add unicorn launcher to support live reloads

add oobgc rudimentary support

config/initializers/99-rack-cache.rb

@@ -6,7 +6,7 @@ enabled = if Rails.configuration.respond_to?(:enable_anon_caching)
             Rails.env.production?
           end
 
-if enabled
+if !ENV['DISCOURSE_DISABLE_ANON_CACHE'] && enabled
   Rails.configuration.middleware.insert 0, Middleware::AnonymousCache
 end
 

config/initializers/99-unicorn.rb

@@ -0,0 +1,4 @@
+if (oobgc=ENV['UNICORN_OOBGC_REQS'].to_i) > 0
+   require 'unicorn/oob_gc'
+   Rails.configuration.middleware.insert 0, Unicorn::OobGC, oobgc
+end

config/unicorn.conf.rb

@@ -1,5 +1,8 @@
 # See http://unicorn.bogomips.org/Unicorn/Configurator.html
 
+# RUN out of band GC every 2 requests
+# ENV['UNICORN_OOBGC_REQS'] = "2" unless ENV['UNICORN_OOBGC_REQS']
+
 discourse_path = File.expand_path(File.expand_path(File.dirname(__FILE__)) + "/../")
 
 # tune down if not enough ram
@@ -39,8 +42,30 @@ before_fork do |server, worker|
   unless initialized
     # load up the yaml for the localization bits, in master process
     I18n.t(:posts)
+
+    # load up all models and schema
+    (ActiveRecord::Base.connection.tables - %w[schema_migrations]).each do |table|
+      table.classify.constantize.first rescue nil
+    end
+
     # get rid of rubbish so we don't share it
     GC.start
+
+    initialized = true
+
+    supervisor = ENV['UNICORN_SUPERVISOR_PID'].to_i
+    if supervisor > 0
+      Thread.new do
+        while true
+          unless File.exists?("/proc/#{supervisor}")
+            puts "Kill self supervisor is gone"
+            Process.kill "TERM", Process.pid
+          end
+          sleep 2
+        end
+      end
+    end
+
   end
 
   ActiveRecord::Base.connection.disconnect!

config/unicorn_launcher

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# This is a helper script you can use to supervise unicorn, it allows you to perform a live restart
+# by sending it a USR2 signal
+
+LOCAL_WEB="http://127.0.0.1:3000/"
+
+function on_exit()
+{
+  kill $UNICORN_PID
+  echo "exiting"
+}
+
+function on_reload()
+{
+  echo "Reloading unicorn"
+  kill -s USR2 $UNICORN_PID
+  sleep 10
+  curl $LOCAL_WEB &> /dev/null
+  NEW_UNICORN_PID=`ps -f --ppid $UNICORN_PID | grep unicorn | grep -v worker | awk '{ print $2 }'`
+  kill $UNICORN_PID
+  echo "Old pid is: $UNICORN_PID New pid is: $NEW_UNICORN_PID"
+  UNICORN_PID=$NEW_UNICORN_PID
+}
+
+export UNICORN_SUPERVISOR_PID=$$
+
+trap on_exit EXIT
+trap on_reload USR2
+
+unicorn -c $1 &
+UNICORN_PID=$!
+
+echo "supervisor pid: $UNICORN_SUPERVISOR_PID unicorn pid: $UNICORN_PID"
+
+while [ -e /proc/$UNICORN_PID ]
+do
+  sleep 0.1
+done