OpenHAB calling external scripts from openHAB

Setup, Configuration and Use Scripts & Rules
1

Hi all,

I was just wondering if anyone has any experience with calling external scripts from openHAB’s rules and scripting language. For example possibly having a rule which uses the openHAB timers to call a python script every X seconds. If not is there anyway to execute shell commands from openHAB’s scripting language. I am currently running openHAB on the raspberry pi with the latest version of openhabian.

Edit:
I have found this executeCommandLine(String commandLine), haven’t had a chance to test it yet but could be of help to people https://www.openhab.org/docs/configuration/actions.html#exec-actions

2

What version? I know there was whitelisting implemented in 2.5.2 for exec. I do not know if that affects other external script calls.

3

This was the image I downloaded and flashed to my SD card running on the raspberry pi 3 https://github.com/openhab/openhabian/releases/tag/v1.5

4

executeCommandLine is not affected by the whitelist issue… no worries

yes, sounds like a great use for a rule triggered by cron, see here

getting an external script running from a rule can be a little tricky
first make sure it runs as the openhab user from the command line
make sure openhab user owns script and script is executable ect

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5

If you just freshly installed, you are running openHAB 2.5.2. the openHABian image itself does not contain openHAB but downloads the current stable version.

6

You may want to look at Jython scripting to keep things in the same language. Jython is basically Python 2.

7

I have seen things about Jython on the openHAB website but haven’t looked too much into it. The scripts I am currently running now are in python 3 but I would like to try to integrate them into openHAB so it can handle more of the scheduling of scripts so I don’t have to implement it myself in the python scripts.

8

@rlkoshak and @5iver are a couple of the experts here.

9

Here’s a bundle to make the install go smoother…

And here is the documentation for the helper libraries…

https://openhab-scripters.github.io/openhab-helper-libraries/index.html

Other than needing an import, the executeCommandLine Action is used just as it is in the DSL…

https://openhab-scripters.github.io/openhab-helper-libraries/Guides/Actions.html?highlight=executecommandline

2 Likes
10

Thanks for the resources Scott. I have been messing around with the executeCommandLine Action and have got it running external scripts that I have in python3. The code looks something like this in case anyone else was interested and is located in the rules/ directory of openHAB. The permissions on the python files also had to be changed to give openHAB access to them.

rule Test_Volts
when
  System started
then 
   var result1 = executeCommandLine("python3 /home/openhabian/Environments/env_1/openHAB_Proj/bin/main.py")
logInfo("Test_Volts", result1)
end
1 Like
11

Assuming it is not massive, if you post your script I’ll convert it over to scripted automation.

2 Likes
12

I am going to see how this works out with just calling them as I have my own python packages that I created so might be a bit of work in it, thanks for the offer though. If i do end up having to convert them I’ll probably ask you for few pointers if thats ok? :grinning:

1 Like
13

HABApp runs on python3 natively and can call functions from your script without any changes.
Or you can use the built in scheduler:

import HABApp

class MyRule(HABApp.Rule):

    def __init__(self):
        super().__init__()
        self.run_minutely(self.run_every_min)

    def run_every_min(self):
        self.execute_subprocess(self.proc_finished, 'path_to_executable', 'arg1', capture_output=True)
        
    def proc_finished(self, info: HABApp.rule.FinishedProcessInfo):
        print(info.returncode)
        print(info.stdout)
1 Like