handle error output, to signal Intune failed script exec

ManagementExtension-Samples/IntunePSTemplate.ps1

@@ -1,51 +1,70 @@
-# Author: Oliver Kieselbach
-# Date: 02/10/2018
-# Description: Intune Management Extension - PowerShell template with logging, error codes, and x64 PowerShell execution
-
-# The script is provided "AS IS" with no warranties.
+<#
+Version: 1.1
+Author: Oliver Kieselbach
+Script: IntunePSTemplate.ps1
+
+Description:
+Intune Management Extension - PowerShell script template with logging,
+error codes, standard error output handling and x64 PowerShell execution.
+
+Release notes:
+Version 1.0: Original published version. 
+Version 1.1: Added standard error output handling. 
+
+The script is provided "AS IS" with no warranties.
+#>
 
 $exitCode = 0
 
 if (![System.Environment]::Is64BitProcess)
 {
+     # start new PowerShell as x64 bit process, wait for it and gather exit code and standard error output
     $sysNativePowerShell = "$($PSHOME.ToLower().Replace("syswow64", "sysnative"))\powershell.exe"
 
-    # start new PowerShell as x64 bit process, wait for it and gather exit code
-    $exitCode = $(Start-Process $sysNativePowerShell -ArgumentList "-ex bypass -file `"$PSCommandPath`"" -WindowStyle Hidden -Wait -PassThru).ExitCode
+    $pinfo = New-Object System.Diagnostics.ProcessStartInfo
+    $pinfo.FileName = $sysNativePowerShell
+    $pinfo.Arguments = "-ex bypass -file `"$PSCommandPath`""
+    $pinfo.RedirectStandardError = $true
+    $pinfo.RedirectStandardOutput = $true
+    $pinfo.CreateNoWindow = $true
+    $pinfo.UseShellExecute = $false
+    $p = New-Object System.Diagnostics.Process
+    $p.StartInfo = $pinfo
+    $p.Start() | Out-Null
+
+    $exitCode = $p.ExitCode
+
+    $stderr = $p.StandardError.ReadToEnd()
+
+    if ($stderr) { Write-Error -Message $stderr }
 }
 else
 {
     # start logging to TEMP in file "scriptname".log
-    Start-Transcript -Path "$env:TEMP\$($(Split-Path $PSCommandPath -Leaf).ToLower().Replace(".ps1",".log"))"
+    Start-Transcript -Path "$env:TEMP\$($(Split-Path $PSCommandPath -Leaf).ToLower().Replace(".ps1",".log"))" | Out-Null
 
-    # === variant 1 ===
-    #
-    # => use "-ErrorAction Stop" for the command-lets and catch in case of errors
-    #
+    # === variant 1: use try/catch with ErrorAction stop -> use write-error to signal Intune failed execution
     # example:
-    #
     # try
     # {
     #     Set-ItemProperty ... -ErrorAction Stop
     # }
     # catch
-    # {
+    # {   
+    #     Write-Error -Message "Could not write regsitry value" -Category OperationStopped
     #     $exitCode = -1
     # }
 
-    # === variant 2 ===
-    #
-    # => use "-ErrorVariable err -ErrorAction SilentlyContinue" and catch error and check err variable
-    #
+    # === variant 2: ErrorVariable and check error variable -> use write-error to signal Intune failed execution
     # example:
-    #
     # Start-Process ... -ErrorVariable err -ErrorAction SilentlyContinue
     # if ($err)
     # {
+    #     Write-Error -Message "Could not write regsitry value" -Category OperationStopped
     #     $exitCode = -1
     # }
 
-    Stop-Transcript
+    Stop-Transcript | Out-Null
 }
 
 exit $exitCode