Writing errors to CSV in Powershell - powershell

Question

$csv = Get-Content c:\users\user\downloads\OutofContact.csv
foreach ($computer in $csv)
{
try{
$report = New-Object -TypeName PSObject -Property #{
ComputerName = (Resolve-DnsName $computer).Name
IPAddress = (Resolve-DnsName $computer).IPAddress
}
$report | select-object -Property ComputerName, IPAddress | Export-Csv -Path Results.csv -notype -append
}catch{
Write-Error "$computer not found" | Export-Csv -Path Results.csv -notype -append
}
}
I'm using the above code to check the DNS entries for a list of machines. Some of the machines do not exist in DNS and will throw an error. I want those machines to write the error into the CSV, however they just show up as blank rows.
How can I get the errors to write to the CSV as well?

Answer 1

I would refactor and optimize duplicate calls, and only add one object at the end...
Something like this:
#$csv = Get-Content c:\users\user\downloads\OutofContact.csv
# test
$csv = #('localhost', 'doesnotexist', 'localhost', 'doesnotexist')
$allReports = [System.Collections.ArrayList]::new()
foreach ($computer in $csv)
{
$report = [pscustomobject]#{
'ComputerName' = $computer
'IPAddress' = 'none'
'Status' = 'none'
}
try
{
# this can return multiple entries/ipaddresses
$dns = Resolve-DnsName $computer -ErrorAction Stop | Select -First 1
$report.ComputerName = $dns.Name
$report.IPAddress = $dns.IPAddress
$report.Status = 'ok'
}
catch
{
Write-Error "$computer not found"
}
finally
{
$null = $allReports.Add($report);
}
}
# write to csv file once...
$allReports | Export-Csv -Path c:\temp\Results.csv -NoTypeInformation #??? keep this? -Append
You will want to walk through the code and debug and change to your specific requirements.