessionId	Optional String	The session identifier for a session-aware entity.
lockToken	Optional String	The lock token for the current message.
messageBody	Optional bytes	The body of this message as a byte array.
getTo	Optional String	The “to” address.

Authentication

You can connect to an Azure Service Bus by passing your connection string in configuration. The connection string can be found in the Shared access policies section of your Azure Portal.

connect.servicebus.connection.string=Endpoint=sb://YOURNAMESPACE.servicebus.windows.net/;SharedAccessKeyName=YOUR_KEYNAME;SharedAccessKey=YOUR_ACCESS_KEY=

Learn more about different methods of connecting to Service Bus on the Azure Website.

Queues & Topics

The Azure Service Bus Connector connects to Service Bus via Microsoft API. In order to smoothly configure your mappings you have to pay attention to PROPERTIES part of your KCQL mappings. There are two cases here: reading from Service Bus of type QUEUE and of type TOPIC. Please refer to the relevant sections below. In case of further questions check Azure Service Bus documentation to learn more about those mechanisms.

Reading from Queues

In order to be reading from the queue there's an additional parameter that you need to pass with your KCQL mapping in the PROPERTIES part. This parameter is servicebus.type and it can take one of two values depending on the type of the service bus: QUEUE or TOPIC. Naturally for Queue we're interested in QUEUE here and we need to pass it.

connect.servicebus.kcql=INSERT INTO kafka-topic SELECT * FROM azure-queue PROPERTIES('servicebus.type'='QUEUE');

This is sufficient to enable you to create the mapping with your queue.

Reading from Topics

In order to be reading from the topic there are two additional parameters that you need to pass with your KCQL mapping in the PROPERTIES part:

1. Parameter servicebus.type which can take one of two values depending on the type of the service bus: QUEUE or TOPIC. For topic we're interested in TOPIC here and we need to pass it.

2. Parameter subscription.name which takes the (case-sensitive) value of a subscription name that you've created for this topic for the connector to use. Please use Azure Portal to create one.

Make sure your subscription exists otherwise you will get a similar error to this

Caused by: com.azure.core.amqp.exception.AmqpException: The messaging entity 'streamreactor:Topic:my-topic|lenses' could not be found. To know more visit https://aka.ms/sbResourceMgrExceptions.

Create the subscription per topic in the Azure Portal.

connect.servicebus.kcql=INSERT INTO kafka-topic SELECT * FROM azure-topic PROPERTIES('servicebus.type'='TOPIC','subscription.name'='subscription1');

This is sufficient to enable you to create the mapping with your topic.

Option Reference

KCQL Properties

Please find below all the necessary KCQL properties:

Name	Description	Type	Default Value
servicebus.type	Specifies Service Bus type: QUEUE or TOPIC	string
subscription.name	Specifies subscription name if Service Bus type is TOPIC	string

Configuration parameters

Please find below all the relevant configuration parameters:

Name	Description	Type	Default Value
connect.servicebus.connection.string	Specifies the Connection String to connect to Service Bus	string
connect.servicebus.kcql	Comma-separated output KCQL queries	string
connect.servicebus.source.task.records.queue.size	Specifies the Queue size between Service Bus Receivers and Kafka	int	5000
connect.servicebus.source.sleep.on.empty.poll.ms	The duration in milliseconds to sleep when no records are returned from the poll. This avoids a tight loop in Connect.	long	250
connect.servicebus.source.complete.retries.max	The maximum number of retries to complete a message.	int	3
connect.servicebus.source.complete.retries.min.backoff.ms	The minimum duration in milliseconds for the first backoff	long	1000
connect.servicebus.source.prefetch.count	The number of messages to prefetch from the Azure Service Bus.	int	2000