From 5650bc90940bd850a2f44bd3b58549d6b336dcd0 Mon Sep 17 00:00:00 2001
From: Jeremy Kemper <jeremy@bitsweat.net>
Date: Sat, 2 Jul 2005 04:52:14 +0000
Subject:  r1588@asus:  jeremy | 2005-07-02 03:14:45 -0700  Optional periodic
 garbage collection for dispatch.fcgi.  Graceful exit on TERM also (a la
 Apache1).  Ignore signals the platform does not support, such as USR1 on
 Windows.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1592 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
---
 railties/lib/fcgi_handler.rb | 79 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 66 insertions(+), 13 deletions(-)

(limited to 'railties/lib')

diff --git a/railties/lib/fcgi_handler.rb b/railties/lib/fcgi_handler.rb
index f615ff6d34..f489627985 100644
--- a/railties/lib/fcgi_handler.rb
+++ b/railties/lib/fcgi_handler.rb
@@ -3,41 +3,77 @@ require 'logger'
 require 'dispatcher'
 
 class RailsFCGIHandler
+  SIGNALS = {
+    'HUP'  => :reload,
+    'TERM' => :graceful_exit,
+    'USR1' => :graceful_exit
+  }
+
   attr_reader :when_ready
   attr_reader :processing
 
-  def self.process!
-    new.process!
+  attr_accessor :log_file_path
+  attr_accessor :gc_request_period
+
+
+  # Initialize and run the FastCGI instance, passing arguments through to new.
+  def self.process!(*args, &block)
+    new(*args, &block).process!
   end
 
-  def initialize(log_file_path = "#{RAILS_ROOT}/log/fastcgi.crash.log")
+  # Initialize the FastCGI instance with the path to a crash log
+  # detailing unhandled exceptions (default RAILS_ROOT/log/fastcgi.crash.log)
+  # and the number of requests to process between garbage collection runs
+  # (default nil for normal GC behavior.)  Optionally, pass a block which
+  # takes this instance as an argument for further configuration.
+  def initialize(log_file_path = nil, gc_request_period = nil)
     @when_ready = nil
     @processing = false
 
-    trap("HUP",  method(:restart_handler).to_proc)
-    trap("USR1", method(:trap_handler).to_proc)
+    self.log_file_path = log_file_path || "#{RAILS_ROOT}/log/fastcgi.crash.log"
+    self.gc_request_period = gc_request_period
+
+    # Yield for additional configuration.
+    yield self if block_given?
 
-    # initialize to 11 seconds ago to minimize special cases
+    # Safely install signal handlers.
+    install_signal_handlers
+
+    # Start error timestamp at 11 seconds ago.
     @last_error_on = Time.now - 11
 
-    @log_file_path = log_file_path
     dispatcher_log(:info, "starting")
   end
 
   def process!
+    # Make a note of $" so we can safely reload this instance.
     mark!
 
+    # Begin countdown to garbage collection.
+    run_gc! if gc_request_period
+
     FCGI.each_cgi do |cgi| 
-      if when_ready == :restart
+      # Safely reload this instance if requested.
+      if when_ready == :reload
+        run_gc! if gc_request_period
         restore!
         @when_ready = nil
-        dispatcher_log(:info, "restarted")
+        dispatcher_log(:info, "reloaded")
       end
 
       process_request(cgi)
+
+      # Break if graceful exit requested.
       break if when_ready == :exit
+
+      # Garbage collection countdown.
+      if gc_request_period
+        @gc_request_countdown -= 1
+        run_gc! if @gc_request_countdown <= 0
+      end
     end
 
+    GC.enable
     dispatcher_log(:info, "terminated gracefully")
 
   rescue SystemExit => exit_error
@@ -75,7 +111,19 @@ class RailsFCGIHandler
       dispatcher_log(:error, error_message)
     end
 
-    def trap_handler(signal)
+    def install_signal_handlers
+      SIGNALS.each do |signal, handler_name|
+        install_signal_handler signal, method("#{handler_name}_handler").to_proc
+      end
+    end
+
+    def install_signal_handler(signal, handler)
+      trap signal, handler
+    rescue ArgumentError
+      dispatcher_log :warn, "Ignoring unsupported signal #{signal}."
+    end
+
+    def graceful_exit_handler(signal)
       if processing
         dispatcher_log :info, "asked to terminate ASAP"
         @when_ready = :exit
@@ -85,9 +133,9 @@ class RailsFCGIHandler
       end
     end
 
-    def restart_handler(signal)
-      @when_ready = :restart
-      dispatcher_log :info, "asked to restart ASAP"
+    def reload_handler(signal)
+      @when_ready = :reload
+      dispatcher_log :info, "asked to reload ASAP"
     end
 
     def process_request(cgi)
@@ -109,4 +157,9 @@ class RailsFCGIHandler
       Dispatcher.reset_application!
       ActionController::Routing::Routes.reload
     end
+
+    def run_gc!
+      @gc_request_countdown = gc_request_period
+      GC.enable; GC.start; GC.disable
+    end
 end
-- 
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