Fix an issue where log was not being tailed in the first request.

railties/lib/rails/commands/server.rb

@@ -46,7 +46,7 @@ module Rails
       trap(:INT) { exit }
       puts "=> Ctrl-C to shutdown server" unless options[:daemonize]
 
-      Rails::Subscriber.tail_log = true unless options[:daemonize]
+      initialize_log_tailer! unless options[:daemonize]
       super
     ensure
       puts 'Exiting' unless options[:daemonize]
@@ -58,6 +58,10 @@ module Rails
       Hash.new(middlewares)
     end
 
+    def log_path
+      "log/#{options[:environment]}.log"
+    end
+
     def default_options
       super.merge({
         :Port        => 3000,
@@ -67,5 +71,14 @@ module Rails
         :pid         => "tmp/pids/server.pid"
       })
     end
+
+  protected
+
+    # LogTailer should not be used as a middleware since the logging happens
+    # async in a request and the middleware calls are sync. So we send it
+    # to subscriber which will be responsible for calling tail! in the log tailer.
+    def initialize_log_tailer!
+      Rails::Subscriber.log_tailer = Rails::Rack::LogTailer.new(nil, log_path)
+    end
   end
 end

railties/lib/rails/subscriber.rb

@@ -33,9 +33,8 @@ module Rails
   # Subscriber also has some helpers to deal with logging and automatically flushes
   # all logs when the request finishes (via action_dispatch.callback notification).
   class Subscriber
-    mattr_accessor :colorize_logging, :tail_log
+    mattr_accessor :colorize_logging, :log_tailer
     self.colorize_logging = true
-    self.tail_log = false
 
     # Embed in a String to clear all previous ANSI sequences.
     CLEAR      = "\e[0m"
@@ -59,12 +58,6 @@ module Rails
       @subscribers ||= {}
     end
 
-    # Use Rails::Rack::LogTailer to do the log tailing.
-    # TODO Leave this as middleware or move inside Subscriber?
-    def self.log_tailer
-      @log_tailer ||= Rails::Rack::LogTailer.new(nil, "log/#{Rails.env}.log")
-    end
-
     def self.dispatch(args)
       namespace, name = args[0].split(".")
       subscriber = subscribers[namespace.to_sym]
@@ -75,7 +68,7 @@ module Rails
 
       if args[0] == "action_dispatch.callback" && !subscribers.empty?
         flush_all!
-        log_tailer.tail! if tail_log
+        log_tailer.tail! if log_tailer
       end
     end
 

railties/test/subscriber_test.rb

@@ -108,14 +108,13 @@ module SubscriberTest
   def test_tails_logs_when_action_dispatch_callback_is_received
     log_tailer = mock()
     log_tailer.expects(:tail!)
-    Rails::Rack::LogTailer.expects(:new).with(nil, "log/development.log").returns(log_tailer)
+    Rails::Subscriber.log_tailer = log_tailer
 
-    Rails::Subscriber.tail_log = true
     Rails::Subscriber.add :my_subscriber, @subscriber
     instrument "action_dispatch.callback"
     wait
   ensure
-    Rails::Subscriber.tail_log = false
+    Rails::Subscriber.log_tailer = nil
   end
 
   class SyncSubscriberTest < ActiveSupport::TestCase