how do I use Regex in powershell commands with ruby using puppet - ruby

Question

I need to create a fact in puppet to get which versions of .netcore are installed in the servers.
Facter.add('common_dotnetcore_version') do
confine :kernel => 'windows'
powershell = 'C:\Windows\system32\WindowsPowershell\v1.0\powershell.exe'
setcode do
dotnetVersion = Hash.new
if Facter::Util::Resolution.which('dotnet')
dotNetList = Facter::Core::Execution.exec(%Q{#{powershell} -command "(((dotnet --list-runtimes ) -replace '(?!\d*\.\d*)[A-Za-z([():\]\\)]') | select -Unique)"})
dotNetList.each_line { |line| dotnetVersion[line] = true }
end
dotnetVersion
end
end
please note that when I run this command in PowerShell
(((dotnet --list-runtimes ) -replace '(?!\d*\.\d*)[A-Za-z([():\]\\)]') | select -Unique)
I got this output:
.. 2.1.26 ..
.. 2.1.28 ..
.. 3.1.13 ..
.. 3.1.15 ..
.. 5.0.4 ..
.. 5.0.6 ..
But when its executed by Puppet I got this output:
Microsoft.AspNetCore.All 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
It's not doing the -replace with the Regex
Does anyone know why Puppet does not recognize the Regex and | select -Unique?

Answer 1

The problem is that backslashes inside a Ruby %Q{...} quoted string have a meaning. For example, %Q{\n} is a newline. So the backslashes in your regex are being interpreted by the %Q{...} string before they get to PowerShell.
If you look at the string:
puts %Q{'(?!\d*\.\d*)[A-Za-z([():\]\\)]'}
# '(?!d*.d*)[A-Za-z([():]\)]'
you'll see that the backslashes are going away.
The easiest thing to do is to escape all the backslashes by doubling them:
dotNetList = Facter::Core::Execution.exec(%Q{#{powershell} -command "(((dotnet --list-runtimes ) -replace '(?!\\d*\\.\\d*)[A-Za-z([():\\]\\\\)]') | select -Unique)"})