Communication: Use zmq.Poller() rather than waiting infinitely (#789)

* Communication: Use zmq.Poller() rather than waiting infinitely

* Format black

* fix spelling

* Add test

---------

Co-authored-by: pyiron-runner <pyiron@mpie.de>

Author: jan-janssen

executorlib/standalone/interactive/communication.py

@@ -1,35 +1,46 @@
 import logging
 import sys
 from socket import gethostname
-from typing import Optional
+from typing import Any, Optional
 
 import cloudpickle
 import zmq
 
 
+class ExecutorlibSocketError(RuntimeError):
+    pass
+
+
 class SocketInterface:
     """
     The SocketInterface is an abstraction layer on top of the zero message queue.
 
     Args:
         spawner (executorlib.shared.spawner.BaseSpawner): Interface for starting the parallel process
         log_obj_size (boolean): Enable debug mode which reports the size of the communicated objects.
+        time_out_ms (int): Time out for waiting for a message on socket in milliseconds.
     """
 
-    def __init__(self, spawner=None, log_obj_size=False):
+    def __init__(
+        self, spawner=None, log_obj_size: bool = False, time_out_ms: int = 1000
+    ):
         """
         Initialize the SocketInterface.
 
         Args:
             spawner (executorlib.shared.spawner.BaseSpawner): Interface for starting the parallel process
+            log_obj_size (boolean): Enable debug mode which reports the size of the communicated objects.
+            time_out_ms (int): Time out for waiting for a message on socket in milliseconds.
         """
         self._context = zmq.Context()
         self._socket = self._context.socket(zmq.PAIR)
+        self._poller = zmq.Poller()
+        self._poller.register(self._socket, zmq.POLLIN)
         self._process = None
+        self._time_out_ms = time_out_ms
+        self._logger: Optional[logging.Logger] = None
         if log_obj_size:
             self._logger = logging.getLogger("executorlib")
-        else:
-            self._logger = None
         self._spawner = spawner
 
     def send_dict(self, input_dict: dict):
@@ -52,7 +63,12 @@ def receive_dict(self) -> dict:
         Returns:
             dict: dictionary with response received from the connected client
         """
-        data = self._socket.recv()
+        response_lst: list[tuple[Any, int]] = []
+        while len(response_lst) == 0:
+            response_lst = self._poller.poll(self._time_out_ms)
+            if not self._spawner.poll():
+                raise ExecutorlibSocketError()
+        data = self._socket.recv(zmq.NOBLOCK)
         if self._logger is not None:
             self._logger.warning(
                 "Received dictionary of size: " + str(sys.getsizeof(data))

tests/test_standalone_interactive_communication.py

@@ -12,6 +12,7 @@
     interface_send,
     interface_receive,
     SocketInterface,
+    ExecutorlibSocketError,
 )
 from executorlib.standalone.serialize import cloudpickle_register
 from executorlib.standalone.interactive.spawner import MpiExecSpawner
@@ -114,6 +115,35 @@ def test_interface_serial_with_debug(self):
         )
         interface.shutdown(wait=True)
 
+    def test_interface_serial_with_stopped_process(self):
+        cloudpickle_register(ind=1)
+        task_dict = {"fn": calc, "args": (), "kwargs": {"i": 2}}
+        interface = SocketInterface(
+            spawner=MpiExecSpawner(cwd=None, cores=1, openmpi_oversubscribe=False),
+            log_obj_size=True,
+        )
+        interface.bootup(
+            command_lst=[
+                sys.executable,
+                os.path.abspath(
+                    os.path.join(
+                        __file__,
+                        "..",
+                        "..",
+                        "executorlib",
+                        "backend",
+                        "interactive_serial.py",
+                    )
+                ),
+                "--zmqport",
+                str(interface.bind_to_random_port()),
+            ]
+        )
+        interface.send_dict(input_dict=task_dict)
+        interface._spawner._process.terminate()
+        with self.assertRaises(ExecutorlibSocketError):
+            interface.receive_dict()
+
 
 class TestZMQ(unittest.TestCase):
     def test_interface_receive(self):