LogTailer should be invoked after all logs in threads were flushed.

1 files changed, 12 insertions, 2 deletions

diff --git a/railties/lib/rails/subscriber.rb b/railties/lib/rails/subscriber.rb
index 88a6f77eaa..2c62f178b8 100644
--- a/railties/lib/rails/subscriber.rb
+++ b/railties/lib/rails/subscriber.rb
@@ -33,8 +33,9 @@ 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
-    cattr_accessor :colorize_logging, :instance_writer => false
+    mattr_accessor :colorize_logging, :tail_log
     self.colorize_logging = true
+    self.tail_log = false
 
     # Embed in a String to clear all previous ANSI sequences.
     CLEAR      = "\e[0m"
@@ -58,6 +59,12 @@ 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]
@@ -66,7 +73,10 @@ module Rails
         subscriber.send(name, ActiveSupport::Notifications::Event.new(*args))
       end
 
-      flush_all! if args[0] == "action_dispatch.callback"
+      if args[0] == "action_dispatch.callback" && !subscribers.empty?
+        flush_all!
+        log_tailer.tail! if tail_log
+      end
     end
 
     # Flush all subscribers' logger.