How to send clientid or topic in rules

EMQX
1

We’ve set up EMQX 5.0 in a kubernetes cluster running in GCP. We managed to create a data bridge with a rule that takes everything in a topic like /devices/# and we to create a rule to republish that into our webserver. The ${payload} works fine but we cannot work with the ${clientid} or ${topic}. What can be happening?

2

How is your SQL written? If you don’t use the form SELECT * FROM ..., then you need to select it manually, such as SELECT clientid, username FROM xxx

3

The strange thing is that I’ve tried with both * and the specific select like

SELECT clientid FROM “t/#”

When doing both, I managed to get the ${payload} nothing else works.

4

Hi, it is best to provide detailed configuration. Some variables only exist in specific events. For example, the payload variable only exists in the message.publish event.

5

Did you fix this?

I have the same issue:

Rule =
SELECT
*
FROM
“/config/#”

The payload is provided by the clientID is not.

Help!

6

If any one else runs into this. The issue is that Payload is a JSON object and the clientID is a string. You need to wrap the client string into a JSON object example:

{
    "deviceId" : "${clientid}",
    "payload" :  ${payload}
}