Catching context starting error to quit when it happens.

4 files changed, 76 insertions, 9 deletions

diff --git a/src/argaze/DataFeatures.py b/src/argaze/DataFeatures.py
index 72f1d26..fa9b52e 100644
--- a/src/argaze/DataFeatures.py
+++ b/src/argaze/DataFeatures.py
@@ -658,6 +658,15 @@ class PipelineStepLoadingFailed(Exception):
 	def __init__(self, message):
 		super().__init__(message)
 
+
+class PipelineStepEnterFailed(Exception):
+	"""
+	Exception raised when pipeline step object context fails to enter.
+	"""
+
+	def __init__(self, message):
+		super().__init__(message)
+
 @timestamp
 class TimestampedImage(numpy.ndarray):
 	"""Wrap numpy.array to timestamp image."""
@@ -753,7 +762,16 @@ def PipelineStepEnter(method):
 
 		PipelineStepObject.__enter__(self)
 
-		method(self)
+		try:
+
+			method(self)
+
+			self._starting_error = None
+
+		except Exception as e:
+
+			self._starting_error = e
+			logging.error('%s.__enter__: %s', get_class_path(self), e)
 
 		return self
 
@@ -976,11 +994,13 @@ class PipelineStepObject():
 	"""
 
 	__initialized = False
+	_starting_error = None
 
 	def __init__(self):
 		"""Initialize PipelineStepObject."""
 
 		if not self.__initialized:
+
 			logging.debug('%s.__init__', get_class_path(self))
 
 			# Init private attributes
@@ -1013,6 +1033,8 @@ class PipelineStepObject():
 		for observer in self.observers:
 			observer.__enter__()
 
+		# Context starting error is catched in @PipelineStepEnter decorator wrapper
+
 		return self
 
 	def __exit__(self, exception_type, exception_value, exception_traceback):
@@ -1033,8 +1055,7 @@ class PipelineStepObject():
 
 			if hasattr(self, key):
 
-				logging.debug('%s.update_attributes > update %s with %s value', get_class_path(self), key,
-							  type(value).__name__)
+				logging.debug('%s.update_attributes > update %s with %s value', get_class_path(self), key, type(value).__name__)
 
 				setattr(self, key, value)
 
@@ -1043,6 +1064,11 @@ class PipelineStepObject():
 				raise (AttributeError(f'{get_class_path(self)} has not {key} attribute.'))
 
 	@property
+	def starting_error(self) -> Exception:
+		"""Get pipeline step object's context stating error."""
+		return self._starting_error
+
+	@property
 	def name(self) -> str:
 		"""Get pipeline step object's name."""
 		return self.__name
diff --git a/src/argaze/__main__.py b/src/argaze/__main__.py
index 12d654c..df3d338 100644
--- a/src/argaze/__main__.py
+++ b/src/argaze/__main__.py
@@ -72,10 +72,14 @@ def load_context(args):
 	# Load context from JSON file
 	with load(args.context_file) as context:
 
+		if context.starting_error is not None:
+
+			exit( RuntimeError(f'Context fails to start: {context.starting_error}') )
+
 		# Loaded object must be a subclass of ArContext
 		if not issubclass(type(context), ArContext):
 
-			raise TypeError('Loaded object is not a subclass of ArContext')
+			exit( TypeError('Loaded object is not a subclass of ArContext') )
 
 		if args.verbose:
 
diff --git a/src/argaze/utils/UtilsFeatures.py b/src/argaze/utils/UtilsFeatures.py
index 695f372..ff2bee6 100644
--- a/src/argaze/utils/UtilsFeatures.py
+++ b/src/argaze/utils/UtilsFeatures.py
@@ -79,6 +79,22 @@ def import_from_test_package(module: str) -> types.ModuleType:
 
 	return TestModule
 
+def ping(host):
+	"""
+    Returns True if host (str) responds to a ping request.
+    Remember that a host may not respond to a ping (ICMP) request even if the host name is valid.
+    """
+	import platform
+	import subprocess
+
+	# Option for the number of packets as a function of
+	param = '-n' if platform.system().lower()=='windows' else '-c'
+
+	# Building the command. Ex: "ping -c 1 google.com"
+	command = ['ping', param, '1', host]
+
+	return subprocess.call(command) == 0
+
 class TimeProbe():
 	"""
 	Assess temporal performance.
diff --git a/src/argaze/utils/contexts/TobiiProGlasses2.py b/src/argaze/utils/contexts/TobiiProGlasses2.py
index 061813e..80487f4 100644
--- a/src/argaze/utils/contexts/TobiiProGlasses2.py
+++ b/src/argaze/utils/contexts/TobiiProGlasses2.py
@@ -43,6 +43,7 @@ except ImportError:
 	from urllib2 import urlopen, Request, HTTPError, URLError
 
 from argaze import ArFeatures, DataFeatures
+from argaze.utils import UtilsFeatures
 
 import numpy
 import cv2
@@ -360,6 +361,12 @@ class LiveStream(ArFeatures.LiveProcessingContext):
 
 		self.__parser = TobiiJsonDataParser()
 
+		self.__data_thread = None
+		self.__video_thread = None
+		self.__video_buffer_read_thread = None
+		self.__keep_alive_thread = None
+		self.__check_battery_thread = None
+
 	@property
 	def address(self) -> str:
 		"""Network address where to find the device."""
@@ -514,7 +521,12 @@ class LiveStream(ArFeatures.LiveProcessingContext):
 	@DataFeatures.PipelineStepEnter
 	def __enter__(self):
 
-		logging.info('Tobii Pro Glasses 2 connexion starts...')
+		logging.info(f'Tobii Pro Glasses 2 connexion starts: trying to reach {self.__address} host...')
+
+		# Check that host exists
+		if not UtilsFeatures.ping(self.__address):
+
+			raise DataFeatures.PipelineStepEnterFailed(f'Tobii Pro Glasses 2 connexion fails: {self.__address} host unreachable.')
 
 		# Update current configuration with configuration patch
 		logging.debug('> updating configuration')
@@ -598,16 +610,25 @@ class LiveStream(ArFeatures.LiveProcessingContext):
 		self._stop_event.set()
 
 		# Stop keeping connection alive
-		threading.Thread.join(self.__keep_alive_thread)
+		if self.__keep_alive_thread is not None:
+
+			threading.Thread.join(self.__keep_alive_thread)
 
 		# Stop data streaming
-		threading.Thread.join(self.__data_thread)
+		if self.__data_thread is not None:
+
+			threading.Thread.join(self.__data_thread)
 
 		# Stop video buffer reading
-		threading.Thread.join(self.__video_buffer_read_thread)
+		if self.__video_buffer_read_thread is not None:
+		
+			threading.Thread.join(self.__video_buffer_read_thread)
 
 		# Stop video streaming
-		threading.Thread.join(self.__video_thread)
+		if self.__video_thread is not None:
+
+			threading.Thread.join(self.__video_thread)
+
 
 	def __make_socket(self):
 		"""Create a socket to enable network communication."""