How Can I handle Errors in PS

Question

I'm trying to catch the error from service restart using function. The issue Im having that catch is not doing anything through the script.

Function Service_Restart ($Servers, $Service){
    try {
    Write-Host "$CurrentDateTime - Restarting Service $Service on Servers $Servers"
    ForEach($Serv in $Servers){
        

            Get-Service -ComputerName $Serv -Name $Service | Restart-Service
            
        }
        
    
    } catch [System.ServiceProcess.ServiceController] { 
        
        $error[0].Exception

        
}

Service_Restart Server1 ServiceName

I'm expecting to see an one line error not the full stack, however I see the entire error.

What I like to see as an example

Restart-Service : Service 'Adobe Acrobat Update Service (AdobeARMservice)' cannot be stopped due to the following error: Cannot open AdobeARMservice service on computer 'Localhost'.

However I'm seeing

Restart-Service : Service 'Adobe Acrobat Update Service (AdobeARMservice)' cannot be stopped due to the following error: Cannot open AdobeARMservice service on computer 'Localhost'.
At C:\user\UTILS_Version3.ps1:48 char:62
+ ...      Get-Service -ComputerName $Serv -Name $Service | Restart-Service
+                                                           ~~~~~~~~~~~~~~~
    + CategoryInfo          : CloseError: (System.ServiceProcess.ServiceController:ServiceController) [Restart-Service], ServiceCommandException
    + FullyQualifiedErrorId : CouldNotStopService,Microsoft.PowerShell.Commands.RestartServiceCommand

If I run $error[0].Exception manually I get the result I'm looking for but not through the function.

PS C:\Users\>  $error[0].Exception

Service 'Adobe Acrobat Update Service (AdobeARMservice)' cannot be stopped due to the following error: Cannot open AdobeARMservice service on computer '127.0.0.1'.
PS C:\Users\>

In the `catch` block, `$_` is the exception object. Try `$_.Exception`. — AdminOfThings, Jan 27 '21 at 14:56
Your exception type is wrong. It needs to be `[Microsoft.PowerShell.Commands.ServiceCommandException]` — AdminOfThings, Jan 27 '21 at 15:03
I tried that too, same result and getting the whole error stack instead one liner. — Ahmad, Jan 27 '21 at 15:08
AdminOfThings' answer contains good additional information on how to identify the specific exception type to catch, but the primary problem - expecting a _non-terminating_ error to be caught with `try` / `catch` - is what makes this question a duplicate. — mklement0, Jan 27 '21 at 16:54

score 1 · Accepted Answer · answered Jan 27 '21 at 15:12

When using try and catch, you must be working with terminating errors. Since some errors are non-terminating, you can force them to be terminating. To ensure your commands generate terminating errors, you can use the common parameter -ErrorAction Stop. Alternatively, you can set $ErrorActionPreference = 'Stop' and all commands within the session will implicitly apply -ErrorAction Stop.

In a catch block, $_ or $PSItem is the caught ErrorRecord object. When handling a specific error, it is best to use the error type's full name. You can retrieve that with $_.Exception.GetType().Fullname in the catch block or $error[0].Exception.GetType().Fullname outside of try {} catch {}.

Putting this all together, you can do the following:

try {
    Get-Service -ComputerName $Serv -Name $Service -ErrorAction Stop |
        Restart-Service -ErrorAction Stop
} catch [Microsoft.PowerShell.Commands.ServiceCommandException] {
    $_.Exception
}

See About Try Catch Finally for more information.

How Can I handle Errors in PS

1 Answers1