SCOrchDev-Exception.psm1
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<#
.SYNOPSIS Logs the details of an exception to the specified stream. .PARAMETER Exception The exception whose details should be logged. .PARAMETER Stream The stream that the exception details should be logged to. #> Function Write-Exception { Param( [Parameter(Mandatory = $True)] $Exception, [Parameter(Mandatory = $False)] [ValidateSet('Debug', 'Error', 'Verbose', 'Warning')] $Stream = 'Warning' ) $LogCommand = (Get-Command -Name "Write-$Stream") $ExceptionString = Convert-ExceptionToString -Exception $Exception & $LogCommand -Message "Exception information`r`n------`r`n$ExceptionString" -ErrorAction Continue -WarningAction Continue } <# .SYNOPSIS Returns a PSObject representing a custom exception. .PARAMETER Type The "type" of the exception. This isn't actually the type. It's a string you can use to figure out what the type would be if PowerShell actually supported custom exceptions. .PARAMETER Message A message describing the failure. .PARAMETER Property A hashtable containing other properties to propogate with the exception. All values in the hash table will be converted to strings. .EXAMPLE $Exception = New-Exception -Type 'GenericFailure' -Message 'Failing, just because' throw $Exception #> Function New-Exception { param( [Parameter(Mandatory = $True, ParameterSetName = 'Values')] [String] $Type, [Parameter(Mandatory = $True, ParameterSetName = 'Values')] [String] $Message, [Parameter(Mandatory = $False, ParameterSetName = 'Values')] [Hashtable] $Property = @{}, [Parameter(Mandatory = $True, ParameterSetName = 'ExceptionInfo')] [Object] $ExceptionInfo ) if($ExceptionInfo) { $Property = @{} ($ExceptionInfo | Get-Member | Where-Object -FilterScript { $_.MemberType -eq 'NoteProperty' }).Name | ForEach-Object -Process ` { $Property[$_] = $ExceptionInfo."$_" } } else { $Property = $Property.Clone() $Property['__CUSTOM_EXCEPTION__'] = $True $Property['Type'] = $Type $Property['FullyQualifiedErrorId'] = $Type $Property['Message'] = $Message $Property['InnerException'] = $null } return ($Property | ConvertTo-Json -Compress) } <# .SYNOPSIS Converts an exception into a string suitable for reading, including as much detail as possible that is useful for troubleshooting. .PARAMETER Exception The exception that should be converted to a string. #> Function Convert-ExceptionToString { Param( [Parameter(Mandatory = $True)] [Object] $Exception ) $ExceptionString = New-Object -TypeName 'System.Text.StringBuilder' $ExceptionInfo = Get-ExceptionInfo -Exception $Exception while($null -ne $ExceptionInfo) { # NoteProperty properties contain all the properties from the exception that # we care about, so filter on those. # # We also need to filter out the InnerException property, since nested exceptions # will be handled by the outer loop. $ExceptionInfo | Get-Member | Where-Object -FilterScript { $_.MemberType -eq 'NoteProperty' } | Where-Object -FilterScript { $_.Name -ne 'InnerException' } | ForEach-Object -Process { $PropertyName = $_.Name if(-not [String]::IsNullOrEmpty($ExceptionInfo."$PropertyName")) { $null = $ExceptionString.AppendLine("$PropertyName = $($ExceptionInfo."$PropertyName")") } } if($ExceptionInfo.InnerException) { $null = $ExceptionString.AppendLine('') $null = $ExceptionString.AppendLine('Which was raised from:') $null = $ExceptionString.AppendLine('') } $ExceptionInfo = $ExceptionInfo.InnerException } return $ExceptionString.ToString() } <# .SYNOPSIS Returns the exception information for an exception. .PARAMETER Exception The exception whose information should be returned. #> Function Get-ExceptionInfo { Param( [Parameter( Mandatory = $True, ValueFromPipeline = $True )] [AllowNull()] [Object] $Exception ) $Property = @{} $TopLevelExceptionInfo = $null $PreviousExceptionInfo = $null while($null -ne $Exception) { $CustomException = Select-CustomException -Exception $Exception if($CustomException) { $ExceptionInfo = ConvertFrom-Json -InputObject $CustomException } else { # Properties which should be included in the human-readable exception string. # The hash key is the identifier that will be used in the output string for the # hash value. # # Values will only be included if they are not null. $Property = @{ 'Type' = $Exception.GetType().FullName -replace '^Deserialized\.', '' 'Message' = Select-FirstValid -Value @($Exception.Message,$Exception.Exception.Message,$Exception.InnerException.Message,$Exception.SerializedRemoteException.Message) 'FullyQualifiedErrorId' = $Exception.FullyQualifiedErrorId 'HResult' = $Exception.HResult 'ScriptBlock' = Select-FirstValid -Value @($Exception.SerializedRemoteInvocationInfo.MyCommand.ScriptBlock,$Exception.InvocationInfo.MyCommand.ScriptBlock) 'PositionMessage' = Select-FirstValid -Value @($Exception.SerializedRemoteInvocationInfo.PositionMessage,$Exception.InvocationInfo.PositionMessage) 'ScriptStackTrace' = $Exception.ScriptStackTrace 'StackTrace' = $Exception.StackTrace 'InnerException' = $null } $ExceptionInfo = New-Object -TypeName 'PSObject' -Property $Property } if(-not $TopLevelExceptionInfo) { $TopLevelExceptionInfo = $ExceptionInfo } elseif($PreviousExceptionInfo) { $PreviousExceptionInfo.InnerException = $ExceptionInfo } $PreviousExceptionInfo = $ExceptionInfo $Exception = Select-FirstValid -Value $Exception.Exception, $Exception.InnerException } try { Add-Member -InputObject $TopLevelExceptionInfo ` -MemberType NoteProperty ` -Name 'PSCallStack' ` -Value ((Get-PSCallStack) | Where-Object -FilterScript { $_.ScriptName -notlike '*-Exception.psm1' } | ConvertTo-JSON) } catch { Write-Debug -Message 'Error adding call stack' } return $TopLevelExceptionInfo } <# .SYNOPSIS Tests whether or not the exception is a custom exception as returned by New-Exception or thrown by Throw-Exception. If it is, returns the custom exception string. Otherwise it returns $False. .PARAMETER Exception The exception which should be tested. #> Function Select-CustomException { param( [Parameter(Mandatory = $True)] [Object] $Exception ) $TestString = @(($Exception -as [String]), ($Exception.Message -as [String])) Foreach($_TestString in $TestString) { try { $ExceptionObject = ConvertFrom-Json -InputObject $_TestString if($ExceptionObject.'__CUSTOM_EXCEPTION__') { return $_TestString } } catch [System.ArgumentException] { Write-Debug -Message 'Non custom error found' } } } <# .SYNOPSIS Attepts to select the relevant exception that has been thrown inside an invoked script block. .DESCRIPTION Invoking a script block that throws an exception will result in an object where the exception we actually care about is hidden in an InnerException property. The exception of interest may not always be nested at the same depth (i.e. you may need to do $Exception.InnerException or $Exception.InnerException. InnerException to get what you want). This cmdlet attempts to remove the crud by filtering out select exception types. .PARAMETER RootException The exception that was thrown by an invoked script block. #> Function Select-RelevantException { Param( [Parameter(Mandatory = $True)] $RootException ) $InnerException = $RootException.Exception $BlacklistedExceptions = [System.Management.Automation.ErrorRecord], [System.Management.Automation.MethodInvocationException], [System.Management.Automation.CmdletInvocationException] While(($InnerException.GetType() -in $BlacklistedExceptions) -and $InnerException.InnerException) { $InnerException = $InnerException.InnerException } Return $InnerException } <# .SYNOPSIS Throws a custom exception. .PARAMETER Type The "type" of the exception. This isn't actually the type. It's a string you can use to figure out what the type would be if PowerShell actually supported custom exceptions. Damnit, PowerShell. Use a switch block or similar in your catch statement to work with this. .PARAMETER Message A message describing the failure. .EXAMPLE try { Throw-Exception -Type 'GenericFailure' -Message 'Failing, just because' } catch { switch -CaseSensitive ((Get-ExceptionInfo -Exception $_).Type) { 'GenericFailure' { Write-Warning -Message 'Look, a generic failure' } 'SomeOtherFailure' { Write-Warning -Message 'Look, a failure we will never see' } default { Write-Warning -Message 'I am handling ALL the failures!' } } } #> Function Throw-Exception { param( [Parameter(Mandatory = $True, ParameterSetName = 'Values')] [String] $Type, [Parameter(Mandatory = $True, ParameterSetName = 'Values')] [String] $Message, [Parameter(Mandatory = $False, ParameterSetName = 'Values')] [Hashtable] $Property = @{}, [Parameter(Mandatory = $True, ParameterSetName = 'ExceptionInfo')] [Object] $ExceptionInfo ) if($ExceptionInfo) { throw New-Exception -ExceptionInfo $ExceptionInfo } else { throw New-Exception -Type $Type -Message $Message -Property $Property } } Export-ModuleMember -Function * -Verbose:$False |