Add experimental support for Puma

This allows us (and others) to test drive Puma without it affecting all
users. Puma can be enabled by setting the environment variable
"EXPERIMENTAL_PUMA" to a non empty value.

1 files changed, 48 insertions, 19 deletions

diff --git a/config/unicorn.rb.example.development b/config/unicorn.rb.example.development
index f31df66015a..f7541bb9d55 100644
--- a/config/unicorn.rb.example.development
+++ b/config/unicorn.rb.example.development
@@ -1,32 +1,61 @@
+# frozen_string_literal: true
+
+# -------------------------------------------------------------------------
+# This file is used by the GDK to generate a default config/unicorn.rb file
+# Note that `/home/git` will be substituted for the actual GDK root
+# directory when this file is generated
+# -------------------------------------------------------------------------
+
 worker_processes 2
 timeout 60
 
+listen '/home/git/gitlab.socket'
+
 preload_app true
 check_client_connection false
 
+require_relative "/home/git/gitlab/lib/gitlab/cluster/lifecycle_events"
+
+before_exec do |server|
+  # Signal application hooks that we're about to restart
+  Gitlab::Cluster::LifecycleEvents.do_master_restart
+end
+
 before_fork do |server, worker|
-  # the following is highly recommended for Rails + "preload_app true"
-  # as there's no need for the master process to hold a connection
-  defined?(ActiveRecord::Base) &&
-    ActiveRecord::Base.connection.disconnect!
-
-  if /darwin/ =~ RUBY_PLATFORM
-    require 'fiddle'
-
-    # Dynamically load Foundation.framework, ~implicitly~ initialising
-    # the Objective-C runtime before any forking happens in Unicorn
-    #
-    # From https://bugs.ruby-lang.org/issues/14009
-    Fiddle.dlopen '/System/Library/Frameworks/Foundation.framework/Foundation'
+  # Signal application hooks that we're about to fork
+  Gitlab::Cluster::LifecycleEvents.do_before_fork
+
+  # The following is only recommended for memory/DB-constrained
+  # installations.  It is not needed if your system can house
+  # twice as many worker_processes as you have configured.
+  #
+  # This allows a new master process to incrementally
+  # phase out the old master process with SIGTTOU to avoid a
+  # thundering herd (especially in the "preload_app false" case)
+  # when doing a transparent upgrade.  The last worker spawned
+  # will then kill off the old master process with a SIGQUIT.
+  old_pid = "#{server.config[:pid]}.oldbin"
+  if old_pid != server.pid
+    begin
+      sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
+      Process.kill(sig, File.read(old_pid).to_i)
+    rescue Errno::ENOENT, Errno::ESRCH
+    end
   end
+  #
+  # Throttle the master from forking too quickly by sleeping.  Due
+  # to the implementation of standard Unix signal handlers, this
+  # helps (but does not completely) prevent identical, repeated signals
+  # from being lost when the receiving process is busy.
+  # sleep 1
 end
 
 after_fork do |server, worker|
-  # Unicorn clears out signals before it forks, so rbtrace won't work
-  # unless it is enabled after the fork.
-  require 'rbtrace' if ENV['ENABLE_RBTRACE']
+  # Signal application hooks of worker start
+  Gitlab::Cluster::LifecycleEvents.do_worker_start
 
-  # the following is *required* for Rails + "preload_app true",
-  defined?(ActiveRecord::Base) &&
-    ActiveRecord::Base.establish_connection
+  # 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)
 end
+