how do I use the output of a shell command as a conditional value in a recipe

Question

This is what I want to do:

1. First check if a cert is installed on the server
2. If not installed copy down the pfx to a temp location
3. Install the pfx
4. delete the pfx

How do I do this in a recipe?

Here is some semi-pseudo code:

unless "ls Cert:\LocalMachine\My\ | ?{$_.Subject -like '*#{cert_name}*'}"

  cookbook_file cert_temp_path do
    source cert_name
  end

  windows_certificate "c:/test/mycert.pfx" do
      pfx_password    'MyPass!'
  end

end

How do I execute that line of PS code? Can I call the powershell_script resource directly somehow?

Answer 1

This isn't how you would use Chef. Chef requires you rethink in terms of convergent behavior, rather than procedural steps. In this case, your end state would be:

1. Cookbook file for the cert is copied to cache path.
2. Cert is imported.

Trust that cookbook_file and windows_certificate are idempotent and convergent themselves, meaning they will take care of only acting when needed.

Answer 2

This is what I needed: Chef NOT_IF and ONLY_IF validation issue in Windows recipes

I needed the guard_interpreter setting.

Adding this to any resource calls that work with the pfx solve my issue:

guard_interpreter :powershell_script
not_if "My powershell code"