fix(cli): added gui heartbeat

bec_widgets/cli/client_utils.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import importlib
 import select
 import subprocess
+import time
 import uuid
 from functools import wraps
 from typing import TYPE_CHECKING
@@ -32,6 +33,8 @@ def rpc_call(func):
 
     @wraps(func)
     def wrapper(self, *args, **kwargs):
+        if not self.gui_is_alive():
+            raise RuntimeError("GUI is not alive")
         return self._run_rpc(func.__name__, *args, **kwargs)
 
     return wrapper
@@ -135,6 +138,9 @@ class BECFigureClientMixin:
         """
         if self._process is None or self._process.poll() is not None:
             self._start_plot_process()
+        while not self.gui_is_alive():
+            print("Waiting for GUI to start...")
+            time.sleep(0.5)
 
     def close(self) -> None:
         """
@@ -266,9 +272,16 @@ class RPCBase:
         Wait for the response from the server.
         """
         response = None
-        while response is None:
+        while response is None and self.gui_is_alive():
             response = self._client.connector.get(
                 MessageEndpoints.gui_instruction_response(request_id)
             )
             QCoreApplication.processEvents()  # keep UI responsive (and execute signals/slots)
         return response
+
+    def gui_is_alive(self):
+        """
+        Check if the GUI is alive.
+        """
+        heart = self._client.connector.get(MessageEndpoints.gui_heartbeat(self._root._gui_id))
+        return heart is not None

bec_widgets/cli/server.py

@@ -1,11 +1,13 @@
 import inspect
+import threading
+import time
 
 from bec_lib import MessageEndpoints, messages
 
 from bec_widgets.utils import BECDispatcher
 from bec_widgets.utils.bec_connector import BECConnector
 from bec_widgets.widgets.figure import BECFigure
-from bec_widgets.widgets.plots import BECCurve, BECWaveform1D, BECImageShow
+from bec_widgets.widgets.plots import BECCurve, BECImageShow, BECWaveform1D
 
 
 class BECWidgetsCLIServer:
@@ -18,10 +20,12 @@ class BECWidgetsCLIServer:
         self.gui_id = gui_id
         self.fig = BECFigure(gui_id=self.gui_id)
         # print(f"Server started with gui_id {self.gui_id}")
-
+        self._shutdown_event = threading.Event()
         self.dispatcher.connect_slot(
             self.on_rpc_update, MessageEndpoints.gui_instructions(self.gui_id)
         )
+        self._heartbeat = threading.Thread(target=self.start_heartbeat, daemon=True)
+        self._heartbeat.start()
 
     def start(self):
         """Start the figure window."""
@@ -95,10 +99,20 @@ class BECWidgetsCLIServer:
             }
         return obj
 
+    def start_heartbeat(self):
+        while not self._shutdown_event.is_set():
+            self.client.connector.set(
+                MessageEndpoints.gui_heartbeat(self.gui_id),
+                messages.StatusMessage(name=self.gui_id, status=1, info={}),
+                expire=10,
+            )
+            time.sleep(3)
+
 
 if __name__ == "__main__":  # pragma: no cover
     import argparse
     import sys
+
     from qtpy.QtWidgets import QApplication
 
     app = QApplication(sys.argv)