fix: add event to avoid deadlocks on run_command calls

src/pykiso/interfaces/dt_auxiliary.py

@@ -78,6 +78,7 @@ def __init__(
         self.is_proxy_capable = is_proxy_capable
         self.auto_start = auto_start
         self.lock = threading.RLock()
+        self._stop_event = threading.Event()
         self.stop_tx = threading.Event()
         self.stop_rx = threading.Event()
         self.queue_in = queue.Queue()
@@ -116,6 +117,11 @@ def run_command(
         :return: True if the request is correctly executed otherwise
             False
         """
+        # avoid a deadlock in case run_command is called within a _receive_message implementation
+        # (for e.g. callback implementation) while delete_instance is being executed from the main thread
+        if self._stop_event.is_set():
+            return timeout_result
+
         with self.lock:
             if not self.is_instance:
                 raise AuxiliaryNotStarted(self.name)
@@ -171,10 +177,11 @@ def delete_instance(self) -> bool:
         log.internal_info(f"Deleting instance of auxiliary {self.name}")
 
         with self.lock:
-            # if the current aux is not alive don't try to delete it
-            # again
+            self._stop_event.set()
+            # if the current aux is not alive don't try to delete it again
             if not self.is_instance:
                 log.internal_info(f"Auxiliary {self.name} is already deleted")
+                self._stop_event.clear()
                 return True
 
             # stop each auxiliary's tasks
@@ -189,6 +196,7 @@ def delete_instance(self) -> bool:
                 )
 
             self.is_instance = False
+            self._stop_event.clear()
             return is_deleted
 
     def _start_tx_task(self) -> None:

tests/test_dt_auxiliary_interface.py

@@ -277,6 +277,28 @@ def test_run_command(mocker, aux_inst):
     assert value == b"\x02"
 
 
+def test_run_command_stop_event_set(mocker, aux_inst):
+    queue_put = mocker.patch.object(aux_inst.queue_in, "put")
+    queue_get = mocker.patch.object(aux_inst.queue_out, "get", return_value=b"\x02")
+
+    aux_inst.is_instance = True
+    aux_inst._stop_event.set()
+
+    value = aux_inst.run_command(
+        cmd_message="send",
+        cmd_data=b"\x01",
+        blocking=False,
+        timeout_in_s=0,
+        timeout_result="dummy",
+    )
+
+    aux_inst._stop_event.clear()
+
+    assert queue_get.call_count == 0
+    assert queue_put.call_count == 0
+    assert value == "dummy"
+
+
 def test_run_command_timeout(mocker, aux_inst):
     queue_put = mocker.patch.object(aux_inst.queue_in, "put")