Ohai::Runner class for running plugins, add run_plugins to Ohai::System to run loaded plugins

1 files changed, 257 insertions, 0 deletions

diff --git a/spec/unit/runner_spec.rb b/spec/unit/runner_spec.rb
index 3ad237d2..51fca2b3 100644
--- a/spec/unit/runner_spec.rb
+++ b/spec/unit/runner_spec.rb
@@ -16,3 +16,260 @@
 # See the License for the specific language governing permissions and
 # limitations under the License
 #
+
+require File.expand_path(File.dirname(__FILE__) + '/../spec_helper.rb')
+
+describe Ohai::Runner, "run_plugin" do
+  describe "when running a plugin with no dependencies, Ohai::Runner" do
+    before(:each) do
+      @ohai = Ohai::System.new
+      @runner = Ohai::Runner.new(@ohai, true)
+
+      klass = Ohai.plugin { provides("thing"); collect_data { thing(Mash.new) } }
+      @plugin = klass.new(@ohai, "/tmp/plugins/thing.rb")
+    end
+
+    it "should not find dependencies" do
+      @runner.should_receive(:fetch_providers).with([]).and_return([])
+      @runner.run_plugin(@plugin)
+    end
+
+    it "should run the plugin" do
+      @runner.run_plugin(@plugin)
+      @plugin.has_run?.should be_true
+    end
+
+    it "should add plugin data to Ohai::System.data" do
+      @runner.run_plugin(@plugin)
+      @ohai.data.should have_key(:thing)
+      @ohai.data[:thing].should eql({})
+    end
+  end
+
+  describe "when running a plugin with one dependency" do
+    before(:each) do
+      @ohai = Ohai::System.new
+      @runner = Ohai::Runner.new(@ohai, true)
+    end
+
+    describe "when the dependency does not exist" do
+      before(:each) do
+        klass = Ohai.plugin { provides("thing"); depends("other_thing"); collect_data { thing(other_thing) } }
+        @plugin = klass.new(@ohai, "/tmp/plugins/thing.rb")
+      end
+
+      it "should raise a NoAttributeError" do
+        expect { @runner.run_plugin(@plugin) }.to raise_error(Ohai::NoAttributeError)
+      end
+
+      it "should not run the plugin" do
+        expect { @runner.run_plugin(@plugin) }.to raise_error(Ohai::NoAttributeError)
+        @plugin.has_run?.should be_false
+      end
+    end
+
+    describe "when the dependency has a single provider" do
+      before(:each) do
+        klass1 = Ohai.plugin { provides("thing"); collect_data { thing("thang") } }
+        klass2 = Ohai.plugin { provides("other"); depends("thing"); collect_data { other(thing) } }
+
+        @plugins = []
+        [klass1, klass2].each do |klass|
+          @plugins << klass.new(@ohai, "/tmp/plugins/source_dont_matter.rb")
+        end
+        @plugin1, @plugin2 = @plugins
+      end
+
+      it "should locate the provider" do
+        @ohai.attributes[:thing] = Mash.new
+        @ohai.attributes[:thing][:providers] = [@plugin1]
+        @ohai.attributes[:other] = Mash.new
+        @ohai.attributes[:other][:providers] = [@plugin2]
+
+        @runner.should_receive(:fetch_providers).twice.with(["thing"]).and_return([@plugin1])
+        @runner.should_receive(:fetch_providers).with([]).and_return([])
+        @runner.run_plugin(@plugin2)
+      end
+
+      it "should run the plugins" do
+        @runner.stub(:fetch_providers).with(["thing"]).and_return([@plugin1])
+        @runner.stub(:fetch_providers).with([]).and_return([])
+
+        @runner.run_plugin(@plugin2)
+        @plugins.each do |plugin|
+          plugin.has_run?.should be_true
+        end
+      end
+    end
+
+    describe "when the dependency has multiple providers" do
+      before(:each) do
+        klass1 = Ohai.plugin { provides("thing"); collect_data { thing(Mash.new) } }
+        klass2 = Ohai.plugin { provides("other"); depends("thing"); collect_data { other(thing) } }
+
+        @plugins = []
+        [klass1, klass1, klass2].each do |klass|
+          @plugins << klass.new(@ohai, "/tmp/plugins/whateva.rb")
+        end
+        @plugin1, @plugin2, @plugin3 = @plugins
+      end
+
+      it "should locate each provider" do
+        @ohai.attributes[:thing] = Mash.new
+        @ohai.attributes[:thing][:providers] = [@plugin1, @plugin2]
+        @ohai.attributes[:other] = Mash.new
+        @ohai.attributes[:other][:providers] = [@plugin3]
+
+        @runner.should_receive(:fetch_providers).twice.with(["thing"]).and_return([@plugin1, @plugin2])
+        @runner.should_receive(:fetch_providers).twice.with([]).and_return([])
+        @runner.run_plugin(@plugin3)
+      end
+
+      it "should run the plugins" do
+        @runner.stub(:fetch_providers).with([]).and_return([])
+        @runner.stub(:fetch_providers).with(["thing"]).and_return([@plugin1, @plugin2])
+        @runner.run_plugin(@plugin3)
+        @plugins.each do |plugin|
+          plugin.has_run?.should be_true
+        end
+      end
+    end
+  end
+  
+  describe "when running a plugin with many dependencies" do
+    before(:each) do
+      @ohai = Ohai::System.new
+      @runner = Ohai::Runner.new(@ohai, true)
+
+      klass1 = Ohai.plugin { provides("one"); collect_data { one(1) } }
+      klass2 = Ohai.plugin { provides("two"); collect_data { two(2) } }
+      klass3 = Ohai.plugin { provides("three"); depends("one", "two"); collect_data { three(3) } }
+
+      @plugins = []
+      [klass1, klass2, klass3].each do |klass|
+        @plugins << klass.new(@ohai, "/tmp/plugins/number.rb")
+      end
+      @plugin1, @plugin2, @plugin3 = @plugins
+    end
+
+    it "should locate each provider" do
+      @ohai.attributes[:one] = Mash.new
+      @ohai.attributes[:one][:providers] = [@plugin1]
+      @ohai.attributes[:two] = Mash.new
+      @ohai.attributes[:two][:providers] = [@plugin2]
+      @ohai.attributes[:three] = Mash.new
+      @ohai.attributes[:three][:providers] = [@plugin3]
+
+      @runner.should_receive(:fetch_providers).twice.with([]).and_return([])
+      @runner.should_receive(:fetch_providers).twice.with(["one", "two"]).and_return([@plugin1, @plugin2])
+      @runner.run_plugin(@plugin3)
+    end
+
+    it "should run the plugins" do
+      @runner.stub(:fetch_providers).with([]).and_return([])
+      @runner.stub(:fetch_providers).with(["one", "two"]).and_return([@plugin1, @plugin2])
+      @runner.run_plugin(@plugin3)
+      @plugins.each do |plugin|
+        plugin.has_run?.should be_true
+      end
+    end
+  end
+
+  describe "when a cycle is detected" do
+    before(:each) do
+      @ohai = Ohai::System.new
+      @runner = Ohai::Runner.new(@ohai, true)
+
+      klass1 = Ohai.plugin { provides("thing"); depends("other"); collect_data { thing(other) } }
+      klass2 = Ohai.plugin { provides("other"); depends("thing"); collect_data { other(thing) } }
+
+      @plugins = []
+      [klass1, klass2].each_with_index do |klass, idx|
+        @plugins << klass.new(@ohai, "/tmp/plugins/plugin#{idx}.rb")
+      end
+      @plugin1, @plugin2 = @plugins
+    end
+
+    it "should raise a DependencyCycleError" do
+      @runner.stub(:fetch_providers).with(["thing"]).and_return([@plugin1])
+      @runner.stub(:fetch_providers).with(["other"]).and_return([@plugin2])
+      expect { @runner.run_plugin(@plugin1) }.to raise_error(Ohai::DependencyCycleError)
+    end
+  end
+end
+
+describe Ohai::Runner, "fetch_providers" do
+  before(:each) do
+    @ohai = Ohai::System.new
+    @runner = Ohai::Runner.new(@ohai, true)
+  end
+
+  describe "for a single attribute" do
+    describe "with one provider" do
+      it "should return the provider" do
+        plugin = Ohai::DSL::Plugin.new(@ohai, "")
+        @ohai.attributes[:single] = Mash.new
+        @ohai.attributes[:single][:providers] = [plugin]
+
+        dependency_providers = @runner.fetch_providers(["single"])
+        dependency_providers.should eql([plugin])
+      end
+    end
+
+    describe "with multiple providers" do
+      it "should return all providers" do
+        plugin1 = Ohai::DSL::Plugin.new(@ohai, "")
+        plugin2 = Ohai::DSL::Plugin.new(@ohai, "")
+        @ohai.attributes[:single] = Mash.new
+        @ohai.attributes[:single][:providers] = [plugin1, plugin2]
+
+        dependency_providers = @runner.fetch_providers(["single"])
+        dependency_providers.should eql([plugin1, plugin2])
+      end
+    end
+  end
+
+  describe "for multiple attributes" do
+    describe "with unique providers" do
+      it "should return each provider" do
+        plugin1 = Ohai::DSL::Plugin.new(@ohai, "")
+        plugin2 = Ohai::DSL::Plugin.new(@ohai, "")
+        @ohai.attributes[:one] = Mash.new
+        @ohai.attributes[:one][:providers] = [plugin1]
+        @ohai.attributes[:two] = Mash.new
+        @ohai.attributes[:two][:providers] = [plugin2]
+
+        dependency_providers = @runner.fetch_providers(["one", "two"])
+        dependency_providers.should eql([plugin1, plugin2])
+      end
+    end
+
+    describe "with shared providers" do
+      it "should return unique providers" do
+        plugin = Ohai::DSL::Plugin.new(@ohai, "")
+        @ohai.attributes[:one] = Mash.new
+        @ohai.attributes[:one][:providers] = [plugin]
+        @ohai.attributes[:two] = Mash.new
+        @ohai.attributes[:two][:providers] = [plugin]
+
+        dependency_providers = @runner.fetch_providers(["one", "two"])
+        dependency_providers.should eql([plugin])
+      end
+    end
+  end
+
+  describe "for multi-level attributes" do
+    it "should collect the provider" do
+      plugin = Ohai::DSL::Plugin.new(@ohai, "")
+      @ohai.attributes[:top] = Mash.new
+      @ohai.attributes[:top][:middle] = Mash.new
+      @ohai.attributes[:top][:middle][:bottom] = Mash.new
+      @ohai.attributes[:top][:middle][:bottom][:providers] = [plugin]
+
+      dependency_providers = @runner.fetch_providers(["top/middle/bottom"])
+      dependency_providers.should eql([plugin])
+    end
+  end
+end
+
+