Add special INT handler for gevent, and fix TERM behavior as well.

Refs #755

huey/consumer.py

@@ -497,15 +497,33 @@ def check_worker_health(self):
 
     def _set_signal_handlers(self):
         signal.signal(signal.SIGTERM, self._handle_stop_signal)
-        signal.signal(signal.SIGINT, signal.default_int_handler)
+        if self.worker_type == WORKER_GREENLET:
+            # Add a special INT handler when using gevent. If the running
+            # greenlet is not the main hub, then Gevent will raise a
+            # KeyboardInterrupt in the running greenlet by default. This
+            # ensures that when INT is received we properly flag the main loop
+            # for graceful shutdown and do NOT propagate the exception.
+            signal.signal(signal.SIGINT, self._handle_interrupt_signal_gevent)
+        else:
+            signal.signal(signal.SIGINT, signal.default_int_handler)
         if hasattr(signal, 'SIGHUP'):
             signal.signal(signal.SIGHUP, self._handle_restart_signal)
 
+    def _handle_interrupt_signal_gevent(self, sig_num, frame):
+        self._logger.info('Received SIGINT')
+        self._received_signal = True
+        self._restart = False
+        self._graceful = True
+        signal.signal(signal.SIGINT, signal.default_int_handler)
+
     def _handle_stop_signal(self, sig_num, frame):
         self._logger.info('Received SIGTERM')
         self._received_signal = True
         self._restart = False
         self._graceful = False
+        if self.worker_type == WORKER_GREENLET:
+            # Ensure that the running greenlet (if not main) is interrupted.
+            raise KeyboardInterrupt
 
     def _handle_restart_signal(self, sig_num, frame):
         self._logger.info('Received SIGHUP, will restart')