implement TSTP handling (#492)

lib/shoryuken/runner.rb

@@ -19,7 +19,7 @@ class Runner
     def run(options)
       self_read, self_write = IO.pipe
 
-      %w(INT TERM USR1 TTIN).each do |sig|
+      %w(INT TERM USR1 TSTP TTIN).each do |sig|
         begin
           trap sig do
             self_write.puts(sig)
@@ -106,6 +106,12 @@ def execute_soft_shutdown
       exit 0
     end
 
+    def execute_terminal_stop
+      logger.info { 'Received TSTP, will stop accepting new work' }
+
+      @launcher.stop
+    end
+
     def print_threads_backtrace
       Thread.list.each do |thread|
         logger.info { "Thread TID-#{thread.object_id.to_s(36)} #{thread['label']}" }
@@ -123,8 +129,9 @@ def handle_signal(sig)
       case sig
       when 'USR1' then execute_soft_shutdown
       when 'TTIN' then print_threads_backtrace
+      when 'TSTP' then execute_terminal_stop
       when 'TERM', 'INT'
-        logger.info { "Received #{sig}, will shutdown down" }
+        logger.info { "Received #{sig}, will shutdown" }
 
         raise Interrupt
       end