Integrate with TimescaleDB

In this article, we will simulate temperature and humidity data and report these data to EMQX Cloud via the MQTT protocol and then use the EMQX Cloud Data Integrations to dump the data into TimescaleDB.

Before you start, you will need to complete the following:

• A deployment (EMQX Cluster) has been created on EMQX Cloud.
• For Professional Plan users: Please complete Peering Connection Creation first, all IPs mentioned below refer to the internal network IP of the resource.(Professional Plan with a NAT gateway can also use public IP to connect to resources).
• For BYOC Plan users: Please establish a peering connection between the VPC where BYOC is deployed and the VPC where the resources are located. All IPs mentioned below refer to the internal IP of the resources. If you need to access the resources via public IP addresses, please configure a NAT gateway in your public cloud console for the VPC where BYOC is deployed.

TimescaleDB Configuration

1. Install TimescaleDB

   docker run -d --name timescaledb -p 5432:5432 -e POSTGRES_PASSWORD=password timescale/timescaledb:1.7.4-pg12

2. Create database

   docker exec -it timescaledb psql -U postgres
   CREATE database emqx;
   \c emqx

3. Create table

   Use the following SQL statement to create temp_hum table. This table will be used to save the temperature and humidity data reported by devices.

   CREATE TABLE temp_hum (
       up_timestamp   TIMESTAMPTZ       NOT NULL,
       client_id      TEXT              NOT NULL,
       temp           DOUBLE PRECISION  NULL,
       hum            DOUBLE PRECISION  NULL
   );
   
   SELECT create_hypertable('temp_hum', 'up_timestamp');

4. Insert test data and view it

   INSERT INTO temp_hum(up_timestamp, client_id, temp, hum) VALUES (to_timestamp(1603963414), 'temp_hum-001', 19.1, 55);
   
   SELECT * FROM temp_hum;

Data Integrations Configuration

Go to Deployment Details and click on Data Integrations on the left menu bar.

1. Create TimescaleDB Resource

   Click on TimescaleDB under the Data Persistence.

   

   Fill in the timescaledb database information you have just created and click Test. If there is an error, you should check if the database configuration is correct. Then click on New to create TimescaleDB resource.

   

2. Create Rule

   Choose the TimescaleDB resource under Configured Resources, click on New Rule and enter the following rule to match the SQL statement. In the following rule we read the time up_timestamp when the message is reported, the client ID, the message body (Payload) from the temp_hum/emqx topic and the temperature and humidity from the message body respectively.

   SELECT 
   timestamp div 1000 AS up_timestamp, clientid AS client_id, payload.temp AS temp, payload.hum AS hum
   FROM
   "temp_hum/emqx"

   

3. Create Action

   Click on the Next button in the bottom to enter action view. Select the resource created in the first step and enter the following data to insert into the SQL template.

   INSERT INTO temp_hum(up_timestamp, client_id, temp, hum) VALUES (to_timestamp(${up_timestamp}), ${client_id}, ${temp}, ${hum})

   Click on Confirm to create action.

4. View Resource Detail

   Click on the resource to see the detail.

   

5. Check Rule Monitoring

   Click the monitor icon of rule to see the metrics

   

Test

1. Use MQTTX to simulate temperature and humidity data reporting

   You need to replace broker.emqx.io with the created deployment connection address, and add client authentication information to the EMQX Dashboard.

2. View data dump results

   select * from temp_hum order by up_timestamp desc limit 10;