Add ohai config context and deprecate top-level config.

1 files changed, 97 insertions, 15 deletions

diff --git a/lib/ohai/config.rb b/lib/ohai/config.rb
index 4c51e08a..988c2328 100644
--- a/lib/ohai/config.rb
+++ b/lib/ohai/config.rb
@@ -1,6 +1,7 @@
 #
 # Author:: Adam Jacob (<adam@opscode.com>)
-# Copyright:: Copyright (c) 2008 Opscode, Inc.
+# Author:: Claire McQuin (<claire@chef.io>)
+# Copyright:: Copyright (c) 2008-2015 Chef Software, Inc.
 # License:: Apache License, Version 2.0
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -16,28 +17,109 @@
 # limitations under the License.
 #
 
-require 'mixlib/config'
 require 'ohai/log'
+require 'chef-config/logger'
+
+ChefConfig::Logger = Ohai::Log
+
+require 'chef-config/config'
 
 module Ohai
+  Config = ChefConfig::Config
+
+  # Reopens ChefConfig::Config to add Ohai configuration settings.
+  # see: https://github.com/chef/chef/blob/master/lib/chef/config.rb
   class Config
-    extend Mixlib::Config
-
-    # from chef/config.rb, should maybe be moved to mixlib-config?
-    def self.platform_specific_path(path)
-      if RUBY_PLATFORM =~ /mswin|mingw|windows/
-        # turns /etc/chef/client.rb into C:/chef/client.rb
-        path = File.join(ENV['SYSTEMDRIVE'], path.split('/')[2..-1])
-        # ensure all forward slashes are backslashes
-        path.gsub!(File::SEPARATOR, (File::ALT_SEPARATOR || '\\'))
+    # These methods need to be defined before they are used as config defaults,
+    # otherwise they will get method_missing'd to nil.
+    private
+    def self.default_hints_path
+      [ platform_specific_path('/etc/chef/ohai/hints') ]
+    end
+
+    def self.default_plugin_path
+      [ File.expand_path(File.join(File.dirname(__FILE__), 'plugins')) ]
+    end
+
+    public
+    # Copy deprecated configuration options into the ohai config context.
+    def self.merge_deprecated_config
+      [ :hints_path, :plugin_path ].each do |option|
+        if has_key?(option) && send(option) != send("default_#{option}".to_sym)
+          Ohai::Log.warn(option_deprecated(option))
+        end
       end
-      path
+
+      ohai.merge!(configuration)
     end
 
+    # Keep "old" config defaults around so anyone calling Ohai::Config[:key]
+    # won't be broken. Also allows users to append to configuration options
+    # (e.g., Ohai::Config[:plugin_path] << some_path) in their config files.
+    default :disabled_plugins, []
+    default :hints_path, default_hints_path
     default :log_level, :info
     default :log_location, STDERR
-    default :plugin_path, [ File.expand_path(File.join(File.dirname(__FILE__), 'plugins'))]
-    default :disabled_plugins, []
-    default(:hints_path) { [ platform_specific_path('/etc/chef/ohai/hints') ] }
+    default :plugin_path, default_plugin_path
+
+    # Log deprecation warning when a top-level configuration option is set.
+    # TODO: Should we implement a config_attr_reader so that deprecation
+    # warnings will be generatd on read?
+    [
+      :directory,
+      :disabled_plugins,
+      :log_level,
+      :log_location,
+      :version
+    ].each do |option|
+      # https://docs.chef.io/config_rb_client.html#ohai-settings
+      # hints_path and plugin_path are intentionally excluded here; warnings for
+      # setting these attributes are generated in merge_deprecated_config since
+      # append (<<) operations bypass the config writer.
+      config_attr_writer option do |value|
+        # log_level and log_location are common configuration options for chef
+        # and other chef applications. When configuration files are read there
+        # is no distinction between log_level and Ohai::Config[:log_level] and
+        # we may emit a false deprecation warning. The deprecation warnings for
+        # these settings reflect that possibility.
+        # Furthermore, when the top-level config settings are removed we will
+        # need to ensure that Ohai.config[:log_level] can be set by writing
+        # log_level in a configuration file for consistent behavior with chef.
+        deprecation_warning = [ :log_level, :log_location ].include?(value) ?
+          option_might_be_deprecated(option) : option_deprecated(option)
+        Ohai::Log.warn(deprecation_warning)
+        value
+      end
+    end
+
+    config_context :ohai do
+      default :disabled_plugins, []
+      default :hints_path, Ohai::Config.default_hints_path
+      default :log_level, :info
+      default :log_location, STDERR
+      default :plugin_path, Ohai::Config.default_plugin_path
+    end
+
+    private
+    def self.option_deprecated(option)
+      <<-EOM.chomp!.gsub("\n", " ")
+Ohai::Config[:#{option}] is set. Ohai::Config[:#{option}] is deprecated and will
+be removed in future releases of ohai. Use ohai.#{option} in your configuration
+file to configure :#{option} for ohai.
+EOM
+    end
+
+    def self.option_might_be_deprecated(option)
+      option_deprecated(option) + <<-EOM.chomp!.gsub("\n", " ")
+ If your configuration file is used with other applications which configure
+:#{option}, and you have not configured Ohai::Config[:#{option}], you may
+disregard this warning.
+EOM
+    end
+  end
+
+  # Shortcut for Ohai::Config.ohai
+  def self.config
+    Config::ohai
   end
 end