Functions/Find-Python.ps1

# ===========================================================================
# Find-Python.ps1 ---------------------------------------------------------
# ===========================================================================

# function ----------------------------------------------------------------
# ---------------------------------------------------------------------------
function Find-Python {

    <#
    .SYNOPSIS
        Find a path, where a python distribution might located.
 
    .DESCRIPTION
        Find a path, where a python distribution might located. 'Find-Python' searches for a python distribution in configuration file and environment variable '%PYTHONHOME%'. Via flag 'Force' the python package 'virtualenv' can be installed in valide distribution.
 
    .PARAMETER Python
 
    .PARAMETER FORCE
 
    .EXAMPLE
        PS C:\> Find-Python
 
        C:\Python\Python37\python.exe
 
        -----------
        Description
        Return the path to an existing executable of a python distribution
 
    .EXAMPLE
        PS C:\> Find-Python -PathC:\Python\Python37
 
        C:\Python\Python3\python.exe
 
        -----------
        Description
        Return the path to an existing executable of a python distribution
 
    .EXAMPLE
        PS C:\> Find-Python -Path C:\Python\Python37\python.exe
 
        C:\Python\Python3\python.exe
 
        -----------
        Description
        Return the path to an existing executable of a python distribution
 
    .EXAMPLE
        PS C:\> Find-Python -Path C:\Python\Python37\python.exe
 
        C:\Python\Python3\python.exe
 
        -----------
        Description
        Return the path to an existing executable of a python distribution
 
    .INPUTS
        System.String. Path to a folder or executable of a python distribution.
     
    .OUTPUTS
        System.String. Path to an existing executable of a python distribution
    #>


    [CmdletBinding(PositionalBinding=$True)]

    [OutputType([System.String])]

    Param(        
        [Parameter(Position=1, ValueFromPipeline=$True, HelpMessage="Path to a folder or executable of a python distribution.")]
        [System.String] $Path,

        [Parameter(HelpMessage="Forces installation of package 'virtualenv' if not found.")]
        [Switch] $Force
    )

    Process{

        # if the specified path does not contain an executable, try to detect the standard python distribution in system path
        $python_list = @(
            "$Path",
            "$($PSVirtualEnv.Python)",
            [System.Environment]::GetEnvironmentVariable($PSVirtualEnv.EnvPython, "user"),
           [System.Environment]::GetEnvironmentVariable($PSVirtualEnv.EnvPython, "machine")
        )

        for($i= 0; $i -lt $python_list.Length; $i++){

            if ($python_list[$i] -and -not $python_list[$i].EndsWith('python.exe')){
                $python_list[$i] = Join-Path -Path $python_list[$i] -ChildPath "python.exe"
            } 

            # check, whether the defined executbale does exist
            if (Test-Path $python_list[$i]) 
            {   
                $python_packages = Get-VirtualEnvPackage -Python $python_list[$i] -Unformatted
                if (-not ($python_packages | Where-Object {$_.Name -eq "virtualenv"})) {
                    if (-not $Force) {
                        Write-FormattedError -Message "The python distribution does not provide the required package 'virtualenvwrapper'. Please install the package manually." -Module $PSVirtualEnv.Name -Space -Silent:(!$VerbosePreference)
                            return
                    }
                    else {
                        . $python_list[$i] -m pip install virtualenv 2>&1> $Null
                        Write-FormattedWarning -Message "The python distribution does not provide the required package 'virtualenvwrapper'. Package will be installed automatically for full functionality." -Module $PSVirtualEnv.Name -Space -Silent:(!$VerbosePreference)
                    }
                }

                return  $python_list[$i]
            }
        }

        Write-FormattedError -Message "The python distribution can not be located. Set an existing python distribution in configuration file or set the environment variable '$($PSVirtualEnv.EnvPython)'" -Module $PSVirtualEnv.Name -Space -Silent:(!$VerbosePreference)
        return
    }
}