Convert PowerShell output to Python and store it in variable

Question

Sorry in advance for silly question.

I am trying to write simple python script that runs virtual machine using PowerShell commands.

I have got a little problem with converting output from PowerShell command to a variable in Python.

The idea is:

I launch virtual machine, after that I check the state of it and, if the state is Running - start all the activity.

It is not a problem to do it in PowerShell, I wrote all the commands (launch VM, check state, if statement etc), but it is a problem to do it from py file.

My script looks like that:

import subprocess
import time
import os


class Utils(object):
    def __init__(self):
        self.ps_exec = r"C:\path\PsExec.exe"
        self.power_shell = r"C:\path\powershell.exe"

    def vm(self, apply_vm_script):
        subprocess.Popen([self.power_shell, apply_vm_script])

util = Utils()

def turn_on_vm(vm_name, checkpoint_name):
    apply_vm_script = 'Invoke-Command -Computername name -ScriptBlock ' \
                           '{ Get-VM ''"' + vm_name + '"'' | get-vmsnapshot -Name ' + '"' + checkpoint_name + '" | ' \
                           'Restore-VMSnapshot -Confirm:$false ; Start-VM -Name ''"' + vm_name + '"''}'
    util.vm(apply_vm_script)
    time.sleep(10)
    
def check_if_vm_on(vm_name):
    check_vm_script = 'Invoke-Command -Computername name -ScriptBlock { Get-VM | where {$_.Name -eq ' + vm_name + ' } | where { $_.State -eq "Running" } | select Name,State}'
    util.vm(check_vm_script)
    time.sleep(3)
    
def test():    
    turn_on_vm('VM_name', 'checkpoint_name')
    if(check_if_vm_on('VM_name')):
        Do my activity
    
def main():
    test()
    
if __name__ == '__main__':
    main()

Also, I can perform all if actions in PowerShell, but also can't convert bool output into Python:

if($State -like '*Running*') { Write-Output "True" }

State was defined earlier, no problem with variables.

Any ideas how to solve it?

Thank you in advance!!!

Why... are you writing a Python script that runs PowerShell commands? Wouldn't it make sense to write a PowerShell script instead? — Tomalak
– Tomalak, Commented Jan 5, 2021 at 10:05
The main part of the script is Python commands. Only this in PowerShell. Its ok, just a bit easier for me. — user14943311
– user14943311, Commented Jan 5, 2021 at 10:07
You might be better off with writing a .ps1 script file that does all those things and takes a couple of arguments (vm name, checkpoint name), so you can a) test or use it independently of your Python script and b) have an easier time running it from Python. — Tomalak
– Tomalak, Commented Jan 5, 2021 at 10:28

assli100 · Accepted Answer · 2021-04-18 08:29:46Z

5

You need to get the stdout from the powershell script to your python program. This can be done with Popen.communicate().

def vm(self, apply_vm_script):
        p = subprocess.Popen([self.power_shell, apply_vm_script], stdout=subprocess.PIPE)
        result = p.communicate()[0]
        return str(result)

Also you need to return this value from check_if_vm_on

def check_if_vm_on(vm_name):
    check_vm_script = 'Invoke-Command -Computername name -ScriptBlock { Get-VM | where {$_.Name -eq ' + vm_name + ' } | where { $_.State -eq "Running" } | select Name,State}'
    result = util.vm(check_vm_script)
    time.sleep(3)
    return result

Then you will be able to check it with the if statement:

if(check_if_vm_on('VM_name') == "True"):
    Do my activity

edited Apr 18, 2021 at 8:29

answered Jan 5, 2021 at 10:29

assli100

5933 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user14943311 Over a year ago

Actually, I think I got it. p = subprocess etc..? Looks like it works, thank you very much. Sorry, but can't vote.

assli100 Over a year ago

Yes, sorry, p = subprocess. Fixed the answer

Collectives™ on Stack Overflow

Convert PowerShell output to Python and store it in variable

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related