Adding support for running metrics against a particular git hash

Gemfile

@@ -6,6 +6,8 @@ group :test, :local_development  do
   gem 'pry-nav'
   # https://github.com/kina/simplecov-rcov-text
   gem 'simplecov-rcov-text', group: :metrics
+  # Some tests require git gem to test the Git integration
+  gem 'git'
 end
 
 gemspec :path => File.expand_path('..', __FILE__)

lib/metric_fu/cli/parser.rb

@@ -49,6 +49,7 @@ def configure_options(p)
 
           add_format_option(p)
           add_output_option(p)
+          add_git_option(p)
 
           p.banner = @banner unless @banner.nil?
           p.on_tail("-h", "--help", "Show this message") {puts p ; success!}
@@ -76,6 +77,14 @@ def add_general_option(p, o)
           end
         end
 
+        def add_git_option(p)
+          p.on('--githash COMMIT_HASH',
+              'Specify the git hash to run metric_fu against') do |o|
+            @result[:githash] ||= ''
+            @result[:githash] << o
+          end
+        end
+
         def add_output_option(p)
           p.on("--out FILE|DIR",
               "Specify the file or directory to use for output",

lib/metric_fu/configuration.rb

@@ -122,8 +122,8 @@ def metric_manually_configured?(metric)
     end
 
     # TODO: Reconsider method name/behavior, as it really adds a formatter
-    def configure_formatter(format, output = nil)
-      @formatters << MetricFu::Formatter.class_for(format).new(output: output)
+    def configure_formatter(format, output = nil, filename = nil)
+      @formatters << MetricFu::Formatter.class_for(format).new(output: output, filename: filename)
     end
 
     # @return [Array<Symbol>] names of enabled metrics with graphs

lib/metric_fu/formatter/html.rb

@@ -17,7 +17,7 @@ def finish
         mf_debug "** SAVING REPORT DATA OUTPUT TO #{MetricFu::Io::FileSystem.directory('data_directory')}"
         # TODO: Allow customizing output filenames
         MetricFu::Formatter::YAML.new(
-          output: MetricFu.run_path.join("#{MetricFu::Io::FileSystem.directory('data_directory')}/#{Time.now.strftime("%Y%m%d")}.yml")
+          output: output_yml
         ).finish
 
         mf_debug "** SAVING TEMPLATIZED REPORT"
@@ -42,6 +42,12 @@ def output_directory
         @output ||= dir_for(@options[:output]) || MetricFu.run_path.join(MetricFu::Io::FileSystem.directory('output_directory'))
       end
 
+      def output_yml
+        filename_prefix = @options[:filename] || Time.now.strftime("%Y%m%d")
+
+        MetricFu.run_path.join("#{MetricFu::Io::FileSystem.directory('data_directory')}/#{filename_prefix}.yml")
+      end
+
       # Instantiates a new template class based on the configuration set
       # in MetricFu::Configuration, or through the MetricFu.config block
       # in your rake file (defaults to the included AwesomeTemplate),

lib/metric_fu/metrics/graph.rb

@@ -48,7 +48,11 @@ def generate_graphs_for_file(metric_file)
       date_parts = year_month_day_from_filename(metric_file)
       metrics = MetricFu::Utility.load_yaml(metric_file)
 
-      build_graph(metrics, "#{date_parts[:m]}/#{date_parts[:d]}")
+      # Determine the name of the graph files based on the original metric_file name
+      graph_filename = metric_file
+      graph_filename = "#{date_parts[:m]}/#{date_parts[:d]}" if date_parts
+
+      build_graph(metrics, graph_filename)
     rescue NameError => e
       mf_log "#{e.message} called in MetricFu::Graph.generate with #{metric_file}"
     end
@@ -66,7 +70,9 @@ def graph!
     end
 
     def year_month_day_from_filename(path_to_file_with_date)
-      date = path_to_file_with_date.match(/\/(\d+).yml$/)[1]
+      date = path_to_file_with_date.match(/\/(\d+).yml$/)
+      return nil unless date
+      date = date[1]
       {:y => date[0..3].to_i, :m => date[4..5].to_i, :d => date[6..7].to_i}
     end
   end

lib/metric_fu/run.rb

@@ -7,6 +7,7 @@ def initialize
     def run(options={})
       configure_run(options)
       measure
+      reset_git(options) if git_configured? options
       display_results if options[:open]
     end
 
@@ -28,6 +29,7 @@ def display_results
     private
     def configure_run(options)
       disable_metrics(options)
+      configure_git(options)
       configure_formatters(options)
     end
     def disable_metrics(options)
@@ -55,20 +57,64 @@ def configure_metric(metric, metric_options)
       end
     end
     def configure_formatters(options)
+      filename = options[:githash] # Set the filename for the output; nil is a valid value
+
       # Configure from command line if any.
       if options[:format]
         MetricFu.configuration.formatters.clear # Command-line format takes precedence.
         Array(options[:format]).each do |format, o|
-          MetricFu.configuration.configure_formatter(format, o)
+          MetricFu.configuration.configure_formatter(format, o, filename)
         end
       end
       # If no formatters specified, use defaults.
       if MetricFu.configuration.formatters.empty?
         Array(MetricFu::Formatter::DEFAULT).each do |format, o|
-          MetricFu.configuration.configure_formatter(format, o)
+          MetricFu.configuration.configure_formatter(format, o, filename)
         end
       end
     end
+    def configure_git(options)
+      return unless git_configured? options
+
+      execute_with_git do
+        begin
+          @git ||= Git.init
+          @orig_branch ||= @git.current_branch
+
+          mf_log "CHECKING OUT '#{options[:githash]}'"
+          @git.checkout(options[:githash])
+        rescue Git::GitExecuteError => e
+          mf_log "Unable to checkout githash: #{options[:githash]}"
+          raise "Unable to checkout githash: #{options[:githash]}: #{e}"
+        end
+      end
+    end
+    def reset_git(options)
+      return unless git_configured? options
+
+      execute_with_git do
+        begin
+          @git ||= Git.init
+          mf_log "CHECKING OUT ORIGINAL BRANCH '#{@orig_branch}'"
+          @git.checkout(@orig_branch)
+        rescue Git::GitExecuteError => e
+          mf_log "Unable to reset git status to branch '#{@orig_branch}'"
+          raise "Unable to reset git status to branch '#{@orig_branch}'"
+        end
+      end
+    end
+    def execute_with_git(&block)
+      begin
+        require 'git'
+        yield
+      rescue LoadError => e
+        mf_log 'Cannot select git hash; please install git gem'
+        raise 'Cannot select git hash; please install git gem'
+      end
+    end
+    def git_configured?(options)
+      options.size > 0 && options.has_key?(:githash)
+    end
     def reporter
       MetricFu::Reporter.new(MetricFu.configuration.formatters)
     end

spec/cli/helper_spec.rb

@@ -167,6 +167,12 @@
       end
     end
 
+    context 'given a single git hash/tag' do
+      it 'sets the git flag' do
+        helper.process_options(['--githash', 'testhash'])[:githash].should eq 'testhash'
+      end
+    end
+
   end
 
 end

spec/metric_fu/formatter/html_spec.rb

@@ -49,6 +49,13 @@ def directory(name)
       }.to create_file("#{directory('data_directory')}/#{Time.now.strftime("%Y%m%d")}.yml")
     end
 
+    it 'creates a data yaml file based on specified filename' do
+      fn = 'testfilename'
+      expect {
+        MetricFu::Formatter::HTML.new(filename: fn).finish
+      }.to create_file("#{directory('data_directory')}/#{fn}.yml")
+    end
+
     it "creates a report index html file" do
       expect {
       MetricFu::Formatter::HTML.new.finish

spec/metric_fu/run_spec.rb

@@ -60,6 +60,31 @@ def data_directory
       expect { metric_fu }.to create_file("#{output_directory}/index.html")
     end
 
+    context 'with a git-hash specified' do
+      let(:githash) { 'testhash' }
+
+      before do
+        @branch = 'original_branch'
+
+        # Stub out the git checkout method to not actually checkout a branch, but keep track of the state
+        Git::Base.any_instance.stub(:checkout) do |branch|
+          @branch = branch
+        end
+
+        Git::Base.any_instance.stub(:current_branch) { @branch }
+      end
+
+      it "creates a git-hash yaml file" do
+        expect { metric_fu "--githash #{githash} --no-open" }.to create_file("#{data_directory}/#{githash}.yml")
+      end
+
+      it 'resets context back to the original git state' do
+        metric_fu "--githash #{githash} --no-open"
+
+        expect(@branch).to eq 'original_branch'
+      end
+    end
+
     context "with configured formatter" do
       it "outputs using configured formatter" do
         expect {

spec/spec_helper.rb

@@ -19,6 +19,7 @@
 require 'construct'
 require 'json'
 require 'pry-nav'
+require 'git'
 
 # add lib to the load path just like rubygems does
 $:.unshift File.expand_path("../../lib", __FILE__)