Implement worker suspend/resume

Bump to 0.0.39

Author: smathot

examples/example_single_editor.py

@@ -2,9 +2,12 @@
 import os
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 from pyqt_code_editor import watchdog
-from qtpy.QtWidgets import QApplication, QVBoxLayout, QWidget
+from qtpy.QtWidgets import QApplication, QVBoxLayout, QWidget, QShortcut
+from qtpy.QtGui import QKeySequence
+from qtpy.QtCore import Qt
 from pyqt_code_editor.code_editors import create_editor
 from pyqt_code_editor.environment_manager import environment_manager
+from pyqt_code_editor.worker import manager
 import logging
 logging.basicConfig(level=logging.INFO, force=True)
 
@@ -19,6 +22,23 @@ def __init__(self, path=None):
         layout.addWidget(self.editor)
         self.setLayout(layout)
 
+        # Keyboard shortcuts for suspending/resuming workers
+        self.suspend_shortcut = QShortcut(QKeySequence("Ctrl+T"), self)
+        self.suspend_shortcut.setContext(Qt.ApplicationShortcut)
+        self.suspend_shortcut.activated.connect(self.suspend_workers)
+
+        self.resume_shortcut = QShortcut(QKeySequence("Ctrl+Y"), self)
+        self.resume_shortcut.setContext(Qt.ApplicationShortcut)
+        self.resume_shortcut.activated.connect(self.resume_workers)
+
+    def suspend_workers(self):
+        logging.info("Suspending worker processes")
+        manager.suspend()
+
+    def resume_workers(self):
+        logging.info("Resuming worker processes")
+        manager.resume()
+
     def closeEvent(self, event):
         watchdog.shutdown()
         super().closeEvent(event)
@@ -31,4 +51,4 @@ def closeEvent(self, event):
         path = sys.argv[1]    
     win = MainWindow(path)
     win.show()
-    sys.exit(app.exec_())
+    sys.exit(app.exec_())

pyqt_code_editor/__init__.py

@@ -2,4 +2,4 @@
 
 from ._settings import settings
 
-__version__ = '0.0.38'
+__version__ = '0.0.39'

pyqt_code_editor/mixins/base.py

@@ -74,6 +74,9 @@ def send_worker_request(self, **data):
         so we can handle multiple concurrent requests.
         """
         result_queue, pid = manager.send_worker_request(**data)
+        if result_queue is None:
+            logger.info('Request ignored')
+            return
         self._active_requests[pid] = result_queue
         logger.info(f"Sent request to worker {pid}, now tracking {len(self._active_requests)} active requests.")
 

pyqt_code_editor/worker/manager.py

@@ -7,6 +7,7 @@
 STOP_UNUSED_INTERVAL = 10
 _last_stop_unused_time = 0
 _workers = {}  # pid -> {"process", "request_queue", "result_queue", "is_free"}
+suspended = False
 
 
 def send_worker_request(**data) -> (Queue, int):
@@ -16,7 +17,11 @@ def send_worker_request(**data) -> (Queue, int):
 
     The caller can poll the result_queue for responses, and once done,
     call mark_worker_as_free(pid) to release this worker for future use.
+    
+    If workers are suspended, return (None, None).
     """
+    if suspended:
+        return None, None
     # 1. Look for an existing free worker
     for pid, w in list(_workers.items()):
         if w["is_free"] and w["process"].is_alive():
@@ -100,7 +105,7 @@ def stop_all_workers():
     """
     Cleanly shut down all worker processes.
     """
-    logger.info("Stopping all worker processes...")
+    logger.info(f"Stopping {len(_workers)} worker processes...")
     for pid, w in list(_workers.items()):
         if w["process"].is_alive():
             logger.info(f"Stopping worker {pid}.")
@@ -116,4 +121,23 @@ def update_setting(name, value):
     for pid, w in _workers.items():
         if w["process"].is_alive():
             w["request_queue"].put(settings_action)            
+            
+            
+def suspend():
+    """Stops all worker processes and ignores all requests until resume() is 
+    called.
+    """
+    global suspended
+    suspended = True
+    logger.info("Suspending worker processes...")
+    stop_all_workers()
+    
+    
+def resume():
+    """Resumes accepting requests."""
+    global suspended
+    suspended = False
+    logger.info("Resuming worker processes...")
+
+            
 settings.setting_changed.connect(update_setting)