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PowerShell error handling best practices

Question on PowerShell error handling. Which method is 'better' and why?

Using Try/Catch to handle any errors for Do-Something

try {
    Do-Something -ErrorAction 'Stop'
}
catch {
    $errormessage = $_.Exception.Message
    Write-Verbose "An error occurred: $errormessage"
}

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Using an If statement to handle errors for Do-Something

if (Do-Something) {
    Do-SomethingElse
}
else {
    $errormessage = $_.Exception.Message
    Write-Verbose "An error occurred: $errormessage"
}

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SOLUTION

Bell TechLogix

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SOLUTION

Qlemo

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Jason Crawford

ASKER

@Qlemo here's what prompted the question - I had these two sections of my script sitting right next to each other and I honestly couldn't nail down why I used try/catch for Disable-MailContact whereas I used an if statement for Get-MailContact:

try {
    Disable-MailContact $user -Confirm:$false -ErrorAction 'stop'
}
catch {
    $errormessage = $_.Exception.Message
    Write-Verbose "An error occurred: $errormessage"
}

if (!(Get-MailContact $user)) {
    if (Enable-MailUser $aduser.SamAccountName -ExternalEmailAddress $contact.ExternalEmailAddress) {
        Set-MailUser $user -EmailAddresses @{add=$contact.emailaddresses}
        Set-MailUser $user -EmailAddresses @{add=$legdn}
    }
}

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Is there a better way to do this?

Bell TechLogix

what is the result you are getting, and what is the result you are expecting?

Jason Crawford

ASKER

The specific results don't matter I'm just asking from a best practices point of view for my own education.

Bell TechLogix

The best answer is try the (Try,Catch) but if it doesn't work in your scenario then move to the next option, and that's checking the results, and if that doesn't work, then pull the source a second time and verify you have changed what you wanted.

ASKER CERTIFIED SOLUTION

Qlemo

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Jason Crawford

ASKER

That's an interesting thought though. For instance if I wanted to take action when a MailContact isn't found I could catch the specific error generated for object not found:

try {
    Get-MailContact $_
}

catch [ManagementObjectNotFoundException] {
    Enable-MailUser $aduser.samaccountname -ExternalEmailAddress $_
    Set-MailUser $_ -EmailAddresses @{add=$contact.emailaddresses}
}

catch {
    Write-Verbose "An error occurred: $($error[0].exception.message)"
}

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Thanks for helping me talk this through.