configuration plugin dsl

2 files changed, 114 insertions, 0 deletions

diff --git a/lib/ohai/dsl/plugin/versionvii.rb b/lib/ohai/dsl/plugin/versionvii.rb
index fdf7fd7c..2e24322b 100644
--- a/lib/ohai/dsl/plugin/versionvii.rb
+++ b/lib/ohai/dsl/plugin/versionvii.rb
@@ -100,6 +100,47 @@ module Ohai
         def require_plugin(*args)
           Ohai::Log.warn("[UNSUPPORTED OPERATION] \'require_plugin\' is no longer supported. Please use \'depends\' instead.\nIgnoring plugin(s) #{args.join(", ")}")
         end
+
+        def configuration(option, *options)
+          return nil if plugin_config.nil? || !plugin_config.key?(option)
+          value = plugin_config[option]
+          options.each do |opt|
+            return nil unless value.key?(opt)
+            value = value[opt]
+          end
+          value
+        end
+
+        private
+        def plugin_config
+          @plugin_config ||= fetch_plugin_config
+        end
+
+        def fetch_plugin_config
+          # DMI => ["DMI"]
+          # Memory => ["", "Memory"]
+          # NetworkListeners => ["", "Network", "", "Listeners"]
+          # SSHHostKey => ["SSH", "Host", "", "Key"]
+          parts = self.name.to_s.split(/([A-Z][a-z]+)/)
+          # ["DMI"] => ["DMI"]
+          # ["", "Memory"] => ["Memory"]
+          # ["", "Network", "", "Listeners"] => ["Network", "Listeners"]
+          # ["SSH", "Host", "", "Key"] => ["SSH", "Host", "Key"]
+          parts.delete_if { |part| part.empty? }
+          # ["DMI"] => :dmi
+          # ["Memory"] => :memory
+          # ["Network", "Listeners"] => :network_listeners
+          # ["SSH", "Host", "Key"] => :ssh_host_key
+          snake_case_name = parts.map { |part| part.downcase }.join("_").to_sym
+
+          # Plugin names in config hashes are auto-vivified, so we check with
+          # key? to avoid falsely instantiating a configuration hash.
+          if Ohai.config[:plugin].key?(snake_case_name)
+            Ohai.config[:plugin][snake_case_name]
+          else
+            nil
+          end
+        end
       end
     end
   end
diff --git a/spec/unit/dsl/plugin_spec.rb b/spec/unit/dsl/plugin_spec.rb
index dc4c1681..fa2a7379 100644
--- a/spec/unit/dsl/plugin_spec.rb
+++ b/spec/unit/dsl/plugin_spec.rb
@@ -293,6 +293,79 @@ describe Ohai::DSL::Plugin::VersionVII do
     end
   end
 
+  describe "#configuration" do
+    let(:plugin) do
+      klass = Ohai.plugin(camel_name) { }
+      klass.new({})
+    end
+
+    shared_examples_for "plugin config lookup" do
+      it "returns the configuration option value" do
+        Ohai.config[:plugin][snake_name][:foo] = true
+        expect(plugin.configuration(:foo)).to eq(true)
+      end
+    end
+
+    describe "a plugin named Abc" do
+      let(:camel_name) { :Abc }
+      let(:snake_name) { :abc }
+
+      it "returns nil when the plugin is not configured" do
+        expect(plugin.configuration(:foo)).to eq(nil)
+      end
+
+      it "does not auto-vivify an un-configured plugin" do
+        plugin.configuration(:foo)
+        expect(Ohai.config[:plugin]).to_not have_key(:test)
+      end
+
+      it "returns nil when the option is not configured" do
+        Ohai.config[:plugin][snake_name][:foo] = true
+        expect(plugin.configuration(:bar)).to eq(nil)
+      end
+
+      it "returns nil when the suboption is not configured" do
+        Ohai.config[:plugin][snake_name][:foo] = { }
+        expect(plugin.configuration(:foo, :bar)).to eq(nil)
+      end
+
+      include_examples "plugin config lookup"
+
+      it "returns the configuration sub-option value" do
+        Ohai.config[:plugin][snake_name][:foo] = { :bar => true }
+        expect(plugin.configuration(:foo, :bar)).to eq(true)
+      end
+    end
+
+    describe "a plugin named ABC" do
+      let(:camel_name) { :ABC }
+      let(:snake_name) { :abc }
+
+      include_examples "plugin config lookup"
+    end
+
+    describe "a plugin named Abc2" do
+      let(:camel_name) { :Abc2 }
+      let(:snake_name) { :abc_2 }
+
+      include_examples "plugin config lookup"
+    end
+
+    describe "a plugin named AbcAbc" do
+      let(:camel_name) { :AbcXyz }
+      let(:snake_name) { :abc_xyz }
+
+      include_examples "plugin config lookup"
+    end
+
+    describe "a plugin named ABCLmnoXyz" do
+      let(:camel_name) { :ABCLmnoXyz }
+      let(:snake_name) { :abc_lmno_xyz }
+
+      include_examples "plugin config lookup"
+    end
+  end
+
   it_behaves_like "Ohai::DSL::Plugin" do
     let(:ohai) { Ohai::System.new }
     let(:plugin) { Ohai::DSL::Plugin::VersionVII.new(ohai.data) }