Merge pull request #278 from opscode/OHAI-546

OHAI-546: cannot print specified attributes on the command line 

3 files changed, 96 insertions, 6 deletions

diff --git a/lib/ohai/provides_map.rb b/lib/ohai/provides_map.rb
index c2da2124..18a76d25 100644
--- a/lib/ohai/provides_map.rb
+++ b/lib/ohai/provides_map.rb
@@ -60,19 +60,35 @@ module Ohai
       plugins.uniq
     end
 
-    # gather plugins providing each of the attributes listed along
-    # with providers of subattributes
+    # This function is used to fetch the plugins for the attributes specified
+    # in the CLI options to Ohai.
+    # It first attempts to find the plugins for the attributes
+    # or the sub attributes given.
+    # If it can't find any, it looks for plugins that might
+    # provide the parents of a given attribute and returns the
+    # first parent found.
     def deep_find_providers_for(attributes)
       plugins = []
       attributes.each do |attribute|
         attrs = select_subtree(@map, attribute)
-        raise Ohai::Exceptions::AttributeNotFound, "No such attribute: \'#{attribute}\'" unless attrs
+
+        unless attrs
+          attrs = select_closest_subtree(@map, attribute)
+
+          unless attrs
+            raise Ohai::Exceptions::AttributeNotFound, "No such attribute: \'#{attribute}\'"
+          end
+        end
+
         collect_plugins_in(attrs, plugins)
       end
+
       plugins.uniq
     end
 
-    # gather plugins providing each of the attributes listed, or the
+    # This function is used to fetch the plugins from
+    # 'depends "languages"' statements in plugins.
+    # It gathers plugins providing each of the attributes listed, or the
     # plugins providing the closest parent attribute
     def find_closest_providers_for(attributes)
       plugins = []
diff --git a/spec/unit/provides_map_spec.rb b/spec/unit/provides_map_spec.rb
index 3db88d21..9fa9a8f5 100644
--- a/spec/unit/provides_map_spec.rb
+++ b/spec/unit/provides_map_spec.rb
@@ -116,20 +116,25 @@ describe Ohai::ProvidesMap do
     end
   end
 
-  describe "when looking for attribute and subattribute providers" do
+  describe "when looking for providers of attributes specified in CLI" do
     before do
       provides_map.set_providers_for(plugin_1, ["cat/whiskers"])
       provides_map.set_providers_for(plugin_2, ["cat/paws", "cat/paws/toes"])
       provides_map.set_providers_for(plugin_3, ["cat/mouth/teeth"])
     end
 
-    it "should find providers for subattributes even when the attribute doesn't have a provider" do
+    it "should find providers for subattributes if any exists when the attribute doesn't have a provider" do
       providers = provides_map.deep_find_providers_for(["cat"])
       expect(providers).to have(3).plugins
       expect(providers).to include(plugin_1)
       expect(providers).to include(plugin_2)
       expect(providers).to include(plugin_3)
     end
+
+    it "should find providers for the first parent attribute when the attribute or any subattributes doesn't have a provider" do
+      providers = provides_map.deep_find_providers_for(["cat/paws/front"])
+      expect(providers).to eq([plugin_2])
+    end
   end
 
   describe "when looking for the closest providers" do
diff --git a/spec/unit/system_spec.rb b/spec/unit/system_spec.rb
index ff5dcbbf..0ab66ab4 100644
--- a/spec/unit/system_spec.rb
+++ b/spec/unit/system_spec.rb
@@ -619,4 +619,73 @@ EOF
 
     end
   end
+
+  describe "when running ohai for specific attributes" do
+    when_plugins_directory "contains v7 plugins" do
+      with_plugin("languages.rb", <<-E)
+        Ohai.plugin(:Languages) do
+          provides 'languages'
+
+          collect_data do
+            languages Mash.new
+          end
+        end
+      E
+
+      with_plugin("english.rb", <<-E)
+        Ohai.plugin(:English) do
+          provides 'languages/english'
+
+          depends 'languages'
+
+          collect_data do
+            languages[:english] = Mash.new
+            languages[:english][:version] = 2014
+          end
+        end
+      E
+
+      with_plugin("french.rb", <<-E)
+        Ohai.plugin(:French) do
+          provides 'languages/french'
+
+          depends 'languages'
+
+          collect_data do
+            languages[:french] = Mash.new
+            languages[:french][:version] = 2012
+          end
+        end
+      E
+
+      before do
+        @original_config = Ohai::Config[:plugin_path]
+        Ohai::Config[:plugin_path] = [ path_to(".") ]
+      end
+
+      after do
+        Ohai::Config[:plugin_path] = @original_config
+      end
+
+      it "should run all the plugins when a top level attribute is specified" do
+        ohai.all_plugins("languages")
+        ohai.data[:languages][:english][:version].should == 2014
+        ohai.data[:languages][:french][:version].should == 2012
+      end
+
+      it "should run the first parent when a non-existent child is specified" do
+        ohai.all_plugins("languages/english/version")
+        ohai.data[:languages][:english][:version].should == 2014
+        ohai.data[:languages][:french].should be_nil
+      end
+
+      it "should be able to run multiple plugins" do
+        ohai.all_plugins(["languages/english", "languages/french"])
+        ohai.data[:languages][:english][:version].should == 2014
+        ohai.data[:languages][:french][:version].should == 2012
+      end
+
+    end
+  end
+
 end