Use selectors instead of select

oec/controller.py

@@ -5,7 +5,7 @@ oec.controller
 
 import time
 import logging
-from select import select
+import selectors
 from coax import poll, poll_ack, load_control_register, get_features, PollAction, \
                  KeystrokePollResponse, TerminalType, ReceiveTimeout, \
                  ReceiveError, ProtocolError
@@ -29,6 +29,8 @@ class Controller:
         self.terminal = None
         self.session = None
 
+        self.session_selector = None
+
         # Target time between POLL commands in seconds when a terminal is connected or
         # no terminal is connected.
         #
@@ -45,11 +47,17 @@ class Controller:
         """Run the controller."""
         self.running = True
 
+        self.session_selector = selectors.DefaultSelector()
+
         while self.running:
             self._run_loop()
 
         self._terminate_session()
 
+        self.session_selector.close()
+
+        self.session_selector = None
+
         if self.terminal:
             self.terminal = None
 
@@ -139,7 +147,7 @@ class Controller:
     def _handle_session_disconnected(self):
         self.logger.info('Session disconnected')
 
-        self.session = None
+        self._terminate_session()
 
         # Restart the session.
         self._start_session()
@@ -149,10 +157,14 @@ class Controller:
 
         self.session.start()
 
+        self.session_selector.register(self.session, selectors.EVENT_READ)
+
     def _terminate_session(self):
         if not self.session:
             return
 
+        self.session_selector.unregister(self.session)
+
         self.session.terminate()
 
         self.session = None
@@ -161,10 +173,15 @@ class Controller:
         while duration > 0:
             start_time = time.perf_counter()
 
-            if self.session not in select([self.session], [], [], duration)[0]:
+            selected = self.session_selector.select(duration)
+
+            if not selected:
                 break
 
-            self.session.handle_host()
+            for (key, events) in selected:
+                session = key.fileobj
+
+                session.handle_host()
 
             duration -= (time.perf_counter() - start_time)
 

requirements.txt

@@ -2,7 +2,7 @@ ptyprocess==0.7.0
 pycoax==0.6.0
 pyserial==3.5
 pyte==0.8.0
-pytn3270==0.9.0
+pytn3270==0.9.1
 sliplib==0.6.2
 sortedcontainers==2.3.0
 wcwidth==0.2.5

tests/test_controller.py

@@ -1,3 +1,4 @@
+import selectors
 import unittest
 from unittest.mock import Mock, PropertyMock, patch
 from coax import PollAction, PowerOnResetCompletePollResponse, KeystrokePollResponse, ReceiveTimeout
@@ -26,6 +27,8 @@ class RunLoopTestCase(unittest.TestCase):
 
         self.controller.connected_poll_period = 1
 
+        self.controller.session_selector = Mock()
+
         self.controller._update_session = Mock()
 
         patcher = patch('oec.controller.poll')
@@ -257,14 +260,12 @@ class UpdateSessionTestCase(unittest.TestCase):
 
         self.controller.session = Mock()
 
+        self.controller.session_selector = Mock()
+
         patcher = patch('oec.controller.time.perf_counter')
 
         self.perf_counter_mock = patcher.start()
 
-        patcher = patch('oec.controller.select')
-
-        self.select_mock = patcher.start()
-
     def test_zero_duration(self):
         # Act
         self.controller._update_session(0)
@@ -272,11 +273,11 @@ class UpdateSessionTestCase(unittest.TestCase):
         # Assert
         self.controller.session.handle_host.assert_not_called()
 
-        self.select_mock.assert_not_called()
+        self.controller.session_selector.select.assert_not_called()
 
     def test_select_timeout(self):
         # Arrange
-        self.select_mock.return_value = ([], [], [])
+        self.controller.session_selector.select.return_value = []
 
         # Act
         self.controller._update_session(1)
@@ -284,13 +285,15 @@ class UpdateSessionTestCase(unittest.TestCase):
         # Assert
         self.controller.session.handle_host.assert_not_called()
 
-        self.select_mock.assert_called_once()
+        self.controller.session_selector.select.assert_called_once()
 
     def test_select_available(self):
         # Arrange
         self.perf_counter_mock.side_effect = [0, 0.75, 0.75]
 
-        self.select_mock.side_effect = [([self.controller.session], [], []), ([], [], [])]
+        selector_key = Mock(fileobj=self.controller.session)
+
+        self.controller.session_selector.select.side_effect = [[(selector_key, selectors.EVENT_READ)], []]
 
         # Act
         self.controller._update_session(1)
@@ -298,7 +301,9 @@ class UpdateSessionTestCase(unittest.TestCase):
         # Assert
         self.controller.session.handle_host.assert_called_once()
 
-        self.assertEqual(self.select_mock.call_count, 2)
+        self.assertEqual(self.controller.session_selector.select.call_count, 2)
 
-        self.assertEqual(self.select_mock.call_args_list[0][0][3], 1)
-        self.assertEqual(self.select_mock.call_args_list[1][0][3], 0.25)
+        call_args_list = self.controller.session_selector.select.call_args_list
+
+        self.assertEqual(call_args_list[0][0][0], 1)
+        self.assertEqual(call_args_list[1][0][0], 0.25)