Add ImportPSModulesFromPath support

[beargle]

Do you want to request a feature or report a bug?
Feature

What is the current behavior?
Importing modules in background runspace jobs requires that the module be:

• "Installed" and accessible in $env:PSModulePath
• Passed by name to Start-RSJob using the -ModuleToImport parameter

What is the proposed behavior?
Add support for passing a custom module path, from which modules will be imported into background runspace jobs.

This should require no modification of $env:PSModulePath, and shouldn't require the module to be pre-installed on the client. Expecting something similar to how modules are specified for import in psake-config.ps1. Specific use case is a portable CI/CD pipeline that manages PowerShell module dependencies, without relying on Install-Module or a specific build server configuration.

It looks like InitialSessionState.ImportPSModulesFromPath() could work for this, but would make a hard dependency on PowerShell V3. Wasn't sure if PowerShell V2 support was still important based on #162.

Please provide a code example showing the potential feature, if applicable:
Today we pass in one or more module names to import, which have to be accessible with $env:PSModulePath

Start-RSJob -ModulesToImport @("Pester")...

Would like to be able to pass in a custom module path, from which one or more modules are imported. Assuming a directory structure of:

Dependencies/
    PowerShell/
        Modules/

We should be able to:

Start-RSJob -ModulesFromPathToImport ".\Dependencies\PowerShell\Modules"...

[beargle]

If this looks like something that would be useful, I'm happy to put together a PR for review. Thanks!

[proxb]

@beargle This sounds cool! I am definitely done with adding new features for V2 and have already moved the V2 supporting module onto its own branch. I just need to work on removing the V2 code as well as adding a warning when this module is imported from a V2 host. I should have that completed by the end of the week if you can wait until then, otherwise go ahead and do the PR and I will merge it and then begin work on removing the V2 stuff.

[MVKozlov]

btw this can be done thru -ModulesToImport parameter like Import-Module -Name.
If supplied path exists, that it is path to module, if not - just module name
and path can support wildcards thru Resolve-Path

[beargle]

@MVKozlov Good point about similar functionality with -ModulesToImport; I do see that it could be used if the collection of module paths is pre-built with Resolve-Path and wildcards.

I haven't been able to get -ModulesToImport to work with a single path that contains module subdirectories (ex. like what Windows users have at ~\Documents\WindowsPowerShell\Modules). Am I missing something on that front?

Regardless, PR has been raised - would appreciate any feedback you all have. Thanks!

[MVKozlov]

I this this way close to your needs

$list = 'PoshWSUS', 'D:\Work\ps\test\', 'D:\Work\ps\test\PSAlphaFS\2.0.0.1\*.psm1'

$modulenames = New-Object System.Collections.ArrayList
$modulepaths = $list | ForEach-Object {
  $m = $_
  try {
    Resolve-Path $_ -ErrorAction Stop | Select-Object -ExpandProperty Path
  }
  catch {
    $null = $modulenames.Add($m)
  }
}
$modulenames
$modulepaths

here I'm split common list to names and paths