Maybe something closer to https://github.com/johnbellone/chef-provisioning-cookbook/blob/master/recipes/fog.rb#L19-L25 would be better? You'd fail faster. I'd look at how other cookbooks install fog, and see what the common pattern is. Additionally, I don't see any cookbook on Supermarket that installs the fog gem -- this could totally be a simple community cookbook that you could also write.
Maybe something closer to https://github.com/johnbellone/chef-provisioning-cookbook/blob/master/recipes/fog.rb#L19-L25 would be better? You'd fail faster. I'd look at how other cookbooks install fog, and see what the common pattern is. Additionally, I don't see any cookbook on Supermarket that installs the fog gem -- this could totally be a simple community cookbook that you could also write.