Unicorn handle forked db connections - fixes PG::Error SSL SYSCALL error: EOF detected

config/unicorn.rb

@@ -1,3 +1,27 @@
 preload_app true   # https://newrelic.com/docs/ruby/no-data-with-unicorn
 worker_processes 4 # amount of unicorn workers to spin up
 timeout 30         # restarts workers that hang for 30 seconds
+
+
+# https://devcenter.heroku.com/articles/forked-pg-connections
+before_fork do |server, worker|
+
+  Signal.trap 'TERM' do
+    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
+    Process.kill 'QUIT', Process.pid
+  end
+
+  defined?(ActiveRecord::Base) and
+    ActiveRecord::Base.connection.disconnect!
+end
+
+after_fork do |server, worker|
+
+  Signal.trap 'TERM' do
+    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to sent QUIT'
+  end
+
+  defined?(ActiveRecord::Base) and
+    ActiveRecord::Base.establish_connection
+
+end