PowerShell Try, Catch, custom terminating error message

Question

Is there a way to customize the error message of a terminating error?

In the example below I would like to just end up with one Try section and collect all errors in one Catch section by combining both script blocks. My problem is that the $error generated by Import-csv is not descriptive enough and I would like to have the text Failed CSV-File import c:\test.csv within the $error message.

Thank you for your advise.

Script block 1

Try {
    $File = (Import-Csv -Path c:\test.csv)
}
Catch {
    throw $error[0].Exception.Message | Send-Mail $ScriptAdmin "FAILED CSV-File import"
}

Script block 2

try {
    if(!(Test-Path $LogFolder -PathType Container)) {throw "Can't find the log folder: '$LogFolder'"}
    $Credentials = Import-Credentials $UserName $PasswordFile
}
catch {
    throw $Error[0].Exception.Message | Send-Mail $ScriptAdmin "FAILURE"
}

Workaround

A possible solution would be to check first with test-path if the import file exists and then create a throw with a customized message. But I would like to know if it's possible to handle it in one line of code without using test-path first.

Best solution (thanks to mjolinor):

try {
    $File = (Import-Csv -Path $ImportFile -Header "A", "B", "C", "D" | Where { $_.A -NotLike "#*" })
    if(!(Test-Path $LogFolder -PathType Container)) {throw "Can't find the log folder: '$LogFolder'"}
    $Credentials = Import-Credentials $UserName $PasswordFile
}
catch {
    Switch -Wildcard ($Error[0].Exception)
        {
           "*$ImportFile*"
           { $FailType = "FAILED CSV-File import" }

           "*$LogFolder*"
           { $FailType = "FAILED Log folder not found" }

           "*Import-Credentials*"
           { $FailType = "FAILED Credential import" }

           Default
           { $FailType = "FAILED Unrecognized error" }

         }
       Write-Warning $Error[0].Exception.Message
       throw $Error[0].Exception.Message | Send-Mail $ScriptAdmin $FailType
}

Make sure that your advanced-function which you created (like Import-Credentials above) contains the function name in the throw section. So we can filter it out in the catchblock.

mjolinor · Accepted Answer · 2014-07-27 21:34:55Z

3

Something like this, maybe?

Try {
      $File = (Import-Csv -Path c:\test.csv)

      if(!(Test-Path $LogFolder -PathType Container)) 
      { throw "Can't find the log folder: '$LogFolder'" }

      $Credentials = Import-Credentials $UserName $PasswordFile

      }

catch {
        Switch -Wildcard ($Error[0].CategoryInfo)
        {
           '*[Import-CSV]*' 
           { $FailType = 'Import CSV failed' }

           '*[Test-Path]*'
           { $FailType = 'LogFolder not found' }

           '*[Import-Credentials]*'
           { $FailType = 'Credential import failed' }

           Default
           { $FailType = 'Unrecognized error' }

         }

         $Error[0].Exception.Message | Send-Mail $ScriptAdmin $FailType

       }

Edit (for some reason I'm not able to post a comment):

I should have specified that it wasn't tested, and was intended more as a pattern than a finished solution, and it seems to have done what it was intended to do.

@BartekB - I habitually use $Error[0] instead of $_ because it seems more explicit and intuitive to read, and less likely to be misunderstood by someone less experienced who might inherit the code later.

edited Jul 27, 2014 at 21:34

answered Jul 26, 2014 at 12:11

mjolinor

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5 Comments

DarkLite1 Over a year ago

Thank you mjolinor, that's exactly what I'm looking for. However, it errors out with The specified wildcard character pattern is not valid: *[Import-CSV]* although $error[0] contains the matching word: + CategoryInfo : OpenError: (:) [Import-Csv], FileNotFoundException`

DarkLite1 Over a year ago

Works like a charm when removing the brackets [], from '*[Import-CSV]*' to '*Import-CSV*'. Thanks again, this helped me a lot :)

DarkLite1 Over a year ago

For Test-Path this doesn't work, because the field $Error[0].CategoryInfodoesn't contain the word Test-Path as it's not in the throw. Is there a way to set the CategoryInfo from within throw?

DarkLite1 Over a year ago

Found it, the best way to do it (thanks to your help) is using $Error[0].Exception and then put the variables used as wildcards, like *$ImportFile* and *$LogFolder* and others. I'll mark your answer as Solved. Thanks again :) I'll update the post with the full solution to for others.

BartekB Over a year ago

BTW: any reason why you use $Error[0] instead of $_? Latter (by definition) should contain thrown error.

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