Fixup factories to support environment variables

.gitignore

@@ -16,4 +16,5 @@
 **_pb2*
 **.egg-info*
 **/dist/*
-build
+build
+__pycache__

car/src/car/control/gpio/factory.py

@@ -0,0 +1,22 @@
+from .mockvehicle import MockVehicle
+import os
+
+
+def get_vehicle(motor_pin=19, steering_pin=18):
+    ENV_CAR = None
+    try:
+        ENV_CAR = os.environ['CAR_VEHICLE']
+    except KeyError:
+        print('Failed to find CAR_VEHICLE environment variable. Using mock.')
+        return MockVehicle()
+    if ENV_CAR == "CAR_2D":
+        try:
+            from .vehicle import Vehicle
+            return Vehicle(motor_pin, steering_pin)
+        except ImportError:
+            print(
+                'Could not import CAR_2D vehicle. Have you installed the GPIOZERO package?')
+    elif ENV_CAR == "CAR_MOCK":
+        return MockVehicle(motor_pin, steering_pin)
+    else:
+        print('No valid vehicle found. Have you set the CAR_VEHICLE environment variable?')

car/src/car/control/gpio/mockvehicle.py

@@ -5,6 +5,7 @@ class MockVehicle:
     def __init__(self, motor_pin=19, servo_pin=18):
         self.motor_pin = motor_pin
         self.steering_pin = servo_pin
+        print('Using Mock Vehicle')
 
     @property
     def throttle(self):

car/src/car/control/gpio/vehicle.py

@@ -14,6 +14,7 @@ def _safely_set_servo_value(servo, value):
         return False
     return True
 
+
 def _is_pin_valid(pin):
     if isinstance(pin, int):
         if pin < 2 or pin > 21:
@@ -26,6 +27,8 @@ def _is_pin_valid(pin):
 
 # TODO: Allow a vector to be set to change the throttle/steering, for vehicles that don't use
 # two servos for controls (e.g. drone, dog)
+
+
 class Vehicle:
     def __init__(self, motor_pin=19, servo_pin=18):
         subprocess.call(['sudo', 'pigpiod'])
@@ -39,7 +42,8 @@ class Vehicle:
     def initialise_motor(self):
         self._motor_servo = Servo(
             self._motor_pin, pin_factory=Device.pin_factory)
-        self._steering_servo = Servo(self._steering_pin, pin_factory=Device.pin_factory)
+        self._steering_servo = Servo(
+            self._steering_pin, pin_factory=Device.pin_factory)
 
     @property
     def throttle(self):
@@ -73,11 +77,13 @@ class Vehicle:
 
     @steering_pin.setter
     def steering_pin(self, value):
-        self._steering_pin = value if _is_pin_valid(value) else self._steering_pin
+        self._steering_pin = value if _is_pin_valid(
+            value) else self._steering_pin
 
     def stop(self):
         self.throttle = 0
         self.steering = 0
 
     def change_with_vector(self, vector):
+        # TBD how this will work. Could just be (magnitude,angle) change
         pass

car/src/car/controller.py

@@ -7,7 +7,7 @@ import time
 import grpc
 
 import car.control.motorService_pb2_grpc as motorService_pb2_grpc
-from car.control.gpio.vehicle import Vehicle
+import car.control.gpio.factory as vehicle_factory
 from car.control.motor_servicer import MotorServicer
 from car.slam.slam_servicer import SlamServicer
 import car.slam.SlamController_pb2_grpc as SlamController_pb2_grpc
@@ -22,12 +22,14 @@ class CarServer():
 
     def start_server(self):
         server = grpc.server(futures.ThreadPoolExecutor(max_workers=8))
-        motorService_pb2_grpc.add_CarControlServicer_to_server(self.create_motor_servicer(), server)
+        motorService_pb2_grpc.add_CarControlServicer_to_server(
+            self.create_motor_servicer(), server)
         SlamController_pb2_grpc.add_SlamControlServicer_to_server(
             self.create_slam_servicer(), server)
         lidar_tracker_pb2_grpc.add_PersonTrackingServicer_to_server(
             self.create_lidar_servicer(), server)
-        # Disable tls for local testing.
+
+        # Disable tls for local testing for now.
         # server.add_secure_port('[::]:50051', self.create_credentials())
         server.add_insecure_port('[::]:50051')
         server.start()
@@ -44,7 +46,7 @@ class CarServer():
         return LidarServicer()
 
     def create_credentials(self):
-        # Relativise this stuff.
+        # Relativise this stuff. Should add to source directory.
         pvtKeyPath = '/home/pi/tls/device.key'
         pvtCertPath = '/home/pi/tls/device.crt'
 
@@ -55,8 +57,7 @@ class CarServer():
 
 
 if __name__ == '__main__':
-    vehicle = Vehicle()
-    server = CarServer(vehicle)
+    server = CarServer(vehicle_factory.get_vehicle())
 
     # Can't remember why I do this, is it even needed?
     service_thread = Thread(target=server.start_server)

car/src/car/slam/slam_servicer.py

@@ -1,5 +1,6 @@
 import car.slam.SlamController_pb2_grpc as grpc
 import car.slam.SlamController_pb2 as proto
+import car.empty_pb2 as empty
 import car.slam.slam_streamer as slam
 from multiprocessing import Process
 
@@ -21,11 +22,11 @@ class SlamServicer(grpc.SlamControlServicer):
             self.slam.map_meters = request.map_size_meters
             self.slam_thread = Process(target=self.slam.start)
             self.slam_thread.start()
-        return proto.Empty()
+        return empty.Empty()
 
     def stop_streaming(self, request, context):
         if self.slam_thread is not None:
             self.slam.stop_scanning()
             self.slam_thread.join()
             self.slam = None
-        return proto.Empty()
+        return empty.Empty()

car/src/car/tracking/devices/factory.py

@@ -1,18 +1,27 @@
-from car.tracking.devices.mock_lidar import MockLidar
-import car.tracking.lidar_loader as loader
+from .mock_lidar import MockLidar
+from .. import lidar_loader as loader
+import os
 
-# connection = "TEST"
-connection = '/dev/ttyUSB0'
+MOCK_DEVICE = "LIDAR_MOCK"
+RPLIDAR = "LIDAR_RPLIDAR"
 
-def get_lidar():
-    # Need a way to configure this, maybe with environment variables
-    if connection == 'TEST':
-        return MockLidar(loader.load_scans_bytes_file("tracking/out.pickle"))
-    else:
+
+def get_lidar(device=None, connection='/dev/ttyUSB0'):
+    actual_device = None
+    try:
+        actual_device = device if device is not None else os.environ["CAR_LIDAR"]
+    except KeyError:
+        print(
+            'No lidar device specified and the CAR_LIDAR environment variable is not set.')
+    if actual_device == MOCK_DEVICE:
+        return MockLidar(loader.load_scans_bytes_file("car/tracking/out.pickle"))
+    elif actual_device == RPLIDAR:
         try:
             from rplidar import RPLidar
             return RPLidar(connection)
         except ImportError:
-            print('Could not import RPLidar, using mock with testing data.')
-            return MockLidar(loader.load_scans_bytes_file("tracking/out.pickle"))
-
+            print('Could not import RPLidar. Have you downloaded rplidar?')
+    else:
+        print('No valid lidar device found. Please choose one of ' +
+              MOCK_DEVICE + ' or ' + RPLIDAR)
+    return None

car/src/car/tracking/lidar_loader.py

@@ -6,11 +6,11 @@ As such, it is useful for testing, to create real lidar
 data that can be reused later, without needing to connect the lidar.
 """
 
-from rplidar import RPLidar
 import pickle
 
 
 def get_scans(num_scans, device='/dev/ttyUSB0', measurements_per_scan=100):
+    from rplidar import RPLidar
     lidar = RPLidar(device)
     scans = lidar.iter_scans(measurements_per_scan)
     return [next(scans) for i in range(0, num_scans)]