Ingest MQTT Data into RabbitMQ

RabbitMQ is a widely used open-source message broker that implements the Advanced Message Queuing Protocol (AMQP). It provides a robust and scalable platform for messaging between distributed systems. EMQX Platform supports integration with RabbitMQ, allowing you to forward MQTT messages and events to RabbitMQ. It also enables consuming data from the RabbitMQ Server and publishing it to specific topics in the EMQX Platform, achieving message delivery from RabbitMQ to MQTT.

This page provides a detailed overview of the data integration between EMQX Platform and RabbitMQ, with practical instructions on creating and validating the data integration.

How It Works

The RabbitMQ data integration is an out-of-the-box feature in EMQX Platform designed to bridge the gap between MQTT-based IoT data and RabbitMQ's powerful message queue processing capabilities. With a built-in rule engine component, the integration simplifies the process of ingesting data from EMQX Platform to RabbitMQ for storage and management, eliminating the need for complex coding.

The diagram below illustrates a typical architecture of data integration between EMQX Platform and RabbitMQ:

Ingesting MQTT data into RabbitMQ works as follows:

1. Message publication and reception: Industrial IoT devices establish successful connections to EMQX Platform through the MQTT protocol and publish real-time MQTT data to EMQX Platform. When EMQX Platform receives these messages, it initiates the matching process within its rules engine.
2. Message data processing: When a message arrives, it passes through the rule engine and is then processed by the rule defined in EMQX Platform. The rules, based on predefined criteria, determine which messages need to be routed to RabbitMQ. If any rules specify payload transformations, those transformations are applied, such as converting data formats, filtering out specific information, or enriching the payload with additional context.
3. Message ingestion into RabbitMQ: When the rule has finished processing the message, it triggers an action of forwarding the messages to RabbitMQ. Processed messages will be seamlessly written into RabbitMQ.
4. Data persistence and Utilization: RabbitMQ stores the messages in queues and delivers them to the appropriate consumers. The messages can be consumed by other applications or services for further processing, such as data analysis, visualization, and storage.

Features and Benefits

The data integration with RabbitMQ brings the following features and advantages to your business:

• Reliable IoT Data Message Delivery: EMQX Platform ensures reliable connections and message delivery from devices to the cloud, while RabbitMQ handles message persistence and reliable delivery across different services, ensuring data reliability throughout various processes.
• MQTT Message Transformation: Using the rule engine, EMQX Platform can filter and transform MQTT messages. Messages can undergo data extraction, filtering, enrichment, and transformation before being sent to RabbitMQ.
• Flexible Message Mapping: RabbitMQ data integration supports flexible mapping of MQTT topics to RabbitMQ Routing Key and Exchange, allowing seamless integration between MQTT and RabbitMQ.
• High Availability and Cluster Support: EMQX Platform and RabbitMQ both support the construction of highly available message broker clusters, ensuring that the system can continue to provide services even in the event of node failures. Leveraging the cluster capabilities also provides excellent scalability.
• Processing Capabilities in High-Throughput Scenarios: RabbitMQ data integration supports both synchronous and asynchronous write modes, allowing for a flexible balance between latency and throughput according to different scenarios.

Before You Start

This section describes the preparations you need to complete before you start to create the RabbitMQ data integration, including how to create a RabbitMQ server and create RabbitMQ test exchange and queue.

Prerequisites

• Knowledge about data integration
• Knowledge about EMQX Platform data integration rules
• Basic knowledge of UNIX terminal and commands

Set up Network

Before you start, you need to create a deployment (EMQX cluster) on the EMQX Platform and configure the network.

• For Dedicated deployment users: First, create a VPC Peering Connection. After establishing the peering connection, you can log in to the Platform Console via the internal network IP to access the target connector. Alternatively, set up a NAT Gateway to access the target connector through a public IP.
• For BYOC (Bring Your Own Cloud) deployment users: Establish a peering connection between the VPC where BYOC is deployed and the VPC where the target connector is located. After creating the peering connection, you can access the target connector via the internal network IP. If you need to access resources via a public IP address, configure a NAT gateway for the VPC where BYOC is deployed in the public cloud console.

Start a RabbitMQ Server

This section introduces how to start a RabbitMQ server using Docker.

Run the following command to start a RabbitMQ server with the management plugin enabled. The management plugin allows you to inspect RabbitMQ with a web interface.

docker run -it --rm --name rabbitmq -p 5672:5672 -p 15672:15672 rabbitmq:3.11-management

You can find more information about running RabbitMQ in Docker on Docker Hub.

Create an Exchange and Queue for Message Receiving

After the RabbitMQ server is started, you can use the RabbitMQ Management Web Interface to create a test exchange and a queue for receiving messages forwarded from EMQX Platform. You can skip this section if you already have an exchange and queue to test with.

1. Open your web browser and navigate to http://{ip address}:15672/ to access the RabbitMQ Management Web Interface. On the login page, enter the default credentials and click Login.

   • Username: guest
   • Password: guest

2. Click the Exchanges tab in the top menu. Unfold Add a new exchange, and input the following information:

   • Name: Type test_exchange
   • Type: Select direct from the drop-down list
   • Durability: Select Durable to make the exchange persistent, that is the queue exists after the RabbitMQ server is restarted.
   • Auto delete: No
   • Internal: No
   • Arguments: Leave empty

3. Click the Add exchange button to create the test exchange.

4. Click the Queues tab in the top menu. Unfold Add a new queue, and input the following information:

   • Type: Default for virtual host
   • Name: Type test_queue
   • Durability: Select Durable to make the queue persistent,
   • Arguments: Leave empty

5. Click the Add queue button to create the test queue. The new test_queue should appear in All queues section.

6. Click the queue name test_queue to open its details page. Unfold Bindings. In the Add binding to this queue section, input the following information:

   • From exchange: Type test_exchange
   • Routing key: Type test_routing_key
   • Arguments: Leave empty

7. Click the Bind button to bind the test_queue to the test_exchange with the specified routing key.

Create a Connector

Before creating data integration rules, you need to first create a RabbitMQ connector to access the RabbitMQ server.

1. Go to your deployment. Click Data Integration from the left-navigation menu. If it is the first time for you to create a connector, select RabbitMQ under the Data Forward category. If you have already created connectors, select New Connector and then select RabbitMQ under the Data Forward category.

2. Connector Name: The system will automatically generate a connector name.

3. Enter the connection information:

   • Server: Enter localhost or the actual hostname/IP if the RabbitMQ server is running remotely.
   • Port: Enter 5672 or the actual port if different.
   • Username: Enter guest.
   • Password: Enter guest.
   • Virtual Host: Enter RabbitMQ virtual host; / by default.
   • Enable TLS: If you want to establish an encrypted connection, click the toggle switch.
   • Configure advanced settings according to your business needs (optional).

4. Click the Test button. If the Pulsar service is accessible, a prompt indicating connector available will be returned.

5. Click the New button to complete the creation.

Create a Producer Rule

This section demonstrates how to create a RabbitMQ Producer Rule and add an action to the rule via the EMQX Platform Console.

1. Click New Rule in the Rules area or click the New Rule icon in the Actions column of the connector you just created.

2. Set the rules in the SQL Editor based on the feature to use, Our goal is to trigger the engine when the client sends a temperature and humidity message to the temp_hum/emqx topic. Here you need a certain process of SQL:

    SELECT
     timestamp, clientid, payload
    FROM
      "temp_hum/emqx"

   TIP

   If you are a beginner user, click SQL Examples and Try It Out to learn and test the SQL rule.

3. Click Next to add an action.

4. Select the connector you just created from the Connector dropdown box.

5. Configure the information for publishing messages from the EMQX Platform to the RabbitMQ service:

   • Exchange: Enter test_exchange created before, which means messages will be published to this exchange.

   • Routing Key: Enter test_routing_key created before, which is the RabbitMQ routing key to be used when publishing messages.

   • In the Message Delivery Mode dropdown, select between non_persistent and persistent:

     • non_persistent (default): Messages are not persisted to disk and may be lost if RabbitMQ restarts or crashes.

     • persistent: Messages are persisted to disk, providing durability in case RabbitMQ restarts or crashes.

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     You may also need to set the queue and exchange as durable to prevent messages from being lost in case RabbitMQ is restarted. See the RabbitMQ documentation for more information.

   • Payload Template: The default value is an empty string, meaning the message payload will be forwarded as JSON-formatted text to RabbitMQ without modification.

     You can also define a custom message payload format using placeholders within the template to dynamically include data from the incoming MQTT messages. For example, if you want to include the MQTT message payload and its timestamp in the RabbitMQ message, you can use the following template:

     {"payload": "${payload}", "timestamp": ${timestamp}}

     This template will produce a JSON-formatted message containing the payload and timestamp of the incoming MQTT message. ${payload} and ${timestamp} are placeholders and will be replaced by the actual values from the message when it is forwarded to the RabbitMQ server.

   • Wait for Publish Confirmations: Enabled by default to ensure that messages are successfully published to RabbitMQ.

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     With this option enabled RabbitMQ broker acknowledges the receipt of a published message before considering it successfully published, which improves the reliability of your message delivery.

6. Expand Advanced Settings to configure Sync/Async mode, queue and batch, and other parameters as appropriate Advanced Settings Options (optional)

7. Click the Confirm button to complete the rule creation.

8. In the Successful new rule pop-up, click Back to Rules, thus completing the entire data integration configuration chain.

Test the Producer Rule

You are recommended to use MQTTX to simulate temperature and humidity data reporting, but you can also use any other client.

1. Use MQTTX to connect to the deployment and send messages to the following Topic.

   • topic: temp_hum/emqx

   • client id: test_client

   • payload:

     {
       "temp": "27.5",
       "hum": "41.8"
     }

2. If the action and rule are created successfully, a message should have been published to the specified exchange in the RabbitMQ server with the specified routing key. Visit the RabbitMQ Management Console at http://{ip address}:15672 and navigate to the Queues section.

3. Verify that the message has been routed to the appropriate queue(s). Click the queue to see details and then click the Get Message(s) button to see the detailed message contents.

   • payload:

     {"payload":
      "{
      "temp": "27.5",
      "hum": "41.8"
       }",
       "timestamp": 1711333401673
     }

Create a RabbitMQ Source Rule

This section demonstrates how to create a RabbitMQ Source rule and add a republish action to the rule for forwarding the message consumed from the RabbitMQ source to the EMQX Platform and publishing to the topic t/1.

1. Click New Rule in the Rules area or click the New Rule icon in the Actions column of the connector you just created.

2. Enter the rule ID my_rule_source.

3. Configure the source (Data Inputs) that triggers the rule. Click the Actions (Source) tab on the right side of the page, and click New Action (Source) to create a RabbitMQ Source.

4. In the slided pane, select RabbitMQ (Source) for the source type and click Next to enter the configuration step.

5. Select the previously created my-rabbitmq connector from the Connector dropdown box. You can also click the create button next to the dropdown box to quickly create a new connector in the popup, with required configuration parameters referring to Create a Connector.

6. Configure the Source information to complete the setup for consuming messages from RabbitMQ to EMQX Platform:

   • Queue: Fill in the queue name message-send previously created in RabbitMQ.
   • No Ack: Select according to the situation, whether to consume messages from RabbitMQ using the no_ack mode. Enabling no_ack mode means RabbitMQ does not wait for a message to be acknowledged after delivering it to a consumer, so it is removed from the queue immediately, even if the consumer has not processed it successfully.
   • Wait for Publish Confirmations: Specify whether to wait for RabbitMQ to confirm messages when using message publisher acknowledgments.

7. Advanced settings (optional): Use the default values.

8. Click the Confirm button to complete the creation of the Source, adding it to the rule data inputs. At the same time, you can see the rule SQL has changed to:

   sql

   SELECT
   *
   FROM
   "$bridges/rabbitmq:my-rabbitmq-source"

   The rule SQL can access the following fields from the RabbitMQ Source, and you can adjust the SQL for data processing operations. The default SQL can be used here.

   Field Name	Description
   payload	The content of the RabbitMQ message
   event	The event topic, formatted as $bridges/rabbitmq:<source name>
   metadata	Rule ID information
   timestamp	The timestamp when the message arrives at EMQX
   node	The name of the EMQX node where the message arrives
   queue	The name of the queue from which the message was consumed
   exchange	The exchange through which the message was routed
   routing_key	The routing key used to route the message from the exchange to the queue

9. Click Next, and create the output action.

10. In the new output action, select Republish.

11. Fill in the message republish configuration:

    • Topic: The topic to publish to MQTT, enter t/1 here.
    • QoS: Select 0, 1, 2, or ${qos}, or enter a placeholder to set QoS from other fields. Selecting ${qos} here means to follow the original message's QoS.
    • Retain: Select true or false. Determine whether to publish the message as a retained message, placeholders can also be entered to set the retain message flag from other fields. In this example, select false.
    • Payload: Set a template for generating the forwarded message payload. Leaving it blank by default means forwarding the rule output result. Here you can enter ${payload} to indicate forwarding Payload only.
    • MQTT 5.0 Message Properties: Disabled by default. For detailed settings, see Add Republish Action.

12. Use default settings for other configurations, and click the Confirm button to complete the creation of the output action.

After successful creation, you will return to the New Rule page. In the Rules list, you can see the newly created rule. Republish actions are currently not displayed in the Actions (Source). If needed, click the rule edit button, and you can see the republish output action at the bottom of the rule settings.

Test the RabbitMQ Source Rule

1. Use MQTTX CLI to subscribe to the topic t/1:

   bash

   mqttx sub -t t/1

2. You can produce a message in RabbitMQ using the following command:

   bash

   rabbitmqadmin --username=guest --password=guest \
        publish routing_key=message-send \
        payload="{ \"msg\": \"Hello EMQX\"}"

   • publish is the command used to publish a message.
   • routing_key=message-send option is used to set the message's routing key. In this example, the queue's name is used as the routing key.
   • payload="{ \"msg\": \"Hello EMQX\"}" option is used to set the content of the message.

   Alternatively, you can also publish a message from the RabbitMQ management interface:

   1. Click the Queues tab in the top menu bar.
   2. Click message-send in the Name column to open its details page.
   3. Expand Publish message, enter "Hello EMQX" in the Payload box, and then click the Publish message button.

3. You will see the output in MQTTX:

   [2024-2-23] [16:59:28] › payload: {"payload":{"msg":"Hello EMQX"},"event":"$bridges/rabbitmq:my-rabbitmq-source","metadata":{"rule_id":"rule_0ly1"},"timestamp":1708678768449,"node":"emqx@127.0.0.1"}