MAJOR: BUGFIX: Robot class doesn't delete the persistent robot connec…

…tion. It relises on the user to close the persistent connection (by calling robot.close() on atleast one of the robot instances) before existing the program. Skipping this for sim-robot shouldn't be a problem. For hardware robot it will leave the robot running. This cleans up the bug that was preventing clean termination

robohive/robot/robot.py

@@ -37,7 +37,7 @@ class Robot():
     """
     A unified viewpoint of robot between simulation(sim) and hardware(hdr)
     """
-    # Cached robot that is shared for the application lifetime.
+    # Cached a persistent connection to the robot that is shared for the application's lifetime.
     robot_config = None
 
     def __init__(self,
@@ -780,9 +780,14 @@ def reset(self,
         return feasibe_pos, feasibe_vel
 
 
-    # close connection and exit out of the robot
+    # Clear the robot class. Note that it doesn't close the persistent connection
+    def __del__(self):
+        if self.robot_config is not None and self.is_hardware:
+            raise RuntimeWarning("RoboHive:> Robot class is being cleared from the workspace. This is expected if we still need to maintain the active connection to the hardware. A persistent connection to robot is still maintained and will be used next time a robot class is created. Ensure that a robot.close() is called to terminate the persistent connection before exiting the program.")
+
+    # Close the persistnent connection to the robot. This should be called only once at the end when persistent connection is no longer needed.
     def close(self):
-        if self.robot_config:
+        if self.robot_config is not None:
             status = self.hardware_close() if self.is_hardware else True
             if status:
                 prompt(f"Closed {self.name} (Status: {status})", 'white', 'on_grey', flush=True)
@@ -793,11 +798,6 @@ def close(self):
             prompt(f"Trying to close a non-existent robot", flush=True, type=Prompt.WARN)
 
 
-    # destructor
-    def __del__(self):
-        self.close()
-
-
 def demo_robot():
     from robohive.utils import gym
 

robohive/utils/prompt_utils.py

@@ -61,17 +61,6 @@ def prompt(data, color=None, on_color=None, flush=False, end="\n", type:Prompt=P
 
     global PROMPT_CACHE
 
-    # Why is cprint None during exit? HACK as a workaround for now
-    if cprint is None:
-        # cprint(data, color=color, on_color=on_color, flush=flush, end=end) # throws error
-        print(data, flush=flush, end=end)
-
-    # Why is Prompt None during exit? HACK as a workaround for now
-    if Prompt is None:
-        # print(Prompt.ONCE, "=============", type, flush=True) # throws error
-        print(data, flush=flush, end=end)
-        return
-
     if type == Prompt.ONCE:
         data_hash = hash(data)
         if data_hash in PROMPT_CACHE: