multithread with runspaces instead of foreach cycle - powershell

Question

I have a script with a foreach cycle. It has about a dozen functions, each collecting information from remote machines' C$ share (cutting text files, checking file version, etc.)
This is however taking some time, since each machine's data collected after one by one. (sometimes it runs with 500+ input)
Wish to put this into runspaces with parallel execution, but so far no examples worked. I am quite new to the concept.
Current script's outline
$inputfile = c:\temp\computerlist.txt
function 1
function 2
function 3, etc
foreach cycle
function 1
function 2
function 3
All results written to screen with write-host for now.

Answer 1

This example pings a number of server in parallel, so you easily can modify it for your demands:
Add-Type -AssemblyName System.Collections
$GH = [hashtable]::Synchronized(#{})
[System.Collections.Generic.List[PSObject]]$GH.results = #()
[System.Collections.Generic.List[string]]$GH.servers = #('server1','server2','server3');
[System.Collections.Generic.List[string]]$GH.functions = #('Check-Server');
[System.Collections.Generic.List[PSObject]]$jobs = #()
#-----------------------------------------------------------------
function Check-Server {
#-----------------------------------------------------------------
# a function which runs parallel
param(
[string]$server
)
$result = Test-Connection $server -Count 1 -Quiet
$GH.results.Add( [PSObject]#{ 'Server' = $server; 'Result' = $result } )
}
#-----------------------------------------------------------------
function Create-InitialSessionState {
#-----------------------------------------------------------------
param(
[System.Collections.Generic.List[string]]$functionNameList
)
# Setting up an initial session state object
$initialSessionState = [System.Management.Automation.Runspaces.InitialSessionState]::CreateDefault()
foreach( $functionName in $functionNameList ) {
# Getting the function definition for the functions to add
$functionDefinition = Get-Content function:\$functionName
$functionEntry = New-Object System.Management.Automation.Runspaces.SessionStateFunctionEntry -ArgumentList $functionName, $functionDefinition
# And add it to the iss object
[void]$initialSessionState.Commands.Add($functionEntry)
}
return $initialSessionState
}
#-----------------------------------------------------------------
function Create-RunspacePool {
#-----------------------------------------------------------------
param(
[InitialSessionState]$initialSessionState
)
$runspacePool = [RunspaceFactory]::CreateRunspacePool(1, ([int]$env:NUMBER_OF_PROCESSORS + 1), $initialSessionState, $Host)
$runspacePool.ApartmentState = 'MTA'
$runspacePool.ThreadOptions = "ReuseThread"
[void]$runspacePool.Open()
return $runspacePool
}
#-----------------------------------------------------------------
function Release-Runspaces {
#-----------------------------------------------------------------
$runspaces = Get-Runspace | Where { $_.Id -gt 1 }
foreach( $runspace in $runspaces ) {
try{
[void]$runspace.Close()
[void]$runspace.Dispose()
}
catch {
}
}
}
$initialSessionState = Create-InitialSessionState -functionNameList $GH.functions
$runspacePool = Create-RunspacePool -initialSessionState $initialSessionState
foreach ($server in $GH.servers)
{
Write-Host $server
$job = [System.Management.Automation.PowerShell]::Create($initialSessionState)
$job.RunspacePool = $runspacePool
$scriptBlock = { param ( [hashtable]$GH, [string]$server ); Check-Server -server $server }
[void]$job.AddScript( $scriptBlock ).AddArgument( $GH ).AddArgument( $server )
$jobs += New-Object PSObject -Property #{
RunNum = $jobCounter++
JobObj = $job
Result = $job.BeginInvoke() }
do {
Sleep -Seconds 1
} while( $runspacePool.GetAvailableRunspaces() -lt 1 )
}
Do {
Sleep -Seconds 1
} While( $jobs.Result.IsCompleted -contains $false)
$GH.results
Release-Runspaces | Out-Null
[void]$runspacePool.Close()
[void]$runspacePool.Dispose()

Answer 2

This would be concurrent and run in about 10 seconds total. The computer could be localhost three times if you got it working.
invoke-command comp1,comp2,comp3 { sleep 10; 'done' }
Simple attempt at api (threads):
$a = [PowerShell]::Create().AddScript{sleep 5;'a done'}
$b = [PowerShell]::Create().AddScript{sleep 5;'b done'}
$c = [PowerShell]::Create().AddScript{sleep 5;'c done'}
$r1 = $a.BeginInvoke(); $r2 = $b.BeginInvoke() $r3 = $c.BeginInvoke()
$a.EndInvoke($r1); $b.EndInvoke($r2); $c.EndInvoke($r3)
a done
b done
c done