How to import modules in background in powershell?

Question

I have a few modules in my powershell profile, and their loading sometimes takes a lot of time (10-15s). I would like to load them in a background thread using something like this:

Start-Job -ScriptBlock { Import-Module -Global DockerCompletion }

The problem is that even though the documentation states that Import-Module uses global scope as a default, when I use Get-Module in the parent shell the module is not listed, so it was not loaded even though the job states completed.

Some of modules I use:

Import-Module “$env:ChocolateyInstall\helpers\chocolateyProfile.psm1” -Force
Import-Module WSLTabCompletion
Import-Module posh-git
Import-Module npm-completion
Import-Module DockerCompletion

EDIT: I am using pwsh 7.1

Rafaelita

Apart from the first one, which looks like it installs somewhere custom, don't the others just auto-load when needed? As long as the modules are in a known location (somewhere in the $PsModulePath, which could include your custom path), PowerShell should do this as required: Implicitly Importing a Module – Apprehend

@Apprehend Does not work like that. If the completion module is not loaded it will not trigger. I double checked that right now. – Rafaelita

Start-Job runs the background job in a separate process, so doesn't affect the global scope of the calling session. – Toluate

There might be a solution here using ThreadJobs but this requires PowerShell Core. Alternatively you might be able to whip something up using [System.Threading.Thread]::Start, but I don't have any ready examples or code to provide as an answer here. – Exocarp

Also, what do you mean "if the completion module is not loaded it will not trigger"? I've written a couple of modules and if they are on the module path they automatically load. I've not done anything specific to get command completion working, and they fit the rules of autoloading modules in PowerShell. – Exocarp

It looks like the completion modules are using Register-ArgumentCompleter to generate and add various tab-completion behaviors rather than functions/cmdlets. I think you cannot do this in the background either since they need to register in the current context. – Inkberry

I also did some testing with both the PSThreadJob (open source module for 5.1 thread jobs) and the official ThreadJob module for PS Core, neither seem to be able to import a module where it is usable from the invoking session, at least not by default. – Exocarp

@BendertheGreatest So essentially the module is badly written and I cannot load it in the background? I am using pwsh 7.1 BTW if that makes any difference. – Rafaelita

I'm saying I did some testing with threadjob solutions available to both PowerShell Core and Windows PowerShell, and neither showed modules imported in the thread job were available from the main thread (used Get-Module to see which modules were loaded in the current session). To be fair, I have not gone the full mile of inspection to see what members are available from the threadjob objects, but at a glance it doesn't seem like a background thread will work for importing modules. – Exocarp

In theory objects changed in the background thread should eventually make their way to the main thread, but the ways to force this behavior I'm not sure whether this can be done with ThreadJobs or not. There might be some way to make this work if you use the System.Threading namespace directly. – Exocarp

You don't need to import any modules if they are already installed in your modules folder as listed in $env:PSModulePath – Shophar

@Shophar The folders are in the modules path, yet they do not start working until the Import*modules command is complete – Rafaelita

Then you need to contact the author. That is not how PowerShell modules are supposed to work in PowerShell 3.0 and later. – Shophar

github.com/dahlbyk/… I think tab completion does need import-module in profile. – Clarance

As long as the modules is stored properly in the module path they will autoload. Check that they are stored in a folder listed in $env:PSModulePath -split ';' – Shophar