EMQX

EMQX is an open-source, highly scalable, and distributed MQTT(Message Queuing Telemetry Transport) broker designed for IoT applications. This section explains how to configure EMQX to write data into KWDB using KWDB's RESTful API.

The integration enables EMQX to transform incoming MQTT messages into HTTP requests containing INSERT statements and forward them to KWDB's Insert API. Once configured, data from IoT devices will automatically flow from EMQX to your KWDB tables. For more information on the Insert endpoint, see Insert Endpoint.

Configure EMQX

Prerequisites

Before configuring the integration, ensure you have:

• EMQX Setup:

  • Installed EMQX (version 5.0.19 or compatible)
  • Started the EMQX service For instructions, see EMQX Documentation.

• KWDB Setup:

  • Installed KWDB and created a database
  • Created a user with appropriate privileges on tables or higher
  • Created the target table where MQTT data will be inserted (the user must have INSERT privilege on this table)

• Authentication Token

  Generate an authentication token for KWDB API access using:

  curl -L -k -H "Authorization: Basic <base64(user:password)>" -X GET <node_ip>:8080/restapi/login
  

  Where:

  • Base64(user:password): Base64-encoded username and password
  • node_ip: The IP address of your KWDB node

  Note

  By default, the generated token is valid for 60 minutes. For data report intervals:

  • Less than 60 minutes: The system automatically extends the token.
  • Greater than 60 minutes: You must generate a new token before expiration or use SET CLUSTER SETTING server.rest.timeout=<value> to set a custom expiration period. The configurable range is [1, 2^63-1] minutes.

Steps

The following steps uses EMQX version 5.0.19. UI elements and configuration steps may vary in other versions.

1. Create a webhook data bridge:

   1. Log in to the EMQX Dashboard.
      • Default URL: http://<emqx_host>:18083
      • Default credentials: Username admin, Password public
   2. Navigate to Data Integration > Data Bridge in the left sidebar.
   3. Click Create and select Webhook as the bridge type.
   4. Enter a name for your data bridge (e.g., "KWDB-Integration").

2. Configure the webhook settings:

   1. Set the HTTP method to POST.

   2. Enter the KWDB Insert API endpoint: http://<kaiwudb_host>:8080/restapi/insert.

   3. Configure the Headers:

      • Add header Content-Type with value application/json.
      • Add header Authorization with value of your token.

   4. In the Body section, enter the SQL template for inserting data:

      INSERT INTO my_database.my_table VALUES (now(), ${payload.temperature}, ${payload.humidity}, ${payload.volume}, 'a'"
      

   5. Click Create to save the data bridge.

3. Create a rule for processing MQTT messages:

   1. Navigate to Data Integration > Rules in the left sidebar.
   2. Click Create.
   3. In the SQL Editor, enter a rule to select and process incoming MQTT messages.
   4. Click Add Action.
   5. Select Forward using Data Bridge as the action type.
   6. Choose the data bridge you created earlier from the dropdown.
   7. Click Add to add the action.

   For more information on EMQX rules and examples, see EMQX Documentation.