Enabling Coach Documentation to be run even when environments are not installed (#326)

rl_coach/environments/carla_environment.py

@@ -17,7 +17,6 @@
 import random
 import sys
 from os import path, environ
-
 from rl_coach.logger import screen
 from rl_coach.filters.action.partial_discrete_action_space_map import PartialDiscreteActionSpaceMap
 from rl_coach.filters.observation.observation_rgb_to_y_filter import ObservationRGBToYFilter
@@ -27,7 +26,8 @@ try:
     if 'CARLA_ROOT' in environ:
         sys.path.append(path.join(environ.get('CARLA_ROOT'), 'PythonClient'))
     else:
-        screen.error("CARLA_ROOT was not defined. Please set it to point to the CARLA root directory and try again.")
+        screen.error("CARLA_ROOT was not defined. Please set it to point to the CARLA root directory and try again.", crash=False)
+
     from carla.client import CarlaClient
     from carla.settings import CarlaSettings
     from carla.tcp import TCPConnectionError
@@ -39,21 +39,20 @@ except ImportError:
     from rl_coach.logger import failed_imports
     failed_imports.append("CARLA")
 
-import logging
-import subprocess
-from rl_coach.environments.environment import Environment, EnvironmentParameters, LevelSelection
-from rl_coach.spaces import BoxActionSpace, ImageObservationSpace, StateSpace, \
-    VectorObservationSpace
-from rl_coach.utils import get_open_port, force_list
-from enum import Enum
 import os
 import signal
+import logging
+import subprocess
+import numpy as np
+from rl_coach.environments.environment import Environment, EnvironmentParameters, LevelSelection
+from rl_coach.spaces import BoxActionSpace, ImageObservationSpace, StateSpace, VectorObservationSpace
+from rl_coach.utils import get_open_port, force_list
+from enum import Enum
 from typing import List, Union
 from rl_coach.base_parameters import VisualizationParameters
 from rl_coach.filters.filter import InputFilter, NoOutputFilter
 from rl_coach.filters.observation.observation_rescale_to_size_filter import ObservationRescaleToSizeFilter
 from rl_coach.filters.observation.observation_stacking_filter import ObservationStackingFilter
-import numpy as np
 
 
 # enum of the available levels and their path
@@ -61,6 +60,7 @@ class CarlaLevel(Enum):
     TOWN1 = {"map_name": "Town01", "map_path": "/Game/Maps/Town01"}
     TOWN2 = {"map_name": "Town02", "map_path": "/Game/Maps/Town02"}
 
+
 key_map = {
     'BRAKE': (274,),  # down arrow
     'GAS': (273,),  # up arrow