1 files changed, 38 insertions, 0 deletions
diff --git a/railties/lib/rails/rack/log_tailer.rb b/railties/lib/rails/rack/log_tailer.rb
new file mode 100644
index 0000000000..bc26421a9e
--- /dev/null
+++ b/railties/lib/rails/rack/log_tailer.rb
@@ -0,0 +1,38 @@
+require 'active_support/deprecation'
+
+module Rails
+  module Rack
+    class LogTailer
+      def initialize(app, log = nil)
+        ActiveSupport::Deprecation.warn "LogTailer is deprecated and will be removed on Rails 5"
+
+        @app = app
+
+        path = Pathname.new(log || "#{::File.expand_path(Rails.root)}/log/#{Rails.env}.log").cleanpath
+
+        @cursor = @file = nil
+        if ::File.exist?(path)
+          @cursor = ::File.size(path)
+          @file = ::File.open(path, 'r')
+        end
+      end
+
+      def call(env)
+        response = @app.call(env)
+        tail!
+        response
+      end
+
+      def tail!
+        return unless @cursor
+        @file.seek @cursor
+
+        unless @file.eof?
+          contents = @file.read
+          @cursor = @file.tell
+          $stdout.print contents
+        end
+      end
+    end
+  end
+end