Profile various stages of a site's build process (#6760)

Merge pull request 6760

.rubocop.yml

@@ -139,6 +139,7 @@ Style/FormatStringToken:
   Exclude:
     - lib/jekyll/utils/ansi.rb
     - lib/jekyll/liquid_renderer/table.rb
+    - lib/jekyll/profiler.rb
 Style/FrozenStringLiteralComment:
   EnforcedStyle: always
 Style/GuardClause:

lib/jekyll.rb

@@ -69,6 +69,7 @@ module Jekyll
   autoload :PathManager,         "jekyll/path_manager"
   autoload :PluginManager,       "jekyll/plugin_manager"
   autoload :Publisher,           "jekyll/publisher"
+  autoload :Profiler,            "jekyll/profiler"
   autoload :Reader,              "jekyll/reader"
   autoload :Regenerator,         "jekyll/regenerator"
   autoload :RelatedPosts,        "jekyll/related_posts"

lib/jekyll/liquid_renderer/table.rb

@@ -10,31 +10,11 @@ def initialize(stats)
       end
 
       def to_s(num_of_rows = 50)
-        tabulate(data_for_table(num_of_rows))
+        Jekyll::Profiler.tabulate(data_for_table(num_of_rows))
       end
 
       private
 
-      def tabulate(data)
-        require "terminal-table"
-
-        header = data.shift
-        footer = data.pop
-        output = +"\n"
-
-        table = Terminal::Table.new do |t|
-          t << header
-          t << :separator
-          data.each { |row| t << row }
-          t << :separator
-          t << footer
-          t.style = { :alignment => :right, :border_top => false, :border_bottom => false }
-          t.align_column(0, :left)
-        end
-
-        output << table.to_s << "\n"
-      end
-
       # rubocop:disable Metrics/AbcSize
       def data_for_table(num_of_rows)
         sorted = @stats.sort_by { |_, file_stats| -file_stats[:time] }

lib/jekyll/profiler.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+module Jekyll
+  class Profiler
+    TERMINAL_TABLE_STYLES = {
+      :alignment     => :right,
+      :border_top    => false,
+      :border_bottom => false,
+    }.freeze
+    private_constant :TERMINAL_TABLE_STYLES
+
+    def self.tabulate(table_rows)
+      require "terminal-table"
+
+      rows   = table_rows.dup
+      header = rows.shift
+      footer = rows.pop
+      output = +"\n"
+
+      table = Terminal::Table.new do |t|
+        t << header
+        t << :separator
+        rows.each { |row| t << row }
+        t << :separator
+        t << footer
+        t.style = TERMINAL_TABLE_STYLES
+        t.align_column(0, :left)
+      end
+
+      output << table.to_s << "\n"
+    end
+
+    def initialize(site)
+      @site = site
+    end
+
+    def profile_process
+      profile_data = { "PHASE" => "TIME" }
+      total_time = 0
+
+      [:reset, :read, :generate, :render, :cleanup, :write].each do |method|
+        start_time = Time.now
+        @site.send(method)
+        end_time = (Time.now - start_time).round(4)
+        profile_data[method.to_s.upcase] = format("%.4f", end_time)
+        total_time += end_time
+      end
+
+      profile_data["TOTAL TIME"] = format("%.4f", total_time)
+
+      Jekyll.logger.info "\nBuild Process Summary:"
+      Jekyll.logger.info Profiler.tabulate(Array(profile_data))
+
+      Jekyll.logger.info "\nSite Render Stats:"
+      @site.print_stats
+    end
+  end
+end

lib/jekyll/site.rb

@@ -10,7 +10,7 @@ class Site
                   :gems, :plugin_manager, :theme
 
     attr_accessor :converters, :generators, :reader
-    attr_reader   :regenerator, :liquid_renderer, :includes_load_paths, :filter_cache
+    attr_reader   :regenerator, :liquid_renderer, :includes_load_paths, :filter_cache, :profiler
 
     # Public: Initialize a new Site.
     #
@@ -26,6 +26,7 @@ def initialize(config)
       @filter_cache    = {}
 
       @reader          = Reader.new(self)
+      @profiler        = Profiler.new(self)
       @regenerator     = Regenerator.new(self)
       @liquid_renderer = LiquidRenderer.new(self)
 
@@ -71,13 +72,14 @@ def config=(config)
     #
     # Returns nothing.
     def process
+      return profiler.profile_process if config["profile"]
+
       reset
       read
       generate
       render
       cleanup
       write
-      print_stats if config["profile"]
     end
 
     def print_stats