github runner on Windows not finding executables on PowerShell

Question

I am trying to use a self-hosted Windows-VM to run west for repo management, python to run some scripts, and git to push back to the repo.

The work is to generate files using python from repo-A as artifacts to check-into repo-B. I had to use Windows because the file generation tools only works on Windows.

I have a self-hosted build agent setup and able to run github actions on it.

On the VM side, these are the path to the relevant commands (showing that they are properly added to $PATH)

PS C:\TouchGFXProjects\wallSwitch-gui-hesPrototype-480-272> gcm west; gcm tgfx.exe; gcm python; gcm git

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Application     west.exe                                           0.0.0.0    C:\Users\tgfx\AppData\Local\Programs\Python\Python39\Scripts\west.exe
Application     tgfx.exe                                           4.16.1.0   C:\TouchGFX\4.16.1\designer\tgfx.exe
Application     python.exe                                         3.9.515... C:\Users\tgfx\AppData\Local\Programs\Python\Python39\python.exe
Application     git.exe                                            2.31.1.1   C:\Program Files\Git\cmd\git.exe

The VM's execution Policy is set to:

PS C:\Windows\system32> Get-ExecutionPolicy -List
        Scope ExecutionPolicy
        ----- ---------------
MachinePolicy       Undefined
   UserPolicy       Undefined
      Process       Undefined
  CurrentUser       Undefined
 LocalMachine          Bypass

All the scrips and execution steps ran well when executed from powerShell on the VM itself. But when I invoke the github runner, the behaviour indicates that it does not know where the executables are, despite it being known in $PATH (see debug output below).

github runner script:

name: CI

on:
    workflow_dispatch:
    pull_request:
        branches:
            - master
            - 'feature/**'

jobs:
  # Test-path access using powerShell shell
  test-path-powerShell:
    runs-on: [self-hosted, Windows, X64, touchGFX]
    steps:
      - name: Display the path
        run: echo ${env:PATH}
        shell: powershell
        continue-on-error: true

      - name: Check that we know where python is
        run: gcm python
        shell: powershell
        continue-on-error: true

      - name: Test calling "python.exe --version" via powershell
        run: python.exe --version
        shell: powershell
        continue-on-error: true
  
      - name: Test calling "python.exe --version" via powershell (abs path)
        run: C:\Users\tgfx\AppData\Local\Programs\Python\Python39\python.exe --version
        shell: powershell
        continue-on-error: true

When running on the github runner, the echo ${env:PATH} command shows:

Run echo ${env:PATH}
C:\TouchGFX\4.16.1\designer;C:\Users\tgfx\AppData\Local\Programs\Python\Python39\;C:\Users\tgfx\AppData\Local\Programs\Python\Python39\Scripts\;C:\Users\tgfx\AppData\Local\Programs\Python\Python39\Lib\site-packages;C:\Program Files\Git\cmd;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Windows\ServiceProfiles\NetworkService\AppData\Local\Microsoft\WindowsApps

Which means it should have the location for python.exe

However, all commands that attempts to access it (even with Absolute path) returns errors like this:

Run gcm python
gcm : The term 'python' is not recognized as the name of a cmdlet, function, script file, or operable program. Check 
the spelling of the name, or if a path was included, verify that the path is correct and try again.
At C:\actions-runner\_work\_temp\c19697cd-d5e0-4102-a7b6-5f357f82aa91.ps1:2 char:1
+ gcm python
+ ~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (python:String) [Get-Command], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException,Microsoft.PowerShell.Commands.GetCommandCommand

I also tried appending python to $GITHUB_PATH with:

echo "C:\Users\tgfx\AppData\Local\Programs\Python\Python39" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append

But that just extends the output of echo ${env:PATH} and still leads to the same error on execution.

What am I missing?

Thanks for everyone's time.

Answer 1

In my setup, the missing piece is the access permissions of the Github Action Runner Service. The default of NT AUTHORITY\NETWORK SERVICE used when installing the runner as a service does not work. I tested changing the service's permission to both Local Service and Local System and found that Local System works.

You need to restart the service when changing the permissions for it to take effect.

Within the github runner workflow, you can validate the settings using the whoami command from powershell.