unicorn fix

config/deploy.rb

@@ -45,7 +45,8 @@ end
 namespace :deploy do
   desc "Restarting mod_rails with restart.txt"
   task :restart, :roles => :app, :except => { :no_release => true } do
-    run "cd #{deploy_to}/current ; ([ -f tmp/pids/unicorn.pid ] && kill -USR2 `cat tmp/pids/unicorn.pid`); true"
+    ## DISABLED: run "cd #{deploy_to}/current ; ([ -f tmp/pids/unicorn.pid ] && kill -USR2 `cat tmp/pids/unicorn.pid`); true"
+    run ["#{current_path}/script/unicorn reload"].join("; ")
     restart_dj
   end
 

config/unicorn.rb

@@ -53,22 +53,35 @@ before_fork do |server, worker|
   end
 end
 
+before_fork do |server, worker|
+  ##
+  # When sent a USR2, Unicorn will suffix its pidfile with .oldbin and
+  # immediately start loading up a new version of itself (loaded with a new
+  # version of our app). When this new Unicorn is completely loaded
+  # it will begin spawning workers. The first worker spawned will check to
+  # see if an .oldbin pidfile exists. If so, this means we've just booted up
+  # a new Unicorn and need to tell the old one that it can now die. To do so
+  # we send it a QUIT.
+  #
+  # Using this method we get 0 downtime deploys.
+  old_pid = File.expand_path(File.join(File.dirname(__FILE__), "..")) + '/tmp/pids/unicorn.pid.oldbin'
+  if File.exists?(old_pid) && server.pid != old_pid
+    begin
+      Process.kill("QUIT", File.read(old_pid).to_i)
+    rescue Errno::ENOENT, Errno::ESRCH
+      # someone else did our job for us
+    end
+  end
 
-#before_fork do |server, worker|
-#  # the following is highly recomended for Rails + "preload_app true"
-#  # as there's no need for the master process to hold a connection
-#  defined?(ActiveRecord::Base) and
-#    ActiveRecord::Base.connection.disconnect!
-#end
+  # This option works in together with preload_app true setting
+  # What is does is prevent the master process from holding
+  # the database connection
+  defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect!
+end
 
 after_fork do |server, worker|
-  # per-process listener ports for debugging/admin/migrations
-  # addr = "127.0.0.1:#{9293 + worker.nr}"
-  # server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)
-
-  # the following is *required* for Rails + "preload_app true",
-  defined?(ActiveRecord::Base) and
-    ActiveRecord::Base.establish_connection
+  # Here we are establishing the connection after forking worker processes
+  defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection
 
   # if preload_app is true, then you may also want to check and
   # restart any other shared sockets/descriptors such as Memcached,

script/unicorn

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+current_path="/var/www/rosa_build"
+
+
+getpid() {
+    pid=`ps ax |grep "unicorn_rails master -c /var/www/rosa_build" \
+           |grep -v grep \
+           |awk '{print $1}'`;
+}
+
+
+start() {
+    export RUBY_HEAP_MIN_SLOTS=1400000
+    export RUBY_HEAP_SLOTS_INCREMENT=500000
+    export RUBY_HEAP_SLOTS_GROWTH_FACTOR=1
+    export RUBY_GC_MALLOC_LIMIT=30000000
+    export RUBY_HEAP_FREE_MIN=12500
+
+    cd $current_path && \
+    bundle exec unicorn_rails -c $current_path/config/unicorn.rb -E production -D
+}
+
+
+stop() {
+    while : ; do
+        getpid;
+        if [ x"$pid" != x"" ] ; then
+            kill $pid;
+            sleep 1;
+        else
+            break;
+        fi
+    done
+}
+
+
+reload() {
+    getpid;
+    if [ x"$pid" != x"" ] ; then
+        kill -USR2 $pid;
+    else
+        start;
+    fi
+}
+
+
+case "$1" in
+  start)
+        start
+        ;;
+  stop)
+        stop;
+        ;;
+  reload)
+        reload
+        ;;
+  *)
+        echo $"Usage: $0 {start|stop|reload}"
+        exit 2
+esac