在厨师运行期间如何重新加载环境变量？

Question

I am automating some provisioning on windows using chef-solo. I have an issue with a recipe that needs an environment setup indirectly by a previous recipe (concretely, I am installing visual studio in recipe 1, and recipe 2 needs to start in a new environment to access the variables set up by recipe1).

As far as I know, there is no way to tell chef to 'reload an environment' ? What would be the best way to achieve this ? At worse, if that makes it easier, I don't mind rebooting either, as long as the reboot and chef continuning the provisioning is entirely automated.

Answer 1

You could possibly run a ruby block and add the new environment variables to the current environment variables:

ruby_block "get new env variables" do
  block do
    new_env = `cmd.exe /C set`
    #do some parsing magic, then set the new_env
    ENV = parsed_env
  end
 end

I haven't tested this, but it may get you on the right track.

Answer 2

Chocolatey uses Refreshenv script for the very same task, reloading environment variables from Registry.

I've ported this script to Ruby (licensed under Apache 2.0 license):

require 'win32/registry'

def get_reg_env(hkey, subkey, &block)
  Win32::Registry.open(hkey, subkey) do |reg|
    reg.each_value do |name|
      value = reg.read_s_expand(name)
      if block && ENV.key?(name)
        ENV[name] = block.call(name, ENV[name], value)
      else
        ENV[name] = value
      end
    end
  end
end

def refresh_env
  get_reg_env(Win32::Registry::HKEY_LOCAL_MACHINE, 'System\CurrentControlSet\Control\Session Manager\Environment')
  get_reg_env(Win32::Registry::HKEY_CURRENT_USER, 'Environment') do |name, old_value, new_value|
    if name.upcase == 'PATH'
      old_value || File::PATH_SEPARATOR || new_value
    else
      new_value
    end
  end
end

You put it in libraries dir and use it in a recipe like this:

ruby_block 'refreshenv' do
  block do
    refresh_env
  end
  action :nothing
end

chocolatey_package 'visualstudio2017buildtools' do
  notifies :run, 'ruby_block[refreshenv]', :immediately
end

Maybe somebody could wrap it in a cookbook.

For more cross-platform way you could also take a look at dotenv gem .