PowerShell: Start-Job, Get-Job, Receive-Job Examples

Demo 1: Obtain Public IP of a Windows Machine

# Commands to run locally
$command1={(Invoke-WebRequest -URI ("ifconfig.me/ip")).Content}
$command2={(Get-ADComputer $env:computername).DistinguishedName -Replace "^CN=[^,]+,",''}
$job1=start-job -ScriptBlock $command1
$job2=start-job -ScriptBlock $command2
$resultJob1 = (get-job (get-job -id $job1.Id).ChildJobs.Id).Output
$resultJob2 = receive-job -id $job2.Id

Demo 2: run jobs on 1 remote machine

# Invoke-Command to toward a remote Windows machine
$remoteComputer="COLO-Panda"
function getPublicIp{
    return (Invoke-WebRequest -URI ("ifconfig.me/ip")).Content;
    }
$job2=invoke-command -computername $remoteComputer -scriptblock {
                                                            param($getPublicIp)
                                                            [ScriptBlock]::Create($getPublicIp).Invoke()
                                                            } -args ${Function:getPublicIp} -asjob
$resultJob2 = receive-job -id $job2.Id

Demo 3: run jobs on multiple computers sequentially

$remoteComputers="SHERVER006","SHERVER007"
$results=@()

function getPublicIp{
    return (Invoke-WebRequest -URI ("ifconfig.me/ip")).Content;
    }

function executeFunctionRemotely{
    param(
        $remoteComputer        
        )
    #$credential=(get-credential)
    
    do{
        $session = New-PSSession -ComputerName $remoteComputer
        write-host "Connecting to remote computer $remoteComputer..."
        sleep -seconds 1
        if ($session){write-host "Connected."}
        } until ($session.state -match "Opened")

    $job=invoke-command -session $session -scriptblock{
                                                param($getPublicIp)
                                                [ScriptBlock]::Create($getPublicIp).Invoke()                                      
                                                } -args ${Function:getPublicIp} -asjob
    # Wait until job is completed
    do{
        $jobName=$job.Name
        $jobState = (Wait-Job -Name $jobName).State
        write-host "Checking status of  $jobName..."
        sleep -seconds 1
        if ($jobState -eq "Completed"){write-host "$jobName completed."}
    } until ($jobState -eq "Completed")    

    $result = receive-job $job.Id

    # Cleanup Routine
    Remove-Job -Name $job.Name -Force
    #$job|Remove-Job
    Remove-PSSession -id $session.Id

    return $result;
    }

foreach ($computer in $remoteComputers){
    $result=executeFunctionRemotely -remoteComputer $computer
    $results+=[PSCustomObject]@{ComputerName=$computer;PublicIp=$result};
    }

$results

<#
Connecting to remote computer SHERVER006...
Connected.
Checking status of  Job29...
Job29 completed.
Connecting to remote computer SHERVER007...
Connected.
Checking status of  Job31...
Job31 completed.
PS C:\Windows\system32>
PS C:\Windows\system32> $results

ComputerName   PublicIp
------------   --------
SHERVER006 9000.24.245.9000
SHERVER007 9000.24.245.9000
#>

Demo 3: run jobs on multiple computers simultaneously

$remoteComputers="SHERVER01","SHERVER02"
$results=@()
$jobs=@()

function pingDomain{
    ping -n 100 google.com;
    }

function startJobOnRemoteComputer{
    param(
        $remoteComputer,
        $functionToCall    
        )
    
    Write-Host "Executing $functionToCall on $remoteComputer";
    $script=(Get-Item "function:$functionToCall").Definition

    do{
        $session = New-PSSession -ComputerName $remoteComputer
        write-host "Connecting to remote computer $remoteComputer..."
        sleep -seconds 1
        if ($session){write-host "Connected."}
        } until ($session.state -match "Opened")

    $job=invoke-command -Session $session -AsJob -ScriptBlock{
                                                param($functionToCall);
                                                [ScriptBlock]::Create($functionToCall).Invoke();
                                                } -args $script  

    write-host "$($job.Name) has been initiated on $remoteComputer"  
    return $job;    
    }

foreach ($computer in $remoteComputers){
    $job=startJobOnRemoteComputer -remoteComputer $computer -functionToCall pingDomain
    $jobs+=[PSCustomObject]$job;
    }

$jobsCount=$jobs.count;
foreach ($job in $jobs){
    # Wait until job is completed
    do{
        $jobName=$job.Name
        $jobState = (Wait-Job -Name $jobName).State
        write-host "Checking status of  $jobName..."
        sleep -seconds 1
        if ($jobState -eq "Completed"){
            write-host "$jobName completed.";
            $result = receive-job $job.Id;
            $results+=[PSCustomObject]@{ComputerName="$($job.Location)";Result="$result"};
            Remove-Job -Name $job.Name -Force;
            }
    } until ($jobState -eq "Completed") 
}

# Cleanup sessions
get-job|remove-job
get-pssession|remove-pssession

$output=$results|ft -autosize|out-string
write-host $output

<# Sample Result
PS C:\Windows\system32> write-host $output
ComputerName   Result
------------   ------
SHERVER01       Pinging google.com [172.217.14.110] with 32 bytes of data:  Reply from 172.217.14.110: bytes=32 tim...
SHERVER02       Pinging google.com [172.217.14.110] with 32 bytes of data: Reply from 172.217.14.110: bytes=32 time=..
#>