node-red-node-tdengine/locales/en-US/tdengine-consumer.html

The official plugin developed by TDengine for Node-RED.

<script type="text/html" data-help-name="tdengine-consumer">
    <p><b>TDengine Subscription Consumer Node</b></p>
    <p>This node automatically connects to a specified TDengine server and subscribes to given topics.</p>

    <h3>Key Features</h3>
    <ul>
        <li>Support for both local and cloud service data sources</li>
        <li>Flexible configuration of subscription properties</li>
        <li>Support subscribing to multiple topics simultaneously.</li>
        <li>Automatic saving of consumption progress</li>
        <li>Automatic reconnection after server disconnection</li>
    </ul>

    <h3>Node Status</h3>
    <ul>
        <li>Grey: Connecting</li>
        <li>Green: Operational</li>
        <li>Red: Malfunction</li>
    </ul>
    
    <h3>Configuration:</h3>
    <ul>
        <li><b>Name:</b> Optional name for the node in the flow editor.</li>        
        <li><b>Subscription Server:</b> WebSocket address of the subscription server.
            <p>Local deployment format: <code>ws://host:port</code>.</p>
            <ul>
              <li>host: TDengine server name or IP address</li>
              <li>port: Port number, default <code>6041</code></li> 
            </ul>  
            <p>Cloud service format: <code>wss://gw.us-west-2.aws.cloud.tdengine.com?token=0df909...</code><p>
            <ul>
              <li>host: gw.us-west-2.aws.cloud.tdengine.com</li>
              <li>token: Obtain from <a href="https://cloud.tdengine.com/">Cloud Service Website</a></li> 
            </ul> 
        </li>
        <li><b>Username:</b> Server username (Note: Cloud authorization is in TOKEN, not required)</li>
        <li><b>Password:</b> Server password (Note: Cloud authorization is in TOKEN, not required)</li>
        <li><b>Subscription Topics:</b> Topic names to subscribe to (comma separated)</li>
        <li><b>Consumer Group ID:</b> Consumer group ID, default <code>group1</code></li>
        <li><b>Client ID:</b> Unique client identifier for this consumer</li>
        <li><b>Initial Offset:</b>
            <ul>
                <li><code>earliest</code>: Subscribe from beginning</li>
                <li><code>latest</code>: Subscribe only from latest data</li>
            </ul>
        </li>
        <li><b>Poll Timeout (ms):</b> Wait time for data consumption, default <code>5000</code></li>
        <li><b>Auto Commit:</b> Enable automatic offset committing, default <code>true</code></li>
        <li><b>Commit Interval (ms):</b> Auto-commit interval, default <code>5000</code></li>
    </ul>

    <h3>Input Format</h3>
    <p>Input node (no input)</p>

    <h3>Output Format</h3>
    <p>payload outputs array of objects where properties correspond to column names:</p>
    <p>
        <a href="https://docs.tdengine.com/tdengine-reference/client-libraries/node/#data-type-mapping" target="_blank">
            TDengine NodeJS Connector Type Mapping
        </a>
    </p>

<pre><code class="json">{
  topic: Subscription topic,
  database: Database name,
  vgroup_id: Data partition,
  precision: Database precision
  payload: [{ 
    column_name1: value1,
    column_name2: value2,
    ...
  },
  ...
  ],
}</code></pre>

    <h3>Error Handling</h3>
    <ul>
        <li>Automatically throws exceptions on failure (no msg passed downstream)</li>
        <li>Use Catch node to handle errors</li>
        <li>Error logs include complete error objects and TDengine error codes</li>
        <li>Node status changes to <code>Malfunction</code> on errors</li>
    </ul>

    <h3>Log Configuration</h3>
    Log levels follow Node-RED settings:
<pre><code class="json">// settings.js
logging: {
level: "info"  
}</code></pre>
    <ul>
        <li>Log format: [Timestamp] [Node Name] [Message]</li>
        <li>Capitalized messages indicate new operation phases</li>
        <li>Supported levels: error, warn, info, debug</li>
    </ul>

    <h3>Usage Example</h3>
    <div class="node-help-examples">
        <p><b>Subscription output for topic1:</b></p>

        <pre><code class="json">{
  topic: 'topic1',
  payload: [{ 
    ts: 1749281716809,
    current: 1,
    voltage: 2, 
    phase:   4 
  } ],
  database: 'test',
  vgroup_id: 4,
  precision: 0
}</code></pre>
</div>

<h3>About TDengine</h3>
<a href="https://www.tdengine.com">TDengine</a> is a time-series database purpose-built for Industry 4.0 and Industrial IoT. It enables real-time ingestion, storage, analysis, and distribution of petabytes of data per day, generated by billions of sensors and data collectors. With TDengine making big data accessible, valuable, and affordable, digital transformation has never been easier.
<p>&nbsp;</p>
</script>