Only wrap request processing with our USR1 signal handler so FastCGI can trap...

Only wrap request processing with our USR1 signal handler so FastCGI can trap it and raise an exception while waiting for connections. Idle processes exit immediately rather than waiting for another request; active processes gracefully exit when the request is finished.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@5485 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

railties/CHANGELOG

 *SVN*
 
+* Only wrap request processing with our USR1 signal handler so FastCGI can trap it and raise an exception while waiting for connections. Idle processes exit immediately rather than waiting for another request; active processes gracefully exit when the request is finished.  [Jeremy Kemper]
+
 * Alter prior change to use require_dependency instead of require_or_load. Causes ApplicationController to be reloaded again. Closes #6587. [Nicholas Seckar]
 
 * Rake: use absolute paths to load lib and vendor tasks so they may be run outside of RAILS_ROOT.  #6584 [jchris]

railties/lib/fcgi_handler.rb

@@ -6,11 +6,13 @@
 class RailsFCGIHandler
   SIGNALS = {
     'HUP'     => :reload,
+    'INT'     => :exit_now,
     'TERM'    => :exit_now,
     'USR1'    => :exit,
     'USR2'    => :restart,
     'SIGTRAP' => :breakpoint
   }
+  GLOBAL_SIGNALS = SIGNALS.keys - %w(USR1)
 
   attr_reader :when_ready
 
@@ -92,17 +94,23 @@ def dispatcher_error(e, msg = "")
     end
 
     def install_signal_handlers
-      SIGNALS.each do |signal, handler_name|
-        install_signal_handler(signal, method("#{handler_name}_handler").to_proc)
-      end
+      GLOBAL_SIGNALS.each { |signal| install_signal_handler(signal) }
     end
 
-    def install_signal_handler(signal, handler)
+    def install_signal_handler(signal, handler = nil)
+      handler ||= method("#{SIGNALS[signal]}_handler").to_proc
       trap(signal, handler)
     rescue ArgumentError
       dispatcher_log :warn, "Ignoring unsupported signal #{signal}."
     end
 
+    def with_signal_handler(signal)
+      install_signal_handler(signal)
+      yield
+    ensure
+      install_signal_handler(signal, 'DEFAULT')
+    end
+
     def exit_now_handler(signal)
       dispatcher_log :info, "asked to terminate immediately"
       exit
@@ -127,10 +135,13 @@ def breakpoint_handler(signal)
       dispatcher_log :info, "asked to breakpoint ASAP"
       @when_ready = :breakpoint
     end
-    
+
     def process_each_request!(provider)
-      provider.each_cgi do |cgi| 
-        process_request(cgi)
+      cgi = nil
+      provider.each_cgi do |cgi|
+        with_signal_handler 'USR1' do
+          process_request(cgi)
+        end
 
         case when_ready
           when :reload
@@ -148,6 +159,9 @@ def process_each_request!(provider)
 
         gc_countdown
       end
+    rescue SignalException => signal
+      raise unless signal.message == 'SIGUSR1'
+      close_connection(cgi) if cgi
     end
 
     def process_request(cgi)
@@ -161,7 +175,7 @@ def restart!
       config       = ::Config::CONFIG
       ruby         = File::join(config['bindir'], config['ruby_install_name']) + config['EXEEXT']
       command_line = [ruby, $0, ARGV].flatten.join(' ')
-      
+
       dispatcher_log :info, "restarted"
 
       exec(command_line)
@@ -183,7 +197,7 @@ def restore!
       Dispatcher.reset_application!
       ActionController::Routing::Routes.reload
     end
-    
+
     def breakpoint!
       require 'breakpoint'
       port = defined?(BREAKPOINT_SERVER_PORT) ? BREAKPOINT_SERVER_PORT : 42531
@@ -197,14 +211,14 @@ def run_gc!
       @gc_request_countdown = gc_request_period
       GC.enable; GC.start; GC.disable
     end
-    
+
     def gc_countdown
       if gc_request_period
         @gc_request_countdown -= 1
         run_gc! if @gc_request_countdown <= 0
       end
     end
-    
+
     def close_connection(cgi)
       cgi.instance_variable_get("@request").finish
     end