Merge pull request #42 from arduino/thread_locks

Improved threading
- Thread locks on methods accessing UART

Author: eigen-value

arduino_alvik/__init__.py

@@ -4,8 +4,8 @@
 
 __author__ = "Lucio Rossi <[email protected]>, Giovanni Bruno <[email protected]>"
 __license__ = "MPL 2.0"
-__version__ = "1.1.2"
+__version__ = "1.1.3"
 __maintainer__ = "Lucio Rossi <[email protected]>, Giovanni Bruno <[email protected]>"
-__required_firmware_version__ = "1.1.0"
+__required_firmware_version__ = "1.1.1"
 
 from .arduino_alvik import *

arduino_alvik/arduino_alvik.py

@@ -16,12 +16,72 @@
 from .__init__ import __required_firmware_version__
 
 
+def writes_uart(method):
+    def wrapper(*args, **kwargs):
+        with ArduinoAlvik._write_lock:
+            return method(*args, **kwargs)
+
+    return wrapper
+
+
+def reads_uart(method):
+    def wrapper(*args, **kwargs):
+        with ArduinoAlvik._read_lock:
+            return method(*args, **kwargs)
+
+    return wrapper
+
+
+class _AlvikRLock:
+    def __init__(self):
+        """Alvik re-entrant Lock implementation"""
+        self._lock = _thread.allocate_lock()
+        self._owner = None
+        self._count = 0
+
+    def acquire(self):
+        tid = _thread.get_ident()
+
+        if self._owner == tid:
+            self._count += 1
+            return True
+
+        self._lock.acquire()
+        self._owner = tid
+        self._count = 1
+        return True
+
+    def release(self):
+        tid = _thread.get_ident()
+
+        if self._owner != tid:
+            raise RuntimeError("Cannot release an unowned lock")
+
+        self._count -= 1
+        if self._count == 0:
+            self._owner = None
+            self._lock.release()
+
+    def locked(self):
+        return self._lock.locked()
+
+    def __enter__(self):
+        self.acquire()
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.release()
+
+
 class ArduinoAlvik:
     _update_thread_running = False
     _update_thread_id = None
     _events_thread_running = False
     _events_thread_id = None
 
+    _write_lock = _AlvikRLock()
+    _read_lock = _AlvikRLock()
+
     def __new__(cls):
         if not hasattr(cls, '_instance'):
             cls._instance = super(ArduinoAlvik, cls).__new__(cls)
@@ -119,7 +179,8 @@ def _print_battery_status(percentage: float, is_charging) -> None:
         word = marks_str + f" {percentage}% {charging_str} \t"
         print(word, end='')
 
-    def _lenghty_op(self, iterations=10000000) -> int:
+    @staticmethod
+    def _lengthy_op(self, iterations=10000000) -> int:
         result = 0
         for i in range(1, iterations):
             result += i * i
@@ -134,7 +195,7 @@ def _idle(self, delay_=1, check_on_thread=False, blocking=False) -> None:
         self.i2c.set_single_thread(True)
 
         if blocking:
-            self._lenghty_op(50000)
+            self._lengthy_op(50000)
         else:
             sleep_ms(500)
         led_val = 0
@@ -157,7 +218,7 @@ def _idle(self, delay_=1, check_on_thread=False, blocking=False) -> None:
                 self._battery_perc = abs(soc_perc)
                 self._print_battery_status(round(soc_perc), self._battery_is_charging)
                 if blocking:
-                    self._lenghty_op(10000)
+                    self._lengthy_op(10000)
                 else:
                     sleep_ms(delay_)
                 if soc_perc > 97:
@@ -169,13 +230,13 @@ def _idle(self, delay_=1, check_on_thread=False, blocking=False) -> None:
                     led_val = (led_val + 1) % 2
             self.i2c.set_single_thread(False)
             if self.is_on():
-                print("********** Alvik is on **********")
+                print("\n********** Alvik is on **********")
         except KeyboardInterrupt:
             self.stop()
             sys.exit()
         except Exception as e:
             pass
-            print(f'Unable to read SOC: {e}')
+            print(f'\nUnable to read SOC: {e}')
         finally:
             LEDR.value(1)
             LEDG.value(1)
@@ -232,7 +293,7 @@ def begin(self) -> int:
         self.set_behaviour(2)
         self._set_color_reference()
         if self._has_events_registered():
-            print('Starting events thread')
+            print('\n********** Starting events thread **********\n')
             self._start_events_thread()
         self.set_servo_positions(90, 90)
         return 0
@@ -279,6 +340,7 @@ def _wait_for_fw_check(self, timeout=5) -> bool:
             return False
 
     @staticmethod
+    @reads_uart
     def _flush_uart():
         """
         Empties the UART buffer
@@ -313,6 +375,7 @@ def _wait_for_target(self, idle_time):
                 # print(self._last_ack)
                 sleep_ms(100)
 
+    @writes_uart
     def is_target_reached(self) -> bool:
         """
         Returns True if robot has sent an M or R acknowledgment.
@@ -330,6 +393,7 @@ def is_target_reached(self) -> bool:
             return True
         return False
 
+    @writes_uart
     def set_behaviour(self, behaviour: int):
         """
         Sets the behaviour of Alvik
@@ -339,6 +403,7 @@ def set_behaviour(self, behaviour: int):
         self._packeter.packetC1B(ord('B'), behaviour & 0xFF)
         uart.write(self._packeter.msg[0:self._packeter.msg_size])
 
+    @writes_uart
     def rotate(self, angle: float, unit: str = 'deg', blocking: bool = True):
         """
         Rotates the robot by given angle
@@ -355,6 +420,7 @@ def rotate(self, angle: float, unit: str = 'deg', blocking: bool = True):
         if blocking:
             self._wait_for_target(idle_time=(angle / MOTOR_CONTROL_DEG_S))
 
+    @writes_uart
     def move(self, distance: float, unit: str = 'cm', blocking: bool = True):
         """
         Moves the robot by given distance
@@ -408,6 +474,7 @@ def get_wheels_speed(self, unit: str = 'rpm') -> (float | None, float | None):
         """
         return self.left_wheel.get_speed(unit), self.right_wheel.get_speed(unit)
 
+    @writes_uart
     def set_wheels_speed(self, left_speed: float, right_speed: float, unit: str = 'rpm'):
         """
         Sets left/right motor speed
@@ -427,6 +494,7 @@ def set_wheels_speed(self, left_speed: float, right_speed: float, unit: str = 'r
         self._packeter.packetC2F(ord('J'), left_speed, right_speed)
         uart.write(self._packeter.msg[0:self._packeter.msg_size])
 
+    @writes_uart
     def set_wheels_position(self, left_angle: float, right_angle: float, unit: str = 'deg', blocking: bool = True):
         """
         Sets left/right motor angle
@@ -490,6 +558,7 @@ def get_line_sensors(self) -> (int | None, int | None, int | None):
 
         return self._left_line, self._center_line, self._right_line
 
+    @writes_uart
     def drive(self, linear_velocity: float, angular_velocity: float, linear_unit: str = 'cm/s',
               angular_unit: str = 'deg/s'):
         """
@@ -530,6 +599,7 @@ def get_drive_speed(self, linear_unit: str = 'cm/s', angular_unit: str = 'deg/s'
 
         return convert_speed(self._linear_velocity, 'mm/s', linear_unit), angular_velocity
 
+    @writes_uart
     def reset_pose(self, x: float, y: float, theta: float, distance_unit: str = 'cm', angle_unit: str = 'deg'):
         """
         Resets the robot pose
@@ -559,6 +629,7 @@ def get_pose(self, distance_unit: str = 'cm', angle_unit: str = 'deg') \
                 convert_distance(self._y, 'mm', distance_unit),
                 convert_angle(self._theta, 'deg', angle_unit))
 
+    @writes_uart
     def set_servo_positions(self, a_position: int, b_position: int):
         """
         Sets A/B servomotor angle
@@ -586,10 +657,16 @@ def get_ack(self) -> str:
         """
         return self._last_ack
 
-    # def send_ack(self):
-    #     self._packeter.packetC1B(ord('X'), ACK_)
-    #     uart.write(self._packeter.msg[0:self._packeter.msg_size])
+    @writes_uart
+    def send_ack(self, ack: str = 'K'):
+        """
+        Sends an ack message on UART
+        :return:
+        """
+        self._packeter.packetC1B(ord('X'), ord(ack))
+        uart.write(self._packeter.msg[0:self._packeter.msg_size])
 
+    @writes_uart
     def _set_leds(self, led_state: int):
         """
         Sets the LEDs state
@@ -651,6 +728,7 @@ def _update(self, delay_=1):
             self._read_message()
             sleep_ms(delay_)
 
+    @reads_uart
     def _read_message(self) -> None:
         """
         Read a message from the uC
@@ -1539,15 +1617,15 @@ def writeto_mem(self, addr, memaddr, buf, addrsize=8) -> None:
             return i2c.writeto_mem(addr, memaddr, buf, addrsize=addrsize)
 
 
-
 class _ArduinoAlvikServo:
 
     def __init__(self, packeter: ucPack, label: str, servo_id: int, position: list[int | None]):
         self._packeter = packeter
         self._label = label
         self._id = servo_id
         self._position = position
-
+    
+    @writes_uart
     def set_position(self, position):
         """
         Sets the position of the servo
@@ -1576,7 +1654,8 @@ def __init__(self, packeter: ucPack, label: int, wheel_diameter_mm: float = WHEE
         self._speed = None
         self._position = None
         self._alvik = alvik
-
+    
+    @writes_uart
     def reset(self, initial_position: float = 0.0, unit: str = 'deg'):
         """
         Resets the wheel reference position
@@ -1588,6 +1667,7 @@ def reset(self, initial_position: float = 0.0, unit: str = 'deg'):
         self._packeter.packetC2B1F(ord('W'), self._label & 0xFF, ord('Z'), initial_position)
         uart.write(self._packeter.msg[0:self._packeter.msg_size])
 
+    @writes_uart
     def set_pid_gains(self, kp: float = MOTOR_KP_DEFAULT, ki: float = MOTOR_KI_DEFAULT, kd: float = MOTOR_KD_DEFAULT):
         """
         Set PID gains for Alvik wheels
@@ -1607,6 +1687,7 @@ def stop(self):
         """
         self.set_speed(0)
 
+    @writes_uart
     def set_speed(self, velocity: float, unit: str = 'rpm'):
         """
         Sets the motor speed
@@ -1643,6 +1724,7 @@ def get_position(self, unit: str = 'deg') -> float | None:
         """
         return convert_angle(self._position, 'deg', unit)
 
+    @writes_uart
     def set_position(self, position: float, unit: str = 'deg', blocking: bool = True):
         """
         Sets left/right motor speed
@@ -1673,6 +1755,7 @@ def __init__(self, packeter: ucPack, label: str, led_state: list[int | None], rg
         self._rgb_mask = rgb_mask
         self._led_state = led_state
 
+    @writes_uart
     def set_color(self, red: bool, green: bool, blue: bool):
         """
         Sets the LED's r,g,b state

package.json

@@ -13,5 +13,5 @@
         ["github:arduino/ucPack-mpy", "0.1.7"],
         ["github:arduino/arduino-runtime-mpy", "0.4.0"]
     ],
-    "version": "1.1.2"
+    "version": "1.1.3"
 }