2 files changed, 9 insertions, 4 deletions
diff --git a/railties/lib/rails/rack/log_tailer.rb b/railties/lib/rails/rack/log_tailer.rb
index 18f22e8089..bc26421a9e 100644
--- a/railties/lib/rails/rack/log_tailer.rb
+++ b/railties/lib/rails/rack/log_tailer.rb
@@ -1,13 +1,17 @@
+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.exists?(path)
+        if ::File.exist?(path)
           @cursor = ::File.size(path)
           @file = ::File.open(path, 'r')
         end
diff --git a/railties/lib/rails/rack/logger.rb b/railties/lib/rails/rack/logger.rb
index ef4cdcb080..3b35798679 100644
--- a/railties/lib/rails/rack/logger.rb
+++ b/railties/lib/rails/rack/logger.rb
@@ -11,7 +11,6 @@ module Rails
       def initialize(app, taggers = nil)
         @app          = app
         @taggers      = taggers || []
-        @instrumenter = ActiveSupport::Notifications.instrumenter
       end
 
       def call(env)
@@ -33,7 +32,8 @@ module Rails
           logger.debug ''
         end
 
-        @instrumenter.start 'request.action_dispatch', request: request
+        instrumenter = ActiveSupport::Notifications.instrumenter
+        instrumenter.start 'request.action_dispatch', request: request
         logger.info started_request_message(request)
         resp = @app.call(env)
         resp[2] = ::Rack::BodyProxy.new(resp[2]) { finish(request) }
@@ -70,7 +70,8 @@ module Rails
       private
 
       def finish(request)
-        @instrumenter.finish 'request.action_dispatch', request: request
+        instrumenter = ActiveSupport::Notifications.instrumenter
+        instrumenter.finish 'request.action_dispatch', request: request
       end
 
       def development?