Unicorn: shut down old master upon first fork

After the first child forks, shut down the old master. Previously, the old master and it's workers would jut sit there forever. See: https://github.com/blog/517-unicorn https://github.com/sosedoff/capistrano-unicorn/blob/master/examples/rails3.rb#L30 Tested in production.

Unicorn: shut down old master upon first fork
After the first child forks, shut down the old master. Previously, the old master and it's workers would jut sit there forever. See: https://github.com/blog/517-unicorn https://github.com/sosedoff/capistrano-unicorn/blob/master/examples/rails3.rb#L30 Tested in production.
Daniel Beardsley
1 parent 34a4b8a1
Showing 1 changed file with 24 additions and 0 deletions Show diff stats
config/unicorn.rb
@@ -3,3 +3,27 @@
 worker_processes 3 # amount of unicorn workers to spin up
 timeout 30         # restarts workers that hang for 30 seconds
 preload_app true
+
+# Taken from github: https://github.com/blog/517-unicorn
+# Though everyone uses pretty miuch the same code
+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 = "#{server.config[: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
+end
...	...	@@ -3,3 +3,27 @@
3	3	worker_processes 3 # amount of unicorn workers to spin up
4	4	timeout 30 # restarts workers that hang for 30 seconds
5	5	preload_app true
	6	+
	7	+# Taken from github: https://github.com/blog/517-unicorn
	8	+# Though everyone uses pretty miuch the same code
	9	+before_fork do \|server, worker\|
	10	+ ##
	11	+ # When sent a USR2, Unicorn will suffix its pidfile with .oldbin and
	12	+ # immediately start loading up a new version of itself (loaded with a new
	13	+ # version of our app). When this new Unicorn is completely loaded
	14	+ # it will begin spawning workers. The first worker spawned will check to
	15	+ # see if an .oldbin pidfile exists. If so, this means we've just booted up
	16	+ # a new Unicorn and need to tell the old one that it can now die. To do so
	17	+ # we send it a QUIT.
	18	+ #
	19	+ # Using this method we get 0 downtime deploys.
	20	+
	21	+ old_pid = "#{server.config[:pid]}.oldbin"
	22	+ if File.exists?(old_pid) && server.pid != old_pid
	23	+ begin
	24	+ Process.kill("QUIT", File.read(old_pid).to_i)
	25	+ rescue Errno::ENOENT, Errno::ESRCH
	26	+ # someone else did our job for us
	27	+ end
	28	+ end
	29	+end
...	...