Chapters/handling-errors/snippets.ps1
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# notice error behavior Get-Service -Name BITS,Nobody,WinRM # try each in turn Get-Service -Name BITS,Nobody,WinRM -EA Continue Get-Service -Name BITS,Nobody,WinRM -EA SilentlyContinue Get-Service -Name BITS,Nobody,WinRM -EA Inquire Get-Service -Name BITS,Nobody,WinRM -EA Stop # moving from this... Write-Verbose "Connecting to $computer over $protocol" $session = New-CimSession -ComputerName $computer ` -SessionOption $option # to this... Write-Verbose "Connecting to $computer over $protocol" $params = @{'ComputerName'=$Computer 'SessionOption'=$option 'ErrorAction'='Stop'} $session = New-CimSession @params # observe structure - will not execute as-is PROCESS { foreach ($computer in $computername) { if ($protocol -eq 'Dcom') { $option = New-CimSessionOption -Protocol Dcom } else { $option = New-CimSessionOption -Protocol Wsman } Try { Write-Verbose "Connecting to $computer over $protocol" $params = @{'ComputerName'=$Computer 'SessionOption'=$option 'ErrorAction'='Stop'} $session = New-CimSession @params Write-Verbose "Querying from $computer" $os_params = @{'ClassName'='Win32_OperatingSystem' 'CimSession'=$session} $os = Get-CimInstance @os_params $cs_params = @{'ClassName'='Win32_ComputerSystem' 'CimSession'=$session} $cs = Get-CimInstance @cs_params $sysdrive = $os.SystemDrive $drive_params = @{'ClassName'='Win32_LogicalDisk' 'Filter'="DeviceId='$sysdrive'" 'CimSession'=$session} $drive = Get-CimInstance @drive_params $proc_params = @{'ClassName'='Win32_Processor' 'CimSession'=$session} $proc = Get-CimInstance @proc_params | Select-Object -first 1 Write-Verbose "Closing session to $computer" $session | Remove-CimSession Write-Verbose "Outputting for $computer" $obj = [pscustomobject]@{'ComputerName'=$computer 'OSVersion'=$os.version 'SPVersion'=$os.servicepackmajorversion 'OSBuild'=$os.buildnumber 'Manufacturer'=$cs.manufacturer 'Model'=$cs.model 'Procs'=$cs.numberofprocessors 'Cores'=$cs.numberoflogicalprocessors 'RAM'=($cs.totalphysicalmemory / 1GB) 'Arch'=$proc.addresswidth 'SysDriveFreeSpace'=$drive.freespace} Write-Output $obj } Catch { } #try/catch } #foreach } #PROCESS # observe catch behavior - will not execute as-is } Catch { Write-Warning "FAILED $computer on $protocol" # Did we specify protocol fallback? # If so, try again. If we specified logging, # we won't log a problem here - we'll let # the logging occur if this fallback also # fails If ($ProtocolFallback) { If ($Protocol -eq 'Dcom') { $newprotocol = 'Wsman' } else { $newprotocol = 'Dcom' } #if protocol Write-Verbose "Trying again with $newprotocol" $params = @{'ComputerName'=$Computer 'Protocol'=$newprotocol 'ProtocolFallback'=$False} If ($PSBoundParameters.ContainsKey('LogFailuresToPath')){ $params += @{'LogFailuresToPath'=$LogFailuresToPath} } #if logging Get-MachineInfo @params } #if protocolfallback # if we didn't specify fallback, but we # did specify logging, then log the error, # because we won't be trying again If (-not $ProtocolFallback -and $PSBoundParameters.ContainsKey('LogFailuresToPath')){ Write-Verbose "Logging to $LogFailuresToPath" $computer | Out-File $LogFailuresToPath -Append } # if write to log } #try/catch # pseudo-code Try { $ErrorActionPreference = "Stop" # run something that doesn't have -ErrorAction $ErrorActionPreference = "Continue" } Catch { # ... } # pseudo-code Try { # something here generates an exception } Catch [Exception.Type.One] { # deal with that exception here } Catch [Exception.Type.Two] { # deal with the other exception here } Catch { # deal with anything else here } Finally { # run something else } |