Change attribute whitelist filter syntax to match Ohai

1 files changed, 82 insertions, 0 deletions

diff --git a/lib/chef/whitelist.rb b/lib/chef/whitelist.rb
new file mode 100644
index 0000000000..ad52215f11
--- /dev/null
+++ b/lib/chef/whitelist.rb
@@ -0,0 +1,82 @@
+
+require 'chef/exceptions'
+
+class Chef
+  class Whitelist
+
+    # filter takes two arguments - the data you want to filter, and a whitelisted array
+    # of keys you want included. You can capture a subtree of the data to filter by
+    # providing a "/"-delimited string of keys. If some key includes "/"-characters,
+    # you must provide an array of keys instead.
+    #
+    # Whitelist.filter(
+    #   { "filesystem" => {
+    #       "/dev/disk" => {
+    #         "size" => "10mb"
+    #       },
+    #       "map - autohome" => {
+    #         "size" => "10mb"
+    #       }
+    #     },
+    #     "network" => {
+    #       "interfaces" => {
+    #         "eth0" => {...},
+    #         "eth1" => {...}
+    #       }
+    #     }
+    #   },
+    #   ["network/interfaces/eth0", ["filesystem", "/dev/disk"]])
+    # will capture the eth0 and /dev/disk subtrees.
+    def self.filter(data, whitelist=nil)
+      return data if whitelist.nil?
+
+      new_data = {}
+      whitelist.each do |item|
+        self.add_data(data, new_data, item)
+      end
+      new_data
+    end
+
+    private
+
+    # Walk the data has according to the keys provided by the whitelisted item
+    # and add the data to the whitelisting result.
+    def self.add_data(data, new_data, item)
+      parts = self.to_array(item)
+
+      all_data = data
+      filtered_data = new_data
+      parts[0..-2].each do |part|
+        unless all_data[part]
+          Chef::Log.warn("Could not find whitelist attribute #{item}.")
+          return nil
+        end
+
+        filtered_data[part] ||= {}
+        filtered_data = filtered_data[part]
+        all_data = all_data[part]
+      end
+
+      unless all_data[parts[-1]]
+        Chef::Log.warn("Could not find whitelist attribute #{item}.")
+        return nil
+      end
+
+      filtered_data[parts[-1]] = all_data[parts[-1]]
+      new_data
+    end
+
+    # Accepts a String or an Array, and returns an Array of String keys that
+    # are used to traverse the data hash. Strings are split on "/", Arrays are
+    # assumed to contain exact keys (that is, Array elements will not be split
+    # by "/").
+    def self.to_array(item)
+      return item if item.kind_of? Array
+
+      parts = item.split("/")
+      parts.shift if !parts.empty? && parts[0].empty?
+      parts
+    end
+
+  end
+end