I have a simple workflow with a parallel loop but i run into an error when writing out the result. Because the write-output is parallel. I get the error:
The process cannot access the file because it is being used by another process.
Here is my script:
workflow Get-ServerServices
{
$srvlst = Get-Content C:\TEMP\srvlst.txt
foreach -parallel ($srv in $srvlst)
{
Get-Service -PSComputerName $srv | Out-File c:\temp\test.txt -Append
}
}
any idea?
I would suggest writing out to temporary files. You could do something like the below code:
workflow Get-ServerServices
{
#Get the temp path of the context user
$TempPath = Join-Path -Path $([System.IO.Path]::GetTempPath()) -ChildPath "ServerServices"
New-Item -Path $TempPath -ItemType Directory # and create a new sub directory
$srvlst = Get-Content C:\TEMP\srvlst.txt
foreach -parallel ($srv in $srvlst)
{
$TempFileName = [System.Guid]::NewGuid().Guid + ".txt" #GUID.txt will ensure randomness
$FullTempFilePath = Join-Path -Path $TempPath -ChildPath $TempFileName
Get-Service -PSComputerName $srv | Out-File -Path $FullTempFilePath -Force #Write out to the random file
}
$TempFiles = Get-ChildItem -Path $TempPath
foreach ($TempFile in $TempFiles) {
Get-Content -Path $TempFile.FullName | Out-File C:\temp.txt -Append #concatenate all the files
}
Remove-Item -Path $TempPath -Force -Recurse #clean up
}
Basically you are getting the temp dir, appending a new directory, adding a bunch of GUID named text files with your output, concatenating them all into one, and then removing all of them
You can do it in a simpler form by using a buffer and outputting buffer contents at the end:
workflow Get-ServerServices
{
$srvlst = Get-Content C:\TEMP\srvlst.txt
$out = @()
foreach -parallel ($srv in $srvlst)
{
$WORKFLOW:out += (Get-Service -ComputerName $srv)
}
Out-File c:\temp\test.txt -InputObject $out
}
see technet "Variables in Parallel and Sequence Statements" for more info
Create the test.txt file name based on a variable - then you will have no conflicts.
At the end of the process gather up all the individual files and create one file with all the results - then remove the individual files as part of the cleanup'
As of Powershell 6, Workflow with Foreach-object is no longer used, also the parameter pass has been changed, follow an example below, see if it helps.
# Default directory variable
$DefaultDir = "C:\temp\sample"
# Log file.
$LogFile = "$($DefaultDir)\Log\Log_$([DateTime]::Now.ToString("yyyyMMdd-HHmmss")).txt"
# Directory where all computers are listed.
$AllComputerFolder = "$($DefaultDir)\ListToCheck\pcs.txt"
# Scan the file that lists all machines to be scanned.
Get-Content $AllComputerFolder | ForEach-Object -Parallel {
# It will only scan for machines that are connected to the network.
$TurnedOn = Test-Connection -BufferSize 8 -Count 1 -ComputerName $($_ -replace "\\", "") -Quiet
# Will scan only for machines that are connected
IF($TurnedOn -eq $True){
# Run your script, notice the new way of passing parameters within Foreach-object: $using:DefaultDir
$Return = ."$using:DefaultDir\Script\script.ps1" $_
# Writes in file the return of the processing of each machine.
Add-Content -Path "$using:LogFile" -Value $Return
}ELSE{
# Writes the return of machines with error to file
Add-Content -Path "$using:LogFile" -Value "$($_) : $([DateTime]::Now.ToString("yyyyMMdd-HHmmss")) : Machine turned-off or out of the network"
}
# Number of simultaneous threads
} -ThrottleLimit 20
