after running successfully a few times it now returns

u need to cleanup when the invoked process ends

process.on('exit', function() {
  if (x) {
    x.kill();
  }
});

this.path

so, you can add that to the config info you send down in the typical

sendSocketNotification(“somevalue”, this.config)

to pass parameters to the node_helper

node testit.js

Yes, that works in the console.

testit.py

import sys 
# Takes first name and last name via command  
# line arguments and then display them 
print("Output from Python") 
print("First name: " ) 
print("Last name: " ) 

testit.js

  var spawn = require("child_process").spawn; 

    // Parameters passed in spawn - 
    // 1. type_of_script 
    // 2. list containing Path of the script 
    //    and arguments for the script  

    // E.g : http://localhost:3000/name?firstname=Mike&lastname=Will 
    // so, first name = Mike and last name = Will 
    var process = spawn('python3',["./testit.py"]); 
   //                         req.query.firstname, 
     //                       req.query.lastname] ); 
  
    // Takes stdout data from script which executed 
    // with arguments and send this data to res object 
    process.stdout.on('data', (data)=> { 
        console.log("received " +data); 
    } ) 

works for me… (note python script path is ./, make sure u have right path to py file)

then do
node testit.js

you are seeing the “I’m trying to retrieve data”

in the terminal window where you did npm start, right?

const spawn = require("child_process").spawn
var NodeHelper = require("node_helper")


module.exports = NodeHelper.create({
  start: function() {
    this.countDown = 10000000
  },
  socketNotificationReceived: function(notification, payload) {
      switch(notification){
          case "DO_YOUR_JOB":
            console.log(payload)
            this.sendSocketNotification("I_DID", (this.countDown - payload))
            break
          case "RETRIEVE_DATA":
            console.log(payload)
            this.job()
            break
      }
  },
  job: function(){
    console.log("I'm trying to retrieve data")
   var process = spawn("python3", ["return_something.py"])
    process.stdout.on('data', (data)=>{
      //********everything works up till here
        console.log("inside")
      var result = String.fromCharCode.apply(null, new Uint16Array((data)))
      this.sendSocketNotification("DATA_RETRIEVED", result)
    })
  }
})