142 lines
5.3 KiB
Markdown
142 lines
5.3 KiB
Markdown
---
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title: EMQX Broker writing
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sidebar_label: EMQX Broker
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description: This document describes how to integrate TDengine with the EMQX broker.
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---
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MQTT is a popular IoT data transfer protocol. [EMQX](https://github.com/emqx/emqx) is an open-source MQTT Broker software. You can write MQTT data directly to TDengine without any code. You only need to setup "rules" in EMQX Dashboard to create a simple configuration. EMQX supports saving data to TDengine by sending data to a web service and provides a native TDengine driver for direct saving in the Enterprise Edition. Please refer to the [EMQX official documentation](https://www.emqx.io/docs/en/v4.4/rule/rule-engine.html) for details on how to use it.).
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## Prerequisites
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The following preparations are required for EMQX to add TDengine data sources correctly.
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- The TDengine cluster is deployed and working properly
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- taosAdapter is installed and running properly. Please refer to the [taosAdapter manual](../../reference/taosadapter) for details.
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- If you use the emulated writers described later, you need to install the appropriate version of Node.js. V12 is recommended.
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## Install and start EMQX
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Depending on the current operating system, users can download the installation package from the [EMQX official website](https://www.emqx.io/downloads) and execute the installation. After installation, use `sudo emqx start` or `sudo systemctl start emqx` to start the EMQX service.
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Note: this chapter is based on EMQX v4.4.5. Other version of EMQX probably change its user interface, configuration methods or functions.
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## Create Database and Table
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In this step we create the appropriate database and table schema in TDengine for receiving MQTT data. Open TDengine CLI and execute SQL bellow:
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```sql
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CREATE DATABASE test;
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USE test;
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CREATE TABLE sensor_data (ts TIMESTAMP, temperature FLOAT, humidity FLOAT, volume FLOAT, pm10 FLOAT, pm25 FLOAT, so2 FLOAT, no2 FLOAT, co FLOAT, sensor_id NCHAR(255), area TINYINT, coll_time TIMESTAMP);
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```
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## Configuring EMQX Rules
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Since the configuration interface of EMQX differs from version to version, here is v4.4.5 as an example. For other versions, please refer to the corresponding official documentation.
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### Login EMQX Dashboard
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Use your browser to open the URL `http://IP:18083` and log in to EMQX Dashboard. The initial installation username is `admin` and the password is: `public`.
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### Creating Rule
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Select "Rule" in the "Rule Engine" on the left and click the "Create" button: !
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### Edit SQL fields
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Copy SQL bellow and paste it to the SQL edit area:
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```sql
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SELECT
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payload
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FROM
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"sensor/data"
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```
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### Add "action handler"
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### Add "Resource"
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Select "Data to Web Service" and click the "New Resource" button.
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### Edit "Resource"
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Select "WebHook" and fill in the request URL as the address and port of the server running taosAdapter (default is 6041). Leave the other properties at their default values.
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### Edit "action"
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Edit the resource configuration to add the key/value pairing for Authorization. If you use the default TDengine username and password then the value of key Authorization is:
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```
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Basic cm9vdDp0YW9zZGF0YQ==
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```
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Please refer to the [ TDengine REST API documentation ](/reference/rest-api/) for the authorization in details.
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Enter the rule engine replacement template in the message body:
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```sql
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INSERT INTO test.sensor_data VALUES(
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now,
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${payload.temperature},
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${payload.humidity},
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${payload.volume},
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${payload.PM10},
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${payload.pm25},
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${payload.SO2},
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${payload.NO2},
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${payload.CO},
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'${payload.id}',
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${payload.area},
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${payload.ts}
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)
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```
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Finally, click the "Create" button at bottom left corner saving the rule.
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## Compose program to mock data
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```javascript
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{{#include docs/examples/other/mock.js}}
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```
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Note: `CLIENT_NUM` in the code can be set to a smaller value at the beginning of the test to avoid hardware performance be not capable to handle a more significant number of concurrent clients.
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## Execute tests to simulate sending MQTT data
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```
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npm install mqtt mockjs --save ---registry=https://registry.npm.taobao.org
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node mock.js
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```
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## Verify that EMQX is receiving data
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Refresh the EMQX Dashboard rules engine interface to see how many records were received correctly:
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## Verify that data writing to TDengine
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Use the TDengine CLI program to log in and query the appropriate databases and tables to verify that the data is being written to TDengine correctly:
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Please refer to the [TDengine official documentation](https://docs.tdengine.com/) for more details on how to use TDengine.
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EMQX Please refer to the [EMQX official documentation](https://www.emqx.io/docs/en/v4.4/rule/rule-engine.html) for details on how to use EMQX.
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