- Stop assistant playback only if there was a user request. This

prevents a PortAudio write on input-only stream error in the Assistant
SDK, see https://github.com/googlesamples/assistant-sdk-python/issues/185

- Make sure that user_request is always defined before returning it

- Use assistant.google.pushtotalk as a fallback if assistant.google is
not configured/available

platypush/backend/assistant/google/pushtotalk.py

@@ -159,6 +159,7 @@ class AssistantGooglePushtotalkBackend(Backend):
 
                 logging.info('Assistant conversation triggered')
                 continue_conversation = True
+                user_request = None
 
                 while continue_conversation:
                     (user_request, continue_conversation) = self.assistant.assist()
@@ -243,6 +244,8 @@ class SampleAssistant(object):
                 yield c
             self.conversation_stream.start_playback()
 
+        user_request = None
+
         # This generator yields AssistResponse proto messages
         # received from the gRPC Google Assistant API.
         for resp in self.assistant.Assist(iter_assist_requests(),
@@ -285,7 +288,9 @@ class SampleAssistant(object):
             concurrent.futures.wait(device_actions_futures)
 
         logging.info('Finished playing assistant response.')
-        self.conversation_stream.stop_playback()
+
+        if user_request:
+            self.conversation_stream.stop_playback()
         return (user_request, continue_conversation)
 
     def gen_assist_requests(self):

platypush/message/event/assistant/__init__.py

@@ -12,8 +12,11 @@ class AssistantEvent(Event):
         try:
             self._assistant = get_backend('assistant.google')
         except KeyError as e:
-            logging.warning('google.assistant backend not configured/initialized')
-            self._assistant = None
+            try:
+                self._assistant = get_backend('assistant.google.pushtotalk')
+            except KeyError as e:
+                logging.warning('google.assistant backend not configured/initialized')
+                self._assistant = None
 
 
 class ConversationStartEvent(AssistantEvent):

platypush/plugins/assistant/google/__init__.py

@@ -0,0 +1,18 @@
+from platypush.context import get_backend
+from platypush.message.response import Response
+
+from platypush.plugins import Plugin
+
+class AssistantGooglePlugin(Plugin):
+    def start_conversation(self):
+        assistant = get_backend('assistant.google')
+        assistant.start_conversation()
+        return Response(output='', errors=[])
+
+    def stop_conversation(self):
+        assistant = get_backend('assistant.google')
+        assistant.stop_conversation()
+        return Response(output='', errors=[])
+
+# vim:sw=4:ts=4:et:
+

platypush/plugins/assistant/google/pushtotalk.py

@@ -0,0 +1,18 @@
+from platypush.context import get_backend
+from platypush.message.response import Response
+
+from platypush.plugins import Plugin
+
+class AssistantGooglePushtotalkPlugin(Plugin):
+    def start_conversation(self):
+        assistant = get_backend('assistant.google.pushtotalk')
+        assistant.start_conversation()
+        return Response(output='', errors=[])
+
+    def stop_conversation(self):
+        assistant = get_backend('assistant.google.pushtotalk')
+        assistant.stop_conversation()
+        return Response(output='', errors=[])
+
+# vim:sw=4:ts=4:et:
+