better logs, keep message.context (#85)

* better logs, keep message.context

relates to OpenVoiceOS/ovos-ocp-audio-plugin#124

End of playlist! log was misleading, this commit makes it properly reflect this is end of track  (internal playlist of audio backend is a single track)

* reformat code

ovos_audio/audio.py

@@ -14,8 +14,10 @@
 from threading import Lock
 
 from ovos_bus_client.message import Message
+from ovos_bus_client.message import dig_for_message
 from ovos_config.config import Configuration
-from ovos_plugin_manager.audio import load_audio_service_plugins as load_plugins, find_audio_service_plugins, setup_audio_service
+from ovos_plugin_manager.audio import find_audio_service_plugins, \
+    setup_audio_service
 from ovos_plugin_manager.templates.audio import RemoteAudioBackend
 from ovos_utils.log import LOG
 from ovos_utils.process_utils import MonotonicEvent
@@ -205,17 +207,18 @@ def track_start(self, track):
         """Callback method called from the services to indicate start of
         playback of a track or end of playlist.
         """
+        m = dig_for_message() or Message("")
         if track:
             # Inform about the track about to start.
             LOG.debug('New track coming up!')
-            self.bus.emit(Message('mycroft.audio.playing_track',
-                                  data={'track': track}))
+            self.bus.emit(m.forward('mycroft.audio.playing_track',
+                                    data={'track': track}))
             self.current.ocp_start()
         else:
             # If no track is about to start last track of the queue has been
             # played.
-            LOG.debug('End of playlist!')
-            self.bus.emit(Message('mycroft.audio.queue_end'))
+            LOG.debug(f'End of track! {self.current} finished playback')
+            self.bus.emit(m.forward('mycroft.audio.queue_end'))
             self.current.ocp_stop()
 
     @require_native_source()