refactor(teleop): Use queue instead of locks for keyboard teleop

lerobot/common/teleoperators/keyboard/teleop_keyboard.py

@@ -18,7 +18,7 @@
 import os
 import sys
 import time
-from threading import Lock
+from queue import Queue
 
 import numpy as np
 
@@ -29,7 +29,6 @@
 
 PYNPUT_AVAILABLE = True
 try:
-    # Only import if there's a valid X server or if we're not on a Pi
     if ("DISPLAY" not in os.environ) and ("linux" in sys.platform):
         logging.info("No DISPLAY set. Skipping pynput import.")
         raise ImportError("pynput blocked intentionally due to no display.")
@@ -57,15 +56,14 @@ def __init__(self, config: KeyboardTeleopConfig):
         self.config = config
         self.robot_type = config.type
 
-        self.pressed_keys_lock = Lock()
-        self.pressed_keys = {}
+        self.event_queue = Queue()
+        self.current_pressed = {}
         self.listener = None
         self.is_connected = False
         self.logs = {}
 
     @property
     def action_feature(self) -> dict:
-        # TODO(Steven): Set this from config? (when deciding the keys we want to capture)
         return {
             "dtype": "float32",
             "shape": (len(self.arm),),
@@ -100,17 +98,20 @@ def calibrate(self) -> None:
 
     def on_press(self, key):
         if hasattr(key, "char"):
-            with self.pressed_keys_lock:
-                self.pressed_keys[key.char] = True
+            self.event_queue.put((key.char, True))
 
     def on_release(self, key):
         if hasattr(key, "char"):
-            with self.pressed_keys_lock:
-                self.pressed_keys[key.char] = False
+            self.event_queue.put((key.char, False))
         if key == keyboard.Key.esc:
             logging.info("ESC pressed, disconnecting.")
             self.disconnect()
 
+    def _drain_pressed_keys(self):
+        while not self.event_queue.empty():
+            key_char, is_pressed = self.event_queue.get_nowait()
+            self.current_pressed[key_char] = is_pressed
+
     def get_action(self) -> np.ndarray:
         before_read_t = time.perf_counter()
 
@@ -119,10 +120,10 @@ def get_action(self) -> np.ndarray:
                 "KeyboardTeleop is not connected. You need to run `connect()` before `get_action()`."
             )
 
-        with self.pressed_keys_lock:
-            pressed_keys_snapshot = self.pressed_keys
+        self._drain_pressed_keys()
 
-        action = {key for key, val in pressed_keys_snapshot.items() if val}
+        # Generate action based on current key states
+        action = {key for key, val in self.current_pressed.items() if val}
         self.logs["read_pos_dt_s"] = time.perf_counter() - before_read_t
 
         return np.array(list(action))