(Solved via API instead) ShellSensor to obtain temperature sensor value via ssh not working

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Hello.

My pimatic server is running on a Rasperry Pi and, from there, I have a valid working SSH root connection to another Raspberry Pi (sitting in 172.16.23.11).

I have created a ShellSensor device to try to obtain a temperature sensor value via ssh, and I can’t get it work properly.
I always get Host key verification failed error.

I have created my ShellSensor like this:

{
      "attributeName": "temperature",
      "attributeType": "number",
      "attributeUnit": "ºC",
      "command": "ssh root@172.16.23.11 'bash /storage/read_sensor.sh'",
      "interval": 60000,
      "id": "temperatura-sala",
      "name": "Temperatura Sala",
      "class": "ShellSensor",
      "hap": {
        "service": "Lightbulb"
      }
    }

I always get error message when saving the device:

error [pimatic-shell-execute]: [ShellSensor#temperatura-sala] Error: Command failed: /bin/sh -c ssh root@172.16.23.11 'bash /storage/read_sensor.sh'
Host key verification failed.

If I run this same command via SSH in my Pimatic Raspberry Pi server:

pi@homekit:~ $ /bin/sh -c "ssh root@172.16.23.11 'bash /storage/read_sensor.sh'"
18.25

Does anyone know why this happens and can help figure this out?

I’m also open to new/different ways of achieving this…

Thanks in advance.

The “problem” is that pimatic is running as root. The user root don’t have access to the ssh keys of the user pi.
Try to change the command to
sudo -H -u pi -c "ssh root@172.16.23.11 'bash /storage/read_sensor.sh'"
I don’t have test this command, but should be running.

Isn’t it much easier to run a script on the other side/pi to push the temperature over API to pimatic ?

I start motion service with

sshpass -p ‘secpipassword’ ssh -o StrictHostKeyChecking=no pi@192.168.0.100 ‘sudo service motion start’

Maybe StrictHostKeyChecking=no helps

@koffienl
It might be, that’s why I was looking for other options.

Would you be able to point to API documentation so I can try it?

Thanks in advance.

does this help? http://www.linuxproblem.org/art_9.html
well, it’s an instruction on establishing a ssh connection, but as i see you already have done that.

@leader21
Not really, but thanks anyway.

Can anyone point at solid API documentation I can start looking into?

@pplucky said in ShellSensor to obtain temperature sensor value via ssh not working:

@koffienl
It might be, that’s why I was looking for other options.

Would you be able to point to API documentation so I can try it?

Thanks in advance.

curl --silent -X PATCH --header "Content-Type:application/json" --user "admin:admin" --data '{"type": "value", "valueOrExpression": 666}' http://pimatic_ip/api/variables/VarName

@koffienl said in ShellSensor to obtain temperature sensor value via ssh not working:

curl --silent -X PATCH --header "Content-Type:application/json" --user "admin:admin" --data '{"type": "value", "valueOrExpression": 666}' http://pimatic_ip/api/variables/VarName

This led me in the right path of changing my device type from ShellSensor to VariablesDevice, define variables for each value I wanted to receive from the sensor resident in a different RPi and then update these variables via API directly from the RPi.

Thanks a lot everyone for all your help.