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Stream MQTT Data into Azure Event Hubs

Azure Event Hubs is a real-time managed event streaming platform for data ingestion. EMQX's integration with Azure Event Hub offers users dependable data transport and processing capabilities in high-throughput situations. Azure Event Hubs can serve as a data channel between EMQX and Azure's rich cloud service applications, integrating IoT data into Azure Blob Storage, Azure Stream Analytics, and various applications and services deployed on Azure virtual machines. Currently, EMQX supports Azure Event Hub integration through SASL/PLAIN authentication and endpoints compatible with the Apache Kafka protocol.

This page provides a comprehensive introduction to the data integration between EMQX and Azure Event Hubs with practical instructions on creating and validating the data integration.

How It Works

Azure Event Hubs data bridge is an out-of-the-box feature of EMQX designed to help users seamlessly integrate MQTT data streams with Azure Event Hubs and leverage its rich services and capabilities for IoT application development.


EMQX forwards MQTT data to Azure Event Hubs through the rule engine and data bridge. The complete process is as follows:

  1. IoT Devices Publish Messages: Devices publish telemetry and status data through specific topics, triggering the rule engine.
  2. Rule Engine Processes Messages: Using the built-in rule engine, MQTT messages from specific sources are processed based on topic matching. The rule engine matches corresponding rules and processes messages, such as converting data formats, filtering specific information, or enriching messages with contextual information.
  3. Bridging to Azure Event Hubs: The rule triggers the action of forwarding messages to Azure Event Hubs, allowing easy configuration of data properties, ordering keys, and mapping of MQTT topics to Azure Event Hubs headers. This provides richer context information and order assurance for data integration, enabling flexible IoT data processing.

After MQTT message data is written to Azure Event Hubs, you can perform flexible application development, such as:

  • Real-time Data Processing and Analysis: Utilize powerful Azure Event Hubs data processing and analysis tools and its own streaming capabilities to perform real-time processing and analysis of message data, obtaining valuable insights and decision support.
  • Event-Driven Functionality: Trigger Azure event handling to achieve dynamic and flexible function triggering and processing.
  • Data Storage and Sharing: Transmit message data to Azure Event Hubs storage services for secure storage and management of large volumes of data. This allows you to share and analyze this data with other Azure services to meet various business needs.

Features and Benefits

The data integration between EMQX and Azure Event Hubs can bring the following functions and advantages to your business:

  • High-Performance Massive Message Throughput: EMQX supports connections with a massive number of MQTT clients, with millions of messages per second continuously ingested into Azure Event Hubs. This enables extremely low message transmission and storage latency, and message volume control can be achieved by configuring retention time on Azure Event Hubs.
  • Flexible Data Mapping: Through the configured Azure Event Hubs, flexible mapping can be achieved between MQTT topics and Azure Event Hubs event centers. It also supports the mapping of MQTT user properties to Azure Event Hubs headers, providing richer context information and order assurance for data integration.
  • Elastic Scaling Support: Both EMQX and Azure Event Hubs support elastic scaling and can expand according to the application specifications, easily scaling IoT data sizes from several MBs to several TBs.
  • Rich Ecosystem: By adopting the standard MQTT protocol with the support for various mainstream IoT transmission protocols, EMQX can achieve the connection with various IoT devices. Combined with the support of Azure Event Hubs in Azure Functions, various programming language SDKs, and the Kafka ecosystem, it facilitates seamless IoT data access and processing from devices to the cloud.

These functionalities enhance integration capabilities and flexibility, helping users quickly implement the connection of massive IoT device data with Azure. They enable users to more conveniently harness the data analysis and intelligence capabilities brought by cloud computing, building powerful data-driven applications.

Before You Start

This section describes the preparations you need to complete before you start to create the Azure Event Hub data bridge in the EMQX Dashboard.


Set Up Azure Event Hub

In order to use Azure Event Hub data integration, a Namespace and Event Hub must be set up in the Azure account. The following links to the official documentation provide details on how to do the setup.

Create Azure Event Hubs Data Bridge

This section demonstrates how to create Azure Event Hubs producer data bridge via Dashboard.

  1. Go to EMQX Dashboard, and click Integration -> Data Bridge.

  2. Click Create on the top right corner of the page.

  3. In the Create Data Bridge page, click to select Azure Event Hubs, and then click Next.

  4. Enter a name for the data bridge. The name should be a combination of upper/lower case letters and numbers.

  5. Configure the connection information.

    • Bootstrap Hosts: Enter the Host Name for your Namespace. The default port is 9093. For the other fields set as the actual condition.
    • Connection String: Enter the Connection String for the Namespace. It can be found in the "connection string-primary key" of a Namespace shared access policy. For more information, see Get an Event Hubs connection string.
    • Enable TLS: TLS is enabled by default for connecting to Azure Event Hub. For more information on TLS connection options, see TLS for External Resource Access.
    • Leave other fields by default or specify the value as your business needs.
  6. Configure the data bridge information.

    • Event Hub Name: Enter the name of the Event Hub to be used. Note: Variables are not supported here.
    • Azure Event Hub Headers: Enter a placeholder to be used as headers that will be added to the messages when being published to Azure Event Hub.
    • Azure Event Hub Header value encode mode: Select the value encode mode for the header; optional values are none or json.
    • Extra Azure Event Hub headers: You can click Add to provide more key-value pairs for Azure Event Hub headers.
    • Message Key: Event hub message key. Insert a string here, either a plain string or a string containing placeholders (${var}).
    • Message Value: Event hub message value. Insert a string here, either a plain string or a string containing placeholders (${var}).
    • Message Timestamp: Specify the type of timestamp to be used.
  7. Advanced settings (optional): Set the Max Batch Bytes, Required Acks, and Partition Strategy as your business needs.

  8. Before clicking Create, you can click Test Connection to test that the bridge can connect to the Azure Event Hub server.

  9. Click Create, you'll be offered the option of creating an associated rule.

    For the Azure Event Hub producer data bridge, click Create Rule to create an associated rule. For detailed operating steps, see Create Rule for Azure Event Hub Producer Data Bridge.


    Creating a rule allows Azure Event Hub messages matching the rule to be further transformed and filtered if needed, and then forwarded to other rule actions, like different bridges. Refer to the Rules for more information on creating rules.

Now the Azure Event Hub data bridge should appear in the data bridge list (Integration -> Data Bridge) with Resource Status as Connected.

Create Rule for Azure Event Hubs Producer Data Bridge

  1. Go to EMQX Dashboard, and click Integration -> Rules.

  2. Click Create on the top right corner of the page.

  3. Input, for example, my_rule as the rule ID.

  4. Input the following statement in the SQL Editor if you want to save the MQTT messages under topic t/# to Azure Event Hub.

Note: If you want to specify your own SQL syntax, make sure that you have included all fields required by the data bridge in the SELECT part.

  1. Click the Add Action button, select Forwarding with Data Bridge from the dropdown list and then select the data bridge you just created under Data bridge. Then click the Add button.

  2. Click Create at the page bottom to finish the creation.

Now you have successfully created the data bridge to Azure Event Hub producer data bridge. You can click Integration -> Flows to view the topology. It can be seen that the messages under topic t/# are sent and saved to Azure Event Hub after parsing by rule my_rule.

Test Data Bridge and Rule

To test if the Kafka producer data bridge and rule work as you expected, you can use the MQTTX to simulate a client to publish MQTT messages to EMQX.

  1. Use MQTTX to send messages to topic t/1:
   mqttx pub -i emqx_c -t t/1 -m '{ "msg": "Hello Azure Event Hub" }'
   mqttx pub -i emqx_c -t t/1 -m '{ "msg": "Hello Azure Event Hub" }'
  1. Click the name of the data bridge on the Data Bridge page to view the statistics. Check the running status of the data bridge and there should be one new outgoing message.

  2. Check whether messages are written into the configured Event Hub using any Kafka-compatible consumer. For more information about using the Kafka CLI, see Use the Kafka CLI to Send and Receive Messages to/from Azure Event Hubs for Apache Kafka Ecosystem.