10

Here is what I'd like to achieve in one way or another.

I have a custom assembly defining some objects. In my script, I create a custom object that I'd like to pass to a script block, keeping that object behavior.

Add-Type -AssemblyName MyCustomDLL

$global:object = new-object MyCustomDLL.MyCustomObject()
$object | gm

$jobWork = { param ($object) $object | gm } # I'd like to keep my object behavior in that block

$job = Start-Job -ScriptBlock $jobWork -ArgumentList $object
Wait-Job $job
Receive-Job $job

How can I do that or achieve the same effect? Thanks for your help

BartekB
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David Brabant
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2 Answers2

12

Instead of background jobs you may use PowerShell with BeginInvoke, EndInvoke. Here is the simple but working example of passing a live object in a "job", changing it there, getting the results:

# live object to be passed in a job and changed there
$liveObject = @{ data = 42}

# job script
$script = {
    param($p1)
    $p1.data # some output (42)
    $p1.data = 3.14 # change the live object data
}

# create and start the job
$p = [PowerShell]::Create()
$null = $p.AddScript($script).AddArgument($liveObject)
$job = $p.BeginInvoke()

# wait for it to complete
$done = $job.AsyncWaitHandle.WaitOne()

# get the output, this line prints 42
$p.EndInvoke($job)

# show the changed live object (data = 3.14)
$liveObject
Roman Kuzmin
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4

Background jobs are built on top of PowerShell remoting and as such, perform similar actions when passing objects around. They would serialize/ deserialize them rather than pass them with all their complexity.

My guess is that the only way to get complex object is just to pass constructor arguments and/ or operations as -ArgumentList and create object inside job.

In such a case also adding assembly would have to be part of the job:

Start-Job {
    param ($ConstructorArguments)
    Add-Type -AssemblyName MyCustomDll
    $object = New-Object MyCustomDll.MyCustomObject $ConstructorArguments
    $object | Get-Member
} -ArgumentList Foo, Bar | Wait-Job | Receive-Job
BartekB
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    If the object is statefull and you have already changed it's states in the calling script, that won't help. Is there another track than serialize/deserialize? – David Brabant Mar 13 '13 at 12:11