google-assistant-sdk/pushtotalk: add explicit locking

- remove end_of_utterance()
- stop recording from main thread with explicit locking

Change-Id: I07b24b8193560783945acde9f2b55e5533578ebd

Author: proppy

google-assistant-sdk/googlesamples/assistant/grpc/audio_helpers.py

@@ -267,16 +267,19 @@ def __init__(self, source, sink, iter_size, sample_width):
         self._iter_size = iter_size
         self._sample_width = sample_width
         self._volume_percentage = 50
-        self._end_of_utterance = threading.Event()
+        self._stop_recording = threading.Event()
+        self._source_lock = threading.RLock()
 
     def start_recording(self):
         """Start recording from the audio source."""
-        self._end_of_utterance.clear()
+        self._stop_recording.clear()
         self._source.start()
 
     def stop_recording(self):
         """Stop recording from the audio source."""
-        self._source.stop()
+        self._stop_recording.set()
+        with self._source_lock:
+            self._source.stop()
 
     def start_playback(self):
         """Start playback to the audio sink."""
@@ -287,9 +290,6 @@ def stop_playback(self):
         self._sink.flush()
         self._sink.stop()
 
-    def end_of_utterance(self):
-        self._end_of_utterance.set()
-
     @property
     def volume_percentage(self):
         """The current volume setting as an integer percentage (1-100)."""
@@ -302,7 +302,8 @@ def volume_percentage(self, new_volume_percentage):
     def read(self, size):
         """Read bytes from the source (if currently recording).
         """
-        return self._source.read(size)
+        with self._source_lock:
+            return self._source.read(size)
 
     def write(self, buf):
         """Write bytes to the sink (if currently playing).
@@ -319,7 +320,7 @@ def close(self):
     def __iter__(self):
         """Returns a generator reading data from the stream."""
         while True:
-            if self._end_of_utterance.is_set():
+            if self._stop_recording.is_set():
                 raise StopIteration
             yield self.read(self._iter_size)
 

google-assistant-sdk/googlesamples/assistant/grpc/pushtotalk.py

@@ -21,7 +21,6 @@
 import os.path
 import pathlib2 as pathlib
 import sys
-import threading
 import uuid
 
 import click
@@ -121,20 +120,21 @@ def assist(self):
         self.conversation_stream.start_recording()
         logging.info('Recording audio request.')
 
-        def iter_assist_requests():
+        def iter_log_assist_requests():
             for c in self.gen_assist_requests():
                 assistant_helpers.log_assist_request_without_audio(c)
                 yield c
-            self.conversation_stream.stop_recording()
+            logging.debug('Reached end of AssistRequest iteration.')
 
         # This generator yields AssistResponse proto messages
         # received from the gRPC Google Assistant API.
-        for resp in self.assistant.Assist(iter_assist_requests(),
+        for resp in self.assistant.Assist(iter_log_assist_requests(),
                                           self.deadline):
             assistant_helpers.log_assist_response_without_audio(resp)
             if resp.event_type == END_OF_UTTERANCE:
-                logging.info('End of audio request detected')
-                self.conversation_stream.end_of_utterance()
+                logging.info('End of audio request detected.')
+                logging.info('Stopping recording.')
+                self.conversation_stream.stop_recording()
             if resp.speech_results:
                 logging.info('Transcript of user request: "%s".',
                              ' '.join(r.transcript