How to Start-Job ForEach IP and associate IP with a name for file

Question

I have a script from here, this is the job :

function CaptureWeight {
    Start-Job -Name WeightLog -ScriptBlock {
        filter timestamp {
            $sw.WriteLine("$(Get-Date -Format MM/dd/yyyy_HH:mm:ss) $_")
        }

        try {
            $sw = [System.IO.StreamWriter]::new("$using:LogDir\$FileName$(Get-Date -f MM-dd-yyyy).txt")
            & "$using:PlinkDir\plink.exe" -telnet $using:SerialIP -P $using:SerialPort | TimeStamp
        }
        finally {
            $sw.ForEach('Flush')
            $sw.ForEach('Dispose')
        }
    }
}

I'd like to get his to run against a list of IP addresses while also having a name associated with the IP to set the file name for each file. I was thinking something like $Name = Myfilename and $name.IP = 1.1.1.1 and using those in place of $FileName and $SerialIP, but have yet to be able get anything close to working or find an example close enough to what I'm trying for.

Thanks

Answer 1

Here is one way you could do it with a hash table as Theo mentioned in his helpful comment. Be aware that Jobs don't have a Threshold / ThrottleLimit parameter as opposed to Start-ThreadJob or ForEach-Object -Parallel since jobs run in a different process as you have already commented instead of instances / runspaces, there is no built-in way to control how many Jobs can run at the same time. If you wish have control over this you would need to code it yourself.

# define IPs as Key and FileName as Value
$lookup = @{
    '1.2.3.4'      = 'FileNameForThisIP'
    '192.168.1.15' = 'AnotherFileNameForTHatIP'
}

# path to directory executable
$plink = 'path\to\plinkdirectory'
# path to log directory
$LogDir = 'path\to\logDirectory'
# serial port
$serialport = 123

$jobs = foreach($i in $lookup.GetEnumerator()) {
    Start-Job -Name WeightLog -ScriptBlock {
        filter timestamp {
            $sw.WriteLine("$(Get-Date -Format MM/dd/yyyy_HH:mm:ss) $_")
        }
        
        try {
            $path = Join-Path $using:LogDir -ChildPath ('{0}{1}.txt' -f $using:i.Value, (Get-Date -f MM-dd-yyyy))
            $sw = [System.IO.StreamWriter]::new($path)
            $sw.AutoFlush = $true
            & "$using:plink\plink.exe" -telnet $using:i.Key -P $using:serialPort | TimeStamp
        }
        finally {
            $sw.ForEach('Dispose')
        }
    }
}

$jobs | Receive-Job -AutoRemoveJob -Wait

The other alternative to the hash table could be to use a Csv (either from a file with Import-Csv or hardcoded with ConvertFrom-Csv).

Answer 2

Adding here another alternative to my previous answer, using a RunspacePool instance which has built-in a way of concurrency and enqueuing.

using namespace System.Management.Automation.Runspaces

try {
    # define number of threads that can run at the same time
    $threads = 10

    # define IPs as Key and FileName as Value
    $lookup = @{
        '1.2.3.4'      = 'FileNameForThisIP'
        '192.168.1.15' = 'AnotherFileNameForTHatIP'
    }

    # path to directory executable
    $plink  = 'path\to\plinkdirectory\'
    # path to log directory
    $LogDir = 'path\to\logDirectory'
    # serial port
    $port   = 123

    $iss    = [initialsessionstate]::CreateDefault2()
    $rspool = [runspacefactory]::CreateRunspacePool(1, $threads, $iss, $Host)
    $rspool.ApartmentState = 'STA'
    $rspool.ThreadOptions  = 'ReuseThread'

    # session variables that will be intialized with the runspaces
    $rspool.InitialSessionState.Variables.Add([SessionStateVariableEntry[]]@(
        [SessionStateVariableEntry]::new('plink', $plink, '')
        [SessionStateVariableEntry]::new('serialport', $port, '')
        [SessionStateVariableEntry]::new('logDir', $LogDir, '')
    ))
    $rspool.Open()

    $rs = foreach($i in $lookup.GetEnumerator()) {
        $ps = [powershell]::Create().AddScript({
            param($pair)

            filter timestamp {
                $sw.WriteLine("$(Get-Date -Format MM/dd/yyyy_HH:mm:ss) $_")
            }

            try {
                $path = Join-Path $LogDir -ChildPath ('{0}{1}.txt' -f $pair.Value, (Get-Date -f MM-dd-yyyy))
                $sw = [System.IO.StreamWriter]::new($path)
                $sw.AutoFlush = $true

                & "$plink\plink.exe" -telnet $pair.Key -P $serialPort | TimeStamp
            }
            finally {
                $sw.ForEach('Dispose')
            }
        }).AddParameter('pair', $i)

        $ps.RunspacePool = $rspool

        @{
            Instance    = $ps
            AsyncResult = $ps.BeginInvoke()
        }
    }

    foreach($r in $rs) {
        try {
            $r.Instance.EndInvoke($r.AsyncResult)
            $r.Instance.Dispose()
        }
        catch {
            Write-Error $_
        }
    }
}
finally {
    $rspool.ForEach('Dispose')
}