Defining a new PipelineStep decorator to assess time execution and catch exceptions. Improving logging scope.

21 files changed, 237 insertions, 242 deletions

diff --git a/src/argaze/ArFeatures.py b/src/argaze/ArFeatures.py
index 281dec8..30044a7 100644
--- a/src/argaze/ArFeatures.py
+++ b/src/argaze/ArFeatures.py
@@ -130,6 +130,9 @@ class ArLayer(DataFeatures.SharedObject):
 		# Init current gaze movement
 		self.__gaze_movement = GazeFeatures.UnvalidGazeMovement()
 
+		# Init new analysis available state
+		self.__new_analysis_available = False
+
 		# Cast aoi scene to its effective dimension
 		if self.aoi_scene.dimension == 2:
 
@@ -293,7 +296,10 @@ class ArLayer(DataFeatures.SharedObject):
 
 			for logger_name, logger_data in new_loggers_value.items():
 
-				new_loggers[logger_name] = DataFeatures.TimeStampedDataLogger.from_dict(logger_data)
+				logger = DataFeatures.TimeStampedDataLogger.from_dict(logger_data)
+				logger.name = logger_name
+
+				new_loggers[logger_name] = logger
 
 		except KeyError:
 
@@ -346,6 +352,13 @@ class ArLayer(DataFeatures.SharedObject):
 
 		self.__parent = parent
 
+	@property
+	def new_analysis_available(self) -> bool:
+		"""Is there new aoi scan path analysis to check?"""
+
+		return self.__new_analysis_available
+
+	@DataFeatures.PipelineStep
 	def look(self, timestamp: int|float, gaze_movement: GazeFeatures.GazePosition = GazeFeatures.UnvalidGazePosition()) -> dict:
 		"""
 		Project timestamped gaze movement into layer.
@@ -355,123 +368,65 @@ class ArLayer(DataFeatures.SharedObject):
 
 		Parameters:
 			gaze_movement: gaze movement to project
-
-		Returns:
-			look_data: data dictionary
-
-		!!! note "look data dictionary"
-			- **gaze_movement**: incoming gaze movement
-			- **looked_aoi_name**: most likely looked aoi name
-			- **looked_aoi**: most likely looked aoi shape
-			- **aoi_scan_path_analysis**: aoi scan path analysis at each new scan step if aoi_scan_path is instanciated
-			- **exception**: error catched during gaze movement processing
 		"""
 
 		# Lock layer exploitation
 		self.acquire()
 
-		# Store look execution start date
-		look_start = time.perf_counter()
+		# Gather look data
+		look_data = locals()
 
 		# Update current gaze movement
 		self.__gaze_movement = gaze_movement
 
-		# Init looked aoi
-		looked_aoi_name, looked_aoi = (None, None)
-
-		# Init aoi scan path analysis report
-		aoi_scan_path_analysis = {}
-
-		# Assess pipeline execution times
-		execution_times = {
-			'aoi_matcher': None,
-			'aoi_scan_path_analyzers': {}
-		}
-
-		# Catch any error
-		exception = None
-
-		try:
-
-			if self.aoi_matcher is not None:
-
-				# Store aoi matching start date
-				matching_start = time.perf_counter()
-
-				# Update looked aoi thanks to aoi matcher
-				# Note: don't filter valid/unvalid and finished/unfinished fixation/saccade as we don't know how the aoi matcher works internally
-				looked_aoi_name, looked_aoi = self.aoi_matcher.match(self.aoi_scene, gaze_movement)
+		# No new analysis available by default
+		self.__new_analysis_available = False
 
-				# Assess aoi matching time in ms
-				execution_times['aoi_matcher'] = (time.perf_counter() - matching_start) * 1e3
+		# Init looked aoi name
+		looked_aoi_name = None
 
-			# Valid and finished gaze movement has been identified
-			if gaze_movement.valid and gaze_movement.finished:
+		if self.aoi_matcher is not None:
 
-				if GazeFeatures.is_fixation(gaze_movement):
+			# Update looked aoi thanks to aoi matcher
+			# Note: don't filter valid/unvalid and finished/unfinished fixation/saccade as we don't know how the aoi matcher works internally
+			looked_aoi_name, _ , match_time, match_exception = self.aoi_matcher.match(self.aoi_scene, gaze_movement)
 
-					# Append fixation to aoi scan path
-					if self.aoi_scan_path is not None and looked_aoi_name is not None:
+		# Valid and finished gaze movement has been identified
+		if gaze_movement.valid and gaze_movement.finished:
 
-						aoi_scan_step = self.aoi_scan_path.append_fixation(timestamp, gaze_movement, looked_aoi_name)
+			if GazeFeatures.is_fixation(gaze_movement):
 
-						# Is there a new step?
-						if aoi_scan_step is not None and len(self.aoi_scan_path) > 1:
+				# Append fixation to aoi scan path
+				if self.aoi_scan_path is not None and looked_aoi_name is not None:
 
-							for aoi_scan_path_analyzer_module_path, aoi_scan_path_analyzer in self.aoi_scan_path_analyzers.items():
+					aoi_scan_step = self.aoi_scan_path.append_fixation(timestamp, gaze_movement, looked_aoi_name)
 
-								# Store aoi scan path analysis start date
-								aoi_scan_path_analysis_start = time.perf_counter()
+					# Is there a new step?
+					if aoi_scan_step is not None and len(self.aoi_scan_path) > 1:
 
-								# Analyze aoi scan path
-								aoi_scan_path_analyzer.analyze(self.aoi_scan_path)
+						for aoi_scan_path_analyzer_module_path, aoi_scan_path_analyzer in self.aoi_scan_path_analyzers.items():
 
-								# Assess aoi scan path analysis time in ms
-								execution_times['aoi_scan_path_analyzers'][aoi_scan_path_analyzer_module_path] = (time.perf_counter() - aoi_scan_path_analysis_start) * 1e3
+							# Analyze aoi scan path
+							analyze_time, analyze_exception = aoi_scan_path_analyzer.analyze(self.aoi_scan_path)
 
-								# Store analysis
-								aoi_scan_path_analysis[aoi_scan_path_analyzer_module_path] = aoi_scan_path_analyzer.analysis
+						# Update new analysis available state
+						self.__new_analysis_available = True
 
-				elif GazeFeatures.is_saccade(gaze_movement):
+			elif GazeFeatures.is_saccade(gaze_movement):
 
-					# Append saccade to aoi scan path
-					if self.aoi_scan_path is not None:
+				# Append saccade to aoi scan path
+				if self.aoi_scan_path is not None:
 
-						self.aoi_scan_path.append_saccade(timestamp, gaze_movement)
-
-		except Exception as e:
-
-			print('Warning: the following error occurs in ArLayer.look method:', e)
-
-			looked_aoi_name = None
-			looked_aoi = None
-			aoi_scan_path_analysis = {}
-			exception = e
-
-		# Assess total execution time in ms
-		execution_times['total'] = (time.perf_counter() - look_start) * 1e3
-
-		# Edit look data dictionary
-		look_data = DataFeatures.DataDictionary({
-			"gaze_movement": gaze_movement,
-			"looked_aoi_name": looked_aoi_name,
-			"looked_aoi": looked_aoi,
-			"aoi_scan_path_analysis": DataFeatures.DataDictionary(aoi_scan_path_analysis),
-			"execution_times": DataFeatures.DataDictionary(execution_times),
-			"exception": exception
-		})
+					self.aoi_scan_path.append_saccade(timestamp, gaze_movement)
 
 		# Log look data
 		for logger_name, logger in self.loggers.items():
 
-			logger.emit(timestamp, DataFeatures.DataDictionary(look_data))
+			logger.emit(look_data)
 		
 		# Unlock layer exploitation
 		self.release()
 
-		# Return look data dictionary
-		return look_data
-
 	def draw(self, image: numpy.array, draw_aoi_scene: dict = None, draw_aoi_matching: dict = None):
 		"""
 		Draw into image.
@@ -573,7 +528,13 @@ class ArFrame(DataFeatures.SharedObject):
 			layer.parent = self
 
 		# Init current gaze position
-		self.__gaze_position = GazeFeatures.UnvalidGazePosition()
+		self.__calibrated_gaze_position = GazeFeatures.UnvalidGazePosition()
+
+		# Init current gaze movement
+		self.__identified_gaze_movement = GazeFeatures.UnvalidGazeMovement()
+
+		# Init new analysis available state
+		self.__new_analysis_available = False
 
 	@classmethod
 	def from_dict(self, frame_data: dict, working_directory: str = None) -> ArFrameType:
@@ -771,7 +732,10 @@ class ArFrame(DataFeatures.SharedObject):
 
 			for logger_name, logger_data in new_loggers_value.items():
 
-				new_loggers[logger_name] = DataFeatures.TimeStampedDataLogger.from_dict(logger_data)
+				logger = DataFeatures.TimeStampedDataLogger.from_dict(logger_data)
+				logger.name = logger_name
+
+				new_loggers[logger_name] = logger
 
 		except KeyError:
 
@@ -829,7 +793,26 @@ class ArFrame(DataFeatures.SharedObject):
 
 		self.__parent = parent
 
-	def look(self, timestamp: int|float, gaze_position: GazeFeatures.GazePosition = GazeFeatures.UnvalidGazePosition()) -> DataFeatures.DataDictionary:
+	@property
+	def gaze_position(self) -> object:
+		"""Get current calibrated gaze position"""
+
+		return self.__calibrated_gaze_position
+
+	@property
+	def gaze_movement(self) -> object:
+		"""Get current identified gaze movement"""
+		
+		return self.__identified_gaze_movement
+
+	@property
+	def new_analysis_available(self) -> bool:
+		"""Is there new scan path analysis to check?"""
+
+		return self.__new_analysis_available
+
+	@DataFeatures.PipelineStep
+	def look(self, timestamp: int|float, gaze_position: GazeFeatures.GazePosition = GazeFeatures.UnvalidGazePosition()):
 		"""
 		Project gaze position into frame.
 
@@ -839,162 +822,92 @@ class ArFrame(DataFeatures.SharedObject):
 		Parameters:
 			timestamp: any number used to know when the given gaze position occurs
 			gaze_position: gaze position to project
-
-		Returns:
-			look_data: data dictionary
-
-		!!! note "look data dictionary"
-			- **gaze_position**: calibrated gaze position if gaze_position_calibrator is instanciated else, given gaze position.
-			- **gaze_movement**: identified gaze movement from incoming consecutive timestamped gaze positions if gaze_movement_identifier is instanciated. Current gaze movement if filter_in_progress_identification is False.
-			- **scan_path_analysis**: scan path analysis at each new scan step if scan_path is instanciated.
-			- **execution_times**: all pipeline steps execution times.
-			- **exception**: error catched during gaze position processing.
-			- **layers**: data dictionary with each layer's look data.
 		"""
 
 		# Lock frame exploitation
 		self.acquire()
 
-		# Store look execution start date
-		look_start = time.perf_counter()
-
-		# No gaze movement identified by default
-		identified_gaze_movement = GazeFeatures.UnvalidGazeMovement()
-
-		# Init scan path analysis report
-		scan_step_analysis = {}
-
-		# Assess pipeline execution times
-		execution_times = {
-			'gaze_movement_identifier': None,
-			'scan_path_analyzers': DataFeatures.DataDictionary({}),
-			'heatmap': None
-		}
-
-		# Catch any error
-		exception = None
-
-		# Init layers look data report
-		layers_look_data = {}
-
-		try:
-
-			# Apply gaze position calibration
-			if self.gaze_position_calibrator is not None:
+		# Store look arguments
+		look_data = locals()
 
-				self.__gaze_position = self.gaze_position_calibrator.apply(gaze_position)
+		# No new analysis by default
+		self.__new_analysis_available = False
 
-			# Or update gaze position at least
-			else:
-
-				self.__gaze_position = gaze_position
-
-			# Identify gaze movement
-			if self.gaze_movement_identifier is not None:
-
-				# Store movement identification start date
-				identification_start = time.perf_counter()
-
-				# Identify finished gaze movement
-				identified_gaze_movement = self.gaze_movement_identifier.identify(timestamp, self.__gaze_position)
-
-				# Assess movement identification time in ms
-				execution_times['gaze_movement_identifier'] = (time.perf_counter() - identification_start) * 1e3
-
-			# Valid and finished gaze movement has been identified
-			if identified_gaze_movement.valid and identified_gaze_movement.finished:
-
-				if GazeFeatures.is_fixation(identified_gaze_movement):
-
-					# Append fixation to scan path
-					if self.scan_path is not None:
+		# No gaze movement identified by default
+		self.__identified_gaze_movement = GazeFeatures.UnvalidGazeMovement()
 
-						self.scan_path.append_fixation(timestamp, identified_gaze_movement)
+		# Apply gaze position calibration
+		if self.gaze_position_calibrator is not None:
 
-				elif GazeFeatures.is_saccade(identified_gaze_movement):
+			self.__calibrated_gaze_position = self.gaze_position_calibrator.apply(gaze_position)
 
-					# Append saccade to scan path
-					if self.scan_path is not None:
-						
-						scan_step = self.scan_path.append_saccade(timestamp, identified_gaze_movement)
+		# Or update gaze position at least
+		else:
 
-						# Is there a new step?
-						if scan_step and len(self.scan_path) > 1:
+			self.__calibrated_gaze_position = gaze_position
 
-							for scan_path_analyzer_module_path, scan_path_analyzer in self.scan_path_analyzers.items():
+		# Identify gaze movement
+		if self.gaze_movement_identifier is not None:
 
-								# Store scan step analysis start date
-								scan_step_analysis_start = time.perf_counter()
+			# Identify finished gaze movement
+			self.__identified_gaze_movement, identify_time, identify_exception = self.gaze_movement_identifier.identify(timestamp, self.__calibrated_gaze_position)
 
-								# Analyze aoi scan path
-								scan_path_analyzer.analyze(self.scan_path)
+		# Valid and finished gaze movement has been identified
+		if self.__identified_gaze_movement.valid and self.__identified_gaze_movement.finished:
 
-								# Assess scan path analysis time in ms
-								execution_times['scan_path_analyzers'][scan_path_analyzer_module_path] = (time.perf_counter() - scan_step_analysis_start) * 1e3
+			if GazeFeatures.is_fixation(self.__identified_gaze_movement):
 
-								# Store analysis
-								scan_step_analysis[scan_path_analyzer_module_path] = scan_path_analyzer.analysis
+				# Append fixation to scan path
+				if self.scan_path is not None:
 
-			# No valid finished gaze movement: optionnaly stop in progress identification filtering
-			elif self.gaze_movement_identifier is not None and not self.filter_in_progress_identification:
+					self.scan_path.append_fixation(timestamp, self.__identified_gaze_movement)
 
-				identified_gaze_movement = self.gaze_movement_identifier.current_gaze_movement
+			elif GazeFeatures.is_saccade(self.__identified_gaze_movement):
 
-			# Update heatmap
-			if self.heatmap is not None:
+				# Append saccade to scan path
+				if self.scan_path is not None:
+					
+					scan_step = self.scan_path.append_saccade(timestamp, self.__identified_gaze_movement)
 
-				# Store heatmap start date
-				heatmap_start = time.perf_counter()
+					# Is there a new step?
+					if scan_step and len(self.scan_path) > 1:
 
-				# Scale gaze position value
-				scale = numpy.array([self.heatmap.size[0] / self.size[0], self.heatmap.size[1] / self.size[1]])
+						for scan_path_analyzer_module_path, scan_path_analyzer in self.scan_path_analyzers.items():
 
-				# Update heatmap image
-				self.heatmap.update(self.__gaze_position.value * scale)
+							# Analyze aoi scan path
+							analyze_time, analyze_exception = scan_path_analyzer.analyze(self.scan_path)
 
-				# Assess heatmap time in ms
-				execution_times['heatmap'] = (time.perf_counter() - heatmap_start) * 1e3
+						# Update new analysis available state
+						self.__new_analysis_available = True
 
-			# Look layers with valid identified gaze movement
-			# Note: don't filter valid/unvalid finished/unfished gaze movement to allow layers to reset internally
-			for layer_name, layer in self.layers.items():
+		# No valid finished gaze movement: optionnaly stop in progress identification filtering
+		elif self.gaze_movement_identifier is not None and not self.filter_in_progress_identification:
 
-				layers_look_data[layer_name] = layer.look(timestamp, identified_gaze_movement)
+			self.__identified_gaze_movement = self.gaze_movement_identifier.current_gaze_movement
 
-		except Exception as e:
+		# Update heatmap
+		if self.heatmap is not None:
 
-			print('Warning: the following error occurs in ArFrame.look method:', e)
+			# Scale gaze position value
+			scale = numpy.array([self.heatmap.size[0] / self.size[0], self.heatmap.size[1] / self.size[1]])
 
-			self.__gaze_position = GazeFeatures.UnvalidGazePosition()
-			identified_gaze_movement = GazeFeatures.UnvalidGazeMovement()
-			scan_step_analysis = {}
-			exception = e
-			layers_look_data = {}
+			# Update heatmap image
+			update_time, update_exception = self.heatmap.update(self.__calibrated_gaze_position.value * scale)
 
-		# Assess total execution time in ms
-		execution_times['total'] = (time.perf_counter() - look_start) * 1e3
+		# Look layers with valid identified gaze movement
+		# Note: don't filter valid/unvalid finished/unfished gaze movement to allow layers to reset internally
+		for layer_name, layer in self.layers.items():
 
-		# Edit look data dictionary
-		look_data = DataFeatures.DataDictionary({
-			"gaze_position": self.__gaze_position, 
-			"gaze_movement": identified_gaze_movement, 
-			"scan_path_analysis": DataFeatures.DataDictionary(scan_step_analysis), 
-			"execution_times": DataFeatures.DataDictionary(execution_times),
-			"exception": exception, 
-			"layers": DataFeatures.DataDictionary(layers_look_data)
-		})
+			look_time, look_exception = layer.look(timestamp, self.__identified_gaze_movement)
 
 		# Log look data
 		for logger_name, logger in self.loggers.items():
 
-			logger.emit(timestamp, look_data)
+			logger.emit(look_data)
 
 		# Unlock frame exploitation
 		self.release()
 
-		# Return look data
-		return look_data
-
 	def __image(self, background_weight: float = None, heatmap_weight: float = None, draw_gaze_position_calibrator: dict = None, draw_scan_path: dict = None, draw_layers: dict = None, draw_gaze_positions: dict = None, draw_fixations: dict = None, draw_saccades: dict = None) -> numpy.array:
 		"""
 		Get background image with overlaid visualisations.
@@ -1065,7 +978,7 @@ class ArFrame(DataFeatures.SharedObject):
 		# Draw current gaze position if required
 		if draw_gaze_positions is not None:
 
-			self.__gaze_position.draw(image, **draw_gaze_positions)
+			self.__calibrated_gaze_position.draw(image, **draw_gaze_positions)
 
 		# Unlock frame exploitation
 		self.release()
diff --git a/src/argaze/AreaOfInterest/AOIFeatures.py b/src/argaze/AreaOfInterest/AOIFeatures.py
index 9f9f4ad..e20717c 100644
--- a/src/argaze/AreaOfInterest/AOIFeatures.py
+++ b/src/argaze/AreaOfInterest/AOIFeatures.py
@@ -599,6 +599,7 @@ class Heatmap():
         self.__point_spread_buffer = []
         self.__point_spread_buffer_size = self.buffer
 
+    @DataFeatures.PipelineStep
     def update(self, point: tuple):
         """Update heatmap image."""
 
diff --git a/src/argaze/DataFeatures.py b/src/argaze/DataFeatures.py
index 3e372fb..12e7bff 100644
--- a/src/argaze/DataFeatures.py
+++ b/src/argaze/DataFeatures.py
@@ -10,13 +10,14 @@ __license__ = "BSD"
 from typing import TypeVar, Tuple, Any
 from dataclasses import dataclass, field
 import importlib
-from inspect import getmembers
+from inspect import getmembers, getmodule
 import collections
 import json
 import ast
 import bisect
 import threading
 import math
+import time
 
 import pandas
 import numpy
@@ -428,6 +429,51 @@ class DataDictionary(dict):
     __setattr__ = dict.__setitem__
     __delattr__ = dict.__delitem__
 
+def PipelineStep(method):
+    """Define a decorator to define a method as a pipeline step."""
+
+    def handler(*args, **kw) -> Tuple[Any, float, Exception]:
+        """Handle pipeline step
+        
+        Returns:
+            method_returns: what the handled method returns
+            execution_time: measure of method time execution in millisecond.
+            exception: any error catched during method execution.
+        """
+
+        # Initialize execution time assessment
+        start = time.perf_counter()
+        
+        try:
+
+            result = method(*args, **kw)
+            exception = None
+
+        except Exception as e:
+
+            result = None
+            exception = e
+        
+        # Measure execution time
+        execution_time = (time.perf_counter() - start) * 1e3
+
+        # Edit result tuple
+        if type(result) is tuple:
+
+            result = result + (execution_time, exception)
+
+        elif result is not None:
+
+            result = result, execution_time, exception
+
+        else:
+
+            result = execution_time, exception
+
+        return result
+
+    return handler
+
 # Import libraries that can be used in selector or formatter codes
 from argaze import GazeFeatures
 
@@ -438,6 +484,9 @@ TimeStampedDataLoggerType = TypeVar('TimeStampedDataLogger', bound="TimeStampedD
 class TimeStampedDataLogger():
     """Abstract class to define what should provide a timestamped data logger."""
 
+    name: str = field(default='')
+    """Name of logger."""
+
     selector: str = field(default='True')
     """Code evaluated to handle log under a condition. Default 'True' string means that all incoming data will be accepted."""
 
@@ -449,8 +498,7 @@ class TimeStampedDataLogger():
         """Load timestamped data logger from dictionary.
 
         Parameters:
-            logger_module_path: class name to load
-            logger_parameters: attributes to load
+            logger_data: dict to load
         """
 
         logger_module_path, logger_parameters = logger_data.popitem()
@@ -462,16 +510,20 @@ class TimeStampedDataLogger():
         logger_module = importlib.import_module(logger_module_path)
         return logger_module.TimeStampedDataLogger(**logger_parameters)
 
-    def emit(self, timestamp: TimeStampType, data: DataDictionary) -> Any:
-        """Apply selector code to decide if data have to be logged, then apply formatter code before to call specific logger handle method."""
+    def emit(self, context: dict) -> Any:
+        """Apply selector code to decide if context have to be logged, then apply formatter code before to call specific logger handle method."""
+
+        try:
+
+            if eval(self.selector, globals(), context):
 
-        data['timestamp'] = timestamp
+                self.handle(eval(self.formatter, globals(), context))
 
-        if eval(self.selector, globals(), data):
+        except Exception as e:
 
-            self.handle(eval(self.formatter, globals(), data))
+            print(f'Warning: the following error occurs in TimeStampedDataLogger.emit method ({self.name}):', e)
 
-    def handle(self, formatted_log: any):
-        """Handle formatted log emission to destination."""
+    def handle(self, log: any):
+        """Handle log emission to destination."""
 
         raise NotImplementedError('handle() method not implemented')
diff --git a/src/argaze/DataLog/FileWriter.py b/src/argaze/DataLog/FileWriter.py
index 9b9fc5f..388ec44 100644
--- a/src/argaze/DataLog/FileWriter.py
+++ b/src/argaze/DataLog/FileWriter.py
@@ -48,13 +48,13 @@ class TimeStampedDataLogger(DataFeatures.TimeStampedDataLogger):
 
         self._file.close()
 
-    def handle(self, formatted_log: any):
+    def handle(self, log: any):
         """Write log as a new line into file. List or tuple are converted into strings separated by separator char."""
 
         # Format list or tuple element into quoted strings
-        if not isinstance(formatted_log, str):
+        if not isinstance(log, str):
 
-            formatted_log = self.separator.join(f'\"{d}\"' for d in formatted_log)
+            log = self.separator.join(f'\"{d}\"' for d in log)
 
         # Write into file
-        print(formatted_log, file=self._file, flush=True)
\ No newline at end of file
+        print(log, file=self._file, flush=True)
\ No newline at end of file
diff --git a/src/argaze/GazeAnalysis/Basic.py b/src/argaze/GazeAnalysis/Basic.py
index a11991f..4631483 100644
--- a/src/argaze/GazeAnalysis/Basic.py
+++ b/src/argaze/GazeAnalysis/Basic.py
@@ -10,7 +10,7 @@ __license__ = "BSD"
 
 from dataclasses import dataclass
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import numpy
 
@@ -26,6 +26,7 @@ class ScanPathAnalyzer(GazeFeatures.ScanPathAnalyzer):
         self.__steps_number = 0
         self.__step_fixation_durations_average = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, scan_path: GazeFeatures.ScanPathType):
 
         self.__path_duration = scan_path.duration
@@ -34,6 +35,9 @@ class ScanPathAnalyzer(GazeFeatures.ScanPathAnalyzer):
 
         sum_fixation_durations = 0
 
+        # DEBUG
+        a = 1 / 0
+
         for scan_step in scan_path:
 
             sum_fixation_durations += scan_step.fixation_duration
@@ -70,6 +74,7 @@ class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
         self.__steps_number = 0
         self.__step_fixation_durations_average = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: GazeFeatures.ScanPathType):
 
         self.__path_duration = aoi_scan_path.duration
diff --git a/src/argaze/GazeAnalysis/DeviationCircleCoverage.py b/src/argaze/GazeAnalysis/DeviationCircleCoverage.py
index fde9543..c86ebed 100644
--- a/src/argaze/GazeAnalysis/DeviationCircleCoverage.py
+++ b/src/argaze/GazeAnalysis/DeviationCircleCoverage.py
@@ -12,7 +12,7 @@ from typing import TypeVar, Tuple
 from dataclasses import dataclass, field
 import math
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 from argaze.AreaOfInterest import AOIFeatures
 
 import numpy
@@ -37,6 +37,7 @@ class AOIMatcher(GazeFeatures.AOIMatcher):
         self.__matched_gaze_movement = None
         self.__matched_region = None
 
+    @DataFeatures.PipelineStep
     def match(self, aoi_scene, gaze_movement) -> Tuple[str, AOIFeatures.AreaOfInterest]:
         """Returns AOI with the maximal fixation's deviation circle coverage if above coverage threshold."""
 
diff --git a/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py b/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py
index 36dfabf..f3ee608 100644
--- a/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py
+++ b/src/argaze/GazeAnalysis/DispersionThresholdIdentification.py
@@ -12,7 +12,7 @@ from typing import TypeVar, Tuple
 from dataclasses import dataclass, field
 import math
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import numpy
 import cv2
@@ -142,6 +142,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         self.__fixation_positions = GazeFeatures.TimeStampedGazePositions()
         self.__saccade_positions = GazeFeatures.TimeStampedGazePositions()
 
+    @DataFeatures.PipelineStep
     def identify(self, ts, gaze_position, terminate=False) -> GazeMovementType:
 
         # Ignore non valid gaze position
diff --git a/src/argaze/GazeAnalysis/Entropy.py b/src/argaze/GazeAnalysis/Entropy.py
index 631a8ea..a391092 100644
--- a/src/argaze/GazeAnalysis/Entropy.py
+++ b/src/argaze/GazeAnalysis/Entropy.py
@@ -11,7 +11,7 @@ __license__ = "BSD"
 from typing import Tuple
 from dataclasses import dataclass, field
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 from argaze.GazeAnalysis import TransitionMatrix
 
 import pandas
@@ -37,6 +37,7 @@ class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
         self.__stationary_entropy = -1
         self.__transition_entropy = -1
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: GazeFeatures.AOIScanPathType):
 
         assert(len(aoi_scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/ExploreExploitRatio.py b/src/argaze/GazeAnalysis/ExploreExploitRatio.py
index b66076b..d4c0b6c 100644
--- a/src/argaze/GazeAnalysis/ExploreExploitRatio.py
+++ b/src/argaze/GazeAnalysis/ExploreExploitRatio.py
@@ -10,7 +10,7 @@ __license__ = "BSD"
 
 from dataclasses import dataclass, field
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import numpy
 
@@ -33,6 +33,7 @@ class ScanPathAnalyzer(GazeFeatures.ScanPathAnalyzer):
 
         self.__explore_exploit_ratio = 0.
 
+    @DataFeatures.PipelineStep
     def analyze(self, scan_path: GazeFeatures.ScanPathType):
 
         assert(len(scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/FocusPointInside.py b/src/argaze/GazeAnalysis/FocusPointInside.py
index e7da766..62ce054 100644
--- a/src/argaze/GazeAnalysis/FocusPointInside.py
+++ b/src/argaze/GazeAnalysis/FocusPointInside.py
@@ -12,7 +12,7 @@ from typing import TypeVar, Tuple
 from dataclasses import dataclass, field
 import math
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 from argaze.AreaOfInterest import AOIFeatures
 
 import numpy
@@ -30,6 +30,7 @@ class AOIMatcher(GazeFeatures.AOIMatcher):
         self.__looked_aoi_data = (None, None)
         self.__matched_gaze_movement = None
 
+    @DataFeatures.PipelineStep
     def match(self, aoi_scene, gaze_movement) -> Tuple[str, AOIFeatures.AreaOfInterest]:
         """Returns AOI containing fixation focus point."""
 
diff --git a/src/argaze/GazeAnalysis/KCoefficient.py b/src/argaze/GazeAnalysis/KCoefficient.py
index c8fa398..c6dfa15 100644
--- a/src/argaze/GazeAnalysis/KCoefficient.py
+++ b/src/argaze/GazeAnalysis/KCoefficient.py
@@ -10,7 +10,7 @@ __license__ = "BSD"
 
 from dataclasses import dataclass
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import numpy
 
@@ -30,6 +30,7 @@ class ScanPathAnalyzer(GazeFeatures.ScanPathAnalyzer):
 
         self.__K = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, scan_path: GazeFeatures.ScanPathType):
 
         assert(len(scan_path) > 1)
@@ -86,6 +87,7 @@ class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
 
         self.__K = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: GazeFeatures.AOIScanPathType) -> float:
 
         assert(len(aoi_scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/LempelZivComplexity.py b/src/argaze/GazeAnalysis/LempelZivComplexity.py
index 552ad75..67e5001 100644
--- a/src/argaze/GazeAnalysis/LempelZivComplexity.py
+++ b/src/argaze/GazeAnalysis/LempelZivComplexity.py
@@ -10,7 +10,7 @@ __license__ = "BSD"
 
 from dataclasses import dataclass
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 from lempel_ziv_complexity import lempel_ziv_complexity
 
@@ -31,6 +31,7 @@ class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
 
         self.__lempel_ziv_complexity = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: GazeFeatures.AOIScanPathType):
 
         assert(len(aoi_scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/NGram.py b/src/argaze/GazeAnalysis/NGram.py
index 903c0c0..b1e5ab3 100644
--- a/src/argaze/GazeAnalysis/NGram.py
+++ b/src/argaze/GazeAnalysis/NGram.py
@@ -11,7 +11,7 @@ __license__ = "BSD"
 from typing import TypeVar, Tuple, Any
 from dataclasses import dataclass, field
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 @dataclass
 class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
@@ -35,6 +35,7 @@ class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
 
         self.__ngrams_count = {}
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: GazeFeatures.AOIScanPathType):
 
         assert(len(aoi_scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/NearestNeighborIndex.py b/src/argaze/GazeAnalysis/NearestNeighborIndex.py
index 1ca336f..1dc692e 100644
--- a/src/argaze/GazeAnalysis/NearestNeighborIndex.py
+++ b/src/argaze/GazeAnalysis/NearestNeighborIndex.py
@@ -11,7 +11,7 @@ __license__ = "BSD"
 from typing import TypeVar, Tuple, Any
 from dataclasses import dataclass, field
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import numpy
 from scipy.spatial.distance import cdist
@@ -35,6 +35,7 @@ class ScanPathAnalyzer(GazeFeatures.ScanPathAnalyzer):
 
         self.__nearest_neighbor_index = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, scan_path: GazeFeatures.ScanPathType):
 
         assert(len(scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/TransitionMatrix.py b/src/argaze/GazeAnalysis/TransitionMatrix.py
index 5e3bdf5..313c945 100644
--- a/src/argaze/GazeAnalysis/TransitionMatrix.py
+++ b/src/argaze/GazeAnalysis/TransitionMatrix.py
@@ -11,7 +11,7 @@ __license__ = "BSD"
 from typing import Tuple
 from dataclasses import dataclass
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import pandas
 import numpy
@@ -33,6 +33,7 @@ class AOIScanPathAnalyzer(GazeFeatures.AOIScanPathAnalyzer):
         self.__transition_matrix_probabilities = pandas.DataFrame()
         self.__transition_matrix_density = 0.
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: GazeFeatures.AOIScanPathType):
 
         assert(len(aoi_scan_path) > 1)
diff --git a/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py b/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
index e9f770a..1e486e1 100644
--- a/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
+++ b/src/argaze/GazeAnalysis/VelocityThresholdIdentification.py
@@ -11,7 +11,7 @@ from typing import TypeVar, Tuple
 from dataclasses import dataclass, field
 import math
 
-from argaze import GazeFeatures
+from argaze import GazeFeatures, DataFeatures
 
 import numpy
 import cv2
@@ -142,6 +142,7 @@ class GazeMovementIdentifier(GazeFeatures.GazeMovementIdentifier):
         self.__fixation_positions = GazeFeatures.TimeStampedGazePositions()
         self.__saccade_positions = GazeFeatures.TimeStampedGazePositions()
 
+    @DataFeatures.PipelineStep
     def identify(self, ts, gaze_position, terminate=False) -> GazeMovementType:
 
         # Ignore non valid gaze position
diff --git a/src/argaze/GazeFeatures.py b/src/argaze/GazeFeatures.py
index a57a127..c9269e0 100644
--- a/src/argaze/GazeFeatures.py
+++ b/src/argaze/GazeFeatures.py
@@ -523,6 +523,7 @@ class TimeStampedGazeStatus(DataFeatures.TimeStampedBuffer):
 class GazeMovementIdentifier():
     """Abstract class to define what should provide a gaze movement identifier."""
 
+    @DataFeatures.PipelineStep
     def identify(self, timestamp: int|float, gaze_position: GazePosition, terminate:bool=False) -> Tuple[GazeMovementType, GazeMovementType]:
         """Identify gaze movement from successive timestamped gaze positions. 
         Each identified gaze movement should share its first/last gaze position with previous/next gaze movement.
@@ -835,6 +836,7 @@ class ScanPathAnalyzer():
 
         return DataFeatures.DataDictionary(analysis)
 
+    @DataFeatures.PipelineStep
     def analyze(self, scan_path: ScanPathType):
         """Analyze scan path."""
 
@@ -1172,6 +1174,7 @@ class AOIScanPathAnalyzer():
 
         return DataFeatures.DataDictionary(analysis)
 
+    @DataFeatures.PipelineStep
     def analyze(self, aoi_scan_path: AOIScanPathType):
         """Analyze aoi scan path."""
 
diff --git a/src/argaze/PupillAnalysis/WorkloadIndex.py b/src/argaze/PupillAnalysis/WorkloadIndex.py
index 4a20091..1429eaf 100644
--- a/src/argaze/PupillAnalysis/WorkloadIndex.py
+++ b/src/argaze/PupillAnalysis/WorkloadIndex.py
@@ -33,6 +33,7 @@ class PupillDiameterAnalyzer(PupillFeatures.PupillDiameterAnalyzer):
         self.__variations_number = 0
         self.__last_ts = 0
 
+    @DataFeatures.PipelineStep
     def analyze(self, ts, pupill_diameter) -> float:
         """Analyze workload index from successive timestamped pupill diameters."""
 
diff --git a/src/argaze/PupillFeatures.py b/src/argaze/PupillFeatures.py
index d751af6..5eb70ce 100644
--- a/src/argaze/PupillFeatures.py
+++ b/src/argaze/PupillFeatures.py
@@ -82,6 +82,7 @@ TimeStampedBufferType = TypeVar('TimeStampedBuffer', bound="TimeStampedBuffer")
 class PupillDiameterAnalyzer():
     """Abstract class to define what should provide a pupill diameter analyser."""
 
+    @DataFeatures.PipelineStep
     def analyze(self, ts, pupill_diameter) -> float:
         """Analyze pupill diameter from successive timestamped pupill diameters."""
 
diff --git a/src/argaze/utils/demo_data/demo_gaze_analysis_setup.json b/src/argaze/utils/demo_data/demo_gaze_analysis_setup.json
index 71006f2..2763a27 100644
--- a/src/argaze/utils/demo_data/demo_gaze_analysis_setup.json
+++ b/src/argaze/utils/demo_data/demo_gaze_analysis_setup.json
@@ -52,8 +52,8 @@
                     "FileWriter" : {
                         "path": "_export/logs/aoi_scan_path_metrics.csv",
                         "header": "Timestamp (ms), Duration (ms), Step, K, LZC",
-                        "selector": "len(aoi_scan_path_analysis) > 0",
-                        "formatter": "timestamp, aoi_scan_path_analysis['argaze.GazeAnalysis.Basic'].path_duration, aoi_scan_path_analysis['argaze.GazeAnalysis.Basic'].steps_number, aoi_scan_path_analysis['argaze.GazeAnalysis.KCoefficient'].K, aoi_scan_path_analysis['argaze.GazeAnalysis.LempelZivComplexity'].lempel_ziv_complexity"
+                        "selector": "self.new_analysis_available",
+                        "formatter": "timestamp, self.aoi_scan_path_analyzers['argaze.GazeAnalysis.Basic'].path_duration, self.aoi_scan_path_analyzers['argaze.GazeAnalysis.Basic'].steps_number, self.aoi_scan_path_analyzers['argaze.GazeAnalysis.KCoefficient'].K, self.aoi_scan_path_analyzers['argaze.GazeAnalysis.LempelZivComplexity'].lempel_ziv_complexity"
                     }
                 }
             }
@@ -64,16 +64,23 @@
             "FileWriter" : {
                 "path": "_export/logs/Fixations.csv",
                 "header": "Timestamp (ms), Focus (px), Duration (ms), AOI",
-                "selector": "GazeFeatures.is_fixation(gaze_movement) and gaze_movement.finished",
-                "formatter": "timestamp, gaze_movement.focus, gaze_movement.duration, layers.main_layer.looked_aoi_name"
+                "selector": "GazeFeatures.is_fixation(self.gaze_movement) and self.gaze_movement.finished",
+                "formatter": "timestamp, self.gaze_movement.focus, self.gaze_movement.duration, self.layers['main_layer'].aoi_matcher.looked_aoi_name"
+            }
+        },
+        "messages": {
+            "FileWriter" : {
+                "path": "_export/logs/Messages.csv",
+                "selector": "GazeFeatures.is_fixation(self.gaze_movement) and not self.gaze_movement.finished",
+                "formatter": "f'FixationInProgress Start={self.gaze_movement.positions.first[0]} Duration={self.gaze_movement.duration} AOI={self.layers[\"main_layer\"].aoi_matcher.looked_aoi_name} Probabilities={self.layers[\"main_layer\"].aoi_matcher.looked_probabilities}'"
             }
         },
         "scan_path_metrics": {
             "FileWriter" : {
                 "path": "_export/logs/scan_path_metrics.csv",
                 "header": "Timestamp (ms), Duration (ms), Step, K, NNI, XXR",
-                "selector": "len(scan_path_analysis) > 0",
-                "formatter": "timestamp, scan_path_analysis['argaze.GazeAnalysis.Basic'].path_duration, scan_path_analysis['argaze.GazeAnalysis.Basic'].steps_number, scan_path_analysis['argaze.GazeAnalysis.KCoefficient'].K, scan_path_analysis['argaze.GazeAnalysis.NearestNeighborIndex'].nearest_neighbor_index, scan_path_analysis['argaze.GazeAnalysis.ExploreExploitRatio'].explore_exploit_ratio"
+                "selector": "self.new_analysis_available",
+                "formatter": "timestamp, self.scan_path_analyzers['argaze.GazeAnalysis.Basic'].path_duration, self.scan_path_analyzers['argaze.GazeAnalysis.Basic'].steps_number, self.scan_path_analyzers['argaze.GazeAnalysis.KCoefficient'].K, self.scan_path_analyzers['argaze.GazeAnalysis.NearestNeighborIndex'].nearest_neighbor_index, self.scan_path_analyzers['argaze.GazeAnalysis.ExploreExploitRatio'].explore_exploit_ratio"
             }
         }
     },
diff --git a/src/argaze/utils/demo_gaze_analysis_run.py b/src/argaze/utils/demo_gaze_analysis_run.py
index 5f46596..210e188 100644
--- a/src/argaze/utils/demo_gaze_analysis_run.py
+++ b/src/argaze/utils/demo_gaze_analysis_run.py
@@ -50,7 +50,7 @@ def main():
         timestamp = int((time.time() - start_time) * 1e3)
 
         # Project gaze position into frame
-        ar_frame.look(timestamp, GazeFeatures.GazePosition((x, y)))
+        execution_time, exception = ar_frame.look(timestamp, GazeFeatures.GazePosition((x, y)))
 
     # Attach mouse callback to window
     cv2.setMouseCallback(ar_frame.name, on_mouse_event)