Merge pull request #2736 from forslund/docs/plugin-apis

Add Plugin base classes APIs to readthedocs

doc/index.rst

@@ -1,12 +1,24 @@
 .. Mycroft documentation master file
+Mycroft-core technical documentation
+====================================
 
 Mycroft Skills API
-==================
+------------------
 
-*Reference for the Mycroft Skills API*
+*Reference for use during Skill creation*
 
 .. toctree::
    :maxdepth: 4
    :caption: Contents:
    
    source/mycroft
+
+Mycroft plugin API
+------------------
+*Reference for use during Plugin creation*
+
+.. toctree::
+   :maxdepth: 4
+   :caption: Contents:
+
+   source/plugins

doc/source/plugins.rst

@@ -0,0 +1,36 @@
+Mycroft plugins
+===============
+Mycroft is extendable by plugins. These plugins can add support for new Speech To Text engines, Text To Speech engines, wake word engines and add new audio playback options.
+
+TTS - Base for TTS plugins
+--------------------------
+.. autoclass:: mycroft.tts.TTS
+    :members:
+
+STT - base for STT plugins
+--------------------------
+.. autoclass:: mycroft.stt.STT
+    :members:
+|
+|
+.. autoclass:: mycroft.stt.StreamingSTT
+    :members:
+|
+|
+.. autoclass:: mycroft.stt.StreamThread
+    :members:
+
+HotWordEngine - Base for Hotword engine plugins
+-----------------------------------------------
+.. autoclass:: mycroft.client.speech.hotword_factory.HotWordEngine
+    :members:
+
+AudioBackend - Base for audioservice backend plugins
+------------------
+.. autoclass:: mycroft.audio.services.AudioBackend
+    :members:
+|
+|
+.. autoclass:: mycroft.audio.services.RemoteAudioBackend
+    :members:
+

mycroft/audio/services/__init__.py

@@ -12,132 +12,129 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+"""Definition of the audio service backends base classes.
+
+These classes can be used to create an Audioservice plugin extending
+Mycroft's media playback options.
+"""
 from abc import ABCMeta, abstractmethod
 
 
 class AudioBackend(metaclass=ABCMeta):
-    """
+    """Base class for all audio backend implementations.
-        Base class for all audio backend implementations.
 
-        Args:
+    Arguments:
-            config: configuration dict for the instance
+        config (dict): configuration dict for the instance
-            bus:    Mycroft messagebus emitter
+        bus (MessageBusClient): Mycroft messagebus emitter
     """
 
     def __init__(self, config, bus):
         self._track_start_callback = None
         self.supports_mime_hints = False
+        self.config = config
+        self.bus = bus
 
     @abstractmethod
     def supported_uris(self):
+        """List of supported uri types.
+
+        Returns:
+            list: Supported uri's
         """
-            Returns: list of supported uri types.
-        """
-        pass
 
     @abstractmethod
     def clear_list(self):
-        """
+        """Clear playlist."""
-            Clear playlist
-        """
-        pass
 
     @abstractmethod
     def add_list(self, tracks):
-        """
+        """Add tracks to backend's playlist.
-            Add tracks to backend's playlist.
 
-            Args:
+        Arguments:
-                tracks: list of tracks.
+            tracks (list): list of tracks.
         """
-        pass
 
     @abstractmethod
     def play(self, repeat=False):
-        """
+        """Start playback.
-            Start playback.
 
-            Args:
+        Starts playing the first track in the playlist and will contiune
-                repeat: Repeat playlist, defaults to False
+        until all tracks have been played.
+
+        Arguments:
+            repeat (bool): Repeat playlist, defaults to False
         """
-        pass
 
     @abstractmethod
     def stop(self):
-        """
+        """Stop playback.
-            Stop playback.
 
-            Returns: (bool) True if playback was stopped, otherwise False
+        Stops the current playback.
+
+        Returns:
+            bool: True if playback was stopped, otherwise False
         """
-        pass
 
     def set_track_start_callback(self, callback_func):
-        """
+        """Register callback on track start.
-            Register callback on track start, should be called as each track
+
-            in a playlist is started.
+        This method should be called as each track in a playlist is started.
         """
         self._track_start_callback = callback_func
 
     def pause(self):
+        """Pause playback.
+
+        Stops playback but may be resumed at the exact position the pause
+        occured.
         """
-            Pause playback.
-        """
-        pass
 
     def resume(self):
+        """Resume paused playback.
+
+        Resumes playback after being paused.
         """
-            Resume paused playback.
-        """
-        pass
 
     def next(self):
-        """
+        """Skip to next track in playlist."""
-            Skip to next track in playlist.
-        """
-        pass
 
     def previous(self):
-        """
+        """Skip to previous track in playlist."""
-            Skip to previous track in playlist.
-        """
-        pass
 
     def lower_volume(self):
+        """Lower volume.
+
+        This method is used to implement audio ducking. It will be called when
+        Mycroft is listening or speaking to make sure the media playing isn't
+        interfering.
         """
-            Lower volume.
-        """
-        pass
 
     def restore_volume(self):
+        """Restore normal volume.
+
+        Called when to restore the playback volume to previous level after
+        Mycroft has lowered it using lower_volume().
         """
-            Restore normal volume.
-        """
-        pass
 
     def seek_forward(self, seconds=1):
-        """
+        """Skip X seconds.
-            Skip X seconds
 
-            Args:
+        Arguments:
             seconds (int): number of seconds to seek, if negative rewind
         """
-        pass
 
     def seek_backward(self, seconds=1):
-        """
+        """Rewind X seconds.
-            Rewind X seconds
 
-            Args:
+        Arguments:
-                seconds (int): number of seconds to seek, if negative rewind
+            seconds (int): number of seconds to seek, if negative jump forward.
         """
-        pass
 
     def track_info(self):
-        """
+        """Get info about current playing track.
-            Fetch info about current playing track.
 
         Returns:
-                Dict with track info.
+            dict: Track info containing atleast the keys artist and album.
         """
         ret = {}
         ret['artist'] = ''
@@ -145,13 +142,19 @@ class AudioBackend(metaclass=ABCMeta):
         return ret
 
     def shutdown(self):
-        """ Perform clean shutdown """
+        """Perform clean shutdown.
+
+        Implements any audio backend specific shutdown procedures.
+        """
         self.stop()
 
 
 class RemoteAudioBackend(AudioBackend):
-    """ Base class for remote audio backends.
+    """Base class for remote audio backends.
 
-        These may be things like Chromecasts, mopidy servers, etc.
+    RemoteAudioBackends will always be checked after the normal
+    AudioBackends to make playback start locally by default.
+
+    An example of a RemoteAudioBackend would be things like Chromecasts,
+    mopidy servers, etc.
     """
-    pass

mycroft/client/speech/hotword_factory.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+"""Factory functions for loading hotword engines - both internal and plugins.
+"""
 from time import time, sleep
 import os
 import platform
@@ -54,12 +56,19 @@ def msec_to_sec(msecs):
         msecs: milliseconds
 
     Returns:
-        input converted from milliseconds to seconds
+        int: input converted from milliseconds to seconds
     """
     return msecs / 1000
 
 
 class HotWordEngine:
+    """Hotword/Wakeword base class to be implemented by all wake word plugins.
+
+    Arguments:
+        key_phrase (str): string representation of the wake word
+        config (dict): Configuration block for the specific wake word
+        lang (str): language code (BCP-47)
+    """
     def __init__(self, key_phrase="hey mycroft", config=None, lang="en-us"):
         self.key_phrase = str(key_phrase).lower()
 
@@ -77,25 +86,43 @@ class HotWordEngine:
         self.lang = str(self.config.get("lang", lang)).lower()
 
     def found_wake_word(self, frame_data):
+        """Check if wake word has been found.
+
+        Checks if the wake word has been found. Should reset any internal
+        tracking of the wake word state.
+
+        Arguments:
+            frame_data (binary data): Deprecated. Audio data for large chunk
+                                      of audio to be processed. This should not
+                                      be used to detect audio data instead
+                                      use update() to incrementaly update audio
+        Returns:
+            bool: True if a wake word was detected, else False
+        """
         return False
 
     def update(self, chunk):
-        pass
+        """Updates the hotword engine with new audio data.
+
+        The engine should process the data and update internal trigger state.
+
+        Arguments:
+            chunk (bytes): Chunk of audio data to process
+        """
 
     def stop(self):
-        """ Perform any actions needed to shut down the hot word engine.
+        """Perform any actions needed to shut down the wake word engine.
 
-            This may include things such as unload loaded data or shutdown
+        This may include things such as unloading data or shutdown
         external processess.
         """
-        pass
 
 
 class PocketsphinxHotWord(HotWordEngine):
-    """Hotword engine using PocketSphinx.
+    """Wake word engine using PocketSphinx.
 
     PocketSphinx is very general purpose but has a somewhat high error rate.
-    The key advantage is to be able to specify the wakeword with phonemes.
+    The key advantage is to be able to specify the wake word with phonemes.
     """
     def __init__(self, key_phrase="hey mycroft", config=None, lang="en-us"):
         super().__init__(key_phrase, config, lang)
@@ -154,7 +181,7 @@ class PocketsphinxHotWord(HotWordEngine):
 
 
 class PreciseHotword(HotWordEngine):
-    """Precice is the default wakeword engine for mycroft.
+    """Precise is the default wake word engine for Mycroft.
 
     Precise is developed by Mycroft AI and produces quite good wake word
     spotting when trained on a decent dataset.
@@ -301,7 +328,7 @@ class PreciseHotword(HotWordEngine):
 
 
 class SnowboyHotWord(HotWordEngine):
-    """Snowboy is a thirdparty hotword engine providing an easy training and
+    """Snowboy is a thirdparty wake word engine providing an easy training and
     testing interface.
     """
     def __init__(self, key_phrase="hey mycroft", config=None, lang="en-us"):
@@ -410,6 +437,11 @@ def load_wake_word_plugin(module_name):
 
 
 class HotWordFactory:
+    """Factory class instantiating the configured Hotword engine.
+
+    The factory can select between a range of built-in Hotword engines and also
+    from Hotword engine plugins.
+    """
     CLASSES = {
         "pocketsphinx": PocketsphinxHotWord,
         "precise": PreciseHotword,

mycroft/stt/__init__.py

@@ -27,7 +27,7 @@ from mycroft.util.plugins import load_plugin
 
 
 class STT(metaclass=ABCMeta):
-    """ STT Base class, all  STT backends derives from this one. """
+    """STT Base class, all STT backends derive from this one. """
     def __init__(self):
         config_core = Configuration.get()
         self.lang = str(self.init_language(config_core))
@@ -39,6 +39,7 @@ class STT(metaclass=ABCMeta):
 
     @staticmethod
     def init_language(config_core):
+        """Helper method to get language code from Mycroft config."""
         lang = config_core.get("lang", "en-US")
         langs = lang.split("-")
         if len(langs) == 2:
@@ -47,7 +48,21 @@ class STT(metaclass=ABCMeta):
 
     @abstractmethod
     def execute(self, audio, language=None):
-        pass
+        """Implementation of STT functionallity.
+
+        This method needs to be implemented by the derived class to implement
+        the specific STT engine connection.
+
+        The method gets passed audio and optionally a language code and is
+        expected to return a text string.
+
+        Arguments:
+            audio (AudioData): audio recorded by mycroft.
+            language (str): optional language code
+
+        Returns:
+            str: parsed text
+        """
 
 
 class TokenSTT(STT, metaclass=ABCMeta):
@@ -322,8 +337,14 @@ class DeepSpeechServerSTT(STT):
 
 
 class StreamThread(Thread, metaclass=ABCMeta):
-    """
+    """ABC class to be used with StreamingSTT class implementations.
-        ABC class to be used with StreamingSTT class implementations.
+
+    This class reads audio chunks from a queue and sends it to a parsing
+    STT engine.
+
+    Arguments:
+        queue (Queue): Input Queue
+        language (str): language code for the current language.
     """
 
     def __init__(self, queue, language):
@@ -333,6 +354,7 @@ class StreamThread(Thread, metaclass=ABCMeta):
         self.text = None
 
     def _get_data(self):
+        """Generator reading audio data from queue."""
         while True:
             d = self.queue.get()
             if d is None:
@@ -341,23 +363,38 @@ class StreamThread(Thread, metaclass=ABCMeta):
             self.queue.task_done()
 
     def run(self):
+        """Thread entry point."""
         return self.handle_audio_stream(self._get_data(), self.language)
 
     @abstractmethod
     def handle_audio_stream(self, audio, language):
-        pass
+        """Handling of audio stream.
+
+        Needs to be implemented by derived class to process audio data and
+        optionally update `self.text` with the current hypothesis.
+
+        Argumens:
+            audio (bytes): raw audio data.
+            language (str): language code for the current session.
+        """
 
 
 class StreamingSTT(STT, metaclass=ABCMeta):
-    """
+    """ABC class for threaded streaming STT implemenations."""
-        ABC class for threaded streaming STT implemenations.
-    """
     def __init__(self):
         super().__init__()
         self.stream = None
         self.can_stream = True
 
     def stream_start(self, language=None):
+        """Indicate start of new audio stream.
+
+        This creates a new thread for handling the incomming audio stream as
+        it's collected by Mycroft.
+
+        Arguments:
+            language (str): optional language code for the new stream.
+        """
         self.stream_stop()
         language = language or self.lang
         self.queue = Queue()
@@ -365,9 +402,21 @@ class StreamingSTT(STT, metaclass=ABCMeta):
         self.stream.start()
 
     def stream_data(self, data):
+        """Receiver of audio data.
+
+        Arguments:
+            data (bytes): raw audio data.
+        """
         self.queue.put(data)
 
     def stream_stop(self):
+        """Indicate that the audio stream has ended.
+
+        This will tear down the processing thread and collect the result
+
+        Returns:
+            str: parsed text
+        """
         if self.stream is not None:
             self.queue.put(None)
             self.stream.join()
@@ -380,11 +429,20 @@ class StreamingSTT(STT, metaclass=ABCMeta):
         return None
 
     def execute(self, audio, language=None):
+        """End the parsing thread and collect data."""
         return self.stream_stop()
 
     @abstractmethod
     def create_streaming_thread(self):
-        pass
+        """Create thread for parsing audio chunks.
+
+        This method should be implemented by the derived class to return an
+        instance derived from StreamThread to handle the audio stream and
+        send it to the STT engine.
+
+        Returns:
+            StreamThread: Thread to handle audio data.
+        """
 
 
 class DeepSpeechStreamThread(StreamThread):
@@ -550,7 +608,9 @@ def load_stt_plugin(module_name):
     """Wrapper function for loading stt plugin.
 
     Arguments:
-        (str) Mycroft stt module name from config
+        module_name (str): Mycroft stt module name from config
+    Returns:
+        class: STT plugin class
     """
     return load_plugin('mycroft.plugin.stt', module_name)
 

mycroft/tts/tts.py

@@ -128,10 +128,10 @@ class PlaybackThread(Thread):
         """Send viseme data to enclosure
 
         Arguments:
-            pairs(list): Visime and timing pair
+            pairs (list): Visime and timing pair
 
         Returns:
-            True if button has been pressed.
+            bool: True if button has been pressed.
         """
         if self.enclosure:
             self.enclosure.mouth_viseme(time(), pairs)
@@ -187,7 +187,7 @@ class TTS(metaclass=ABCMeta):
         self.tts_name = type(self).__name__
 
     def load_spellings(self):
-        """Load phonetic spellings of words as dictionary"""
+        """Load phonetic spellings of words as dictionary."""
         path = join('text', self.lang.lower(), 'phonetic_spellings.txt')
         spellings_file = resolve_resource_file(path)
         if not spellings_file:
@@ -202,7 +202,7 @@ class TTS(metaclass=ABCMeta):
             return {}
 
     def begin_audio(self):
-        """Helper function for child classes to call in execute()"""
+        """Helper function for child classes to call in execute()."""
         # Create signals informing start of speech
         self.bus.emit(Message("recognizer_loop:audio_output_start"))
 
@@ -254,11 +254,23 @@ class TTS(metaclass=ABCMeta):
         pass
 
     def modify_tag(self, tag):
-        """Override to modify each supported ssml tag"""
+        """Override to modify each supported ssml tag.
+
+        Arguments:
+            tag (str): SSML tag to check and possibly transform.
+        """
         return tag
 
     @staticmethod
     def remove_ssml(text):
+        """Removes SSML tags from a string.
+
+        Arguments:
+            text (str): input string
+
+        Returns:
+            str: input string stripped from tags.
+        """
         return re.sub('<[^>]*>', '', text).replace('  ', ' ')
 
     def validate_ssml(self, utterance):
@@ -267,10 +279,10 @@ class TTS(metaclass=ABCMeta):
         Remove unsupported / invalid tags
 
         Arguments:
-            utterance(str): Sentence to validate
+            utterance (str): Sentence to validate
 
         Returns:
-            validated_sentence (str)
+            str: validated_sentence
         """
         # if ssml is not supported by TTS engine remove all tags
         if not self.ssml_tags:
@@ -310,9 +322,9 @@ class TTS(metaclass=ABCMeta):
         sentence.
 
         Arguments:
-                sentence:   Sentence to be spoken
+            sentence: (str) Sentence to be spoken
-                ident:      Id reference to current interaction
+            ident: (str) Id reference to current interaction
-                listen:     True if listen should be triggered at the end
+            listen: (bool) True if listen should be triggered at the end
                     of the utterance.
         """
         sentence = self.validate_ssml(sentence)
@@ -357,11 +369,16 @@ class TTS(metaclass=ABCMeta):
             self.queue.put((self.audio_ext, wav_file, vis, ident, l))
 
     def viseme(self, phonemes):
-        """Create visemes from phonemes. Needs to be implemented for all
+        """Create visemes from phonemes.
-            tts backends.
+
+        May be implemented to convert TTS phonemes into Mycroft mouth
+        visuals.
 
         Arguments:
-                phonemes(str): String with phoneme data
+            phonemes (str): String with phoneme data
+
+        Returns:
+            list: visemes
         """
         return None
 
@@ -384,8 +401,8 @@ class TTS(metaclass=ABCMeta):
         """Cache phonemes
 
         Arguments:
-            key:        Hash key for the sentence
+            key (str):        Hash key for the sentence
-            phonemes:   phoneme string to save
+            phonemes (str):   phoneme string to save
         """
         cache_dir = mycroft.util.get_cache_directory("tts/" + self.tts_name)
         pho_file = os.path.join(cache_dir, key + ".pho")
@@ -400,7 +417,7 @@ class TTS(metaclass=ABCMeta):
         """Load phonemes from cache file.
 
         Arguments:
-            Key:    Key identifying phoneme cache
+            key (str): Key identifying phoneme cache
         """
         pho_file = os.path.join(
             mycroft.util.get_cache_directory("tts/" + self.tts_name),
@@ -436,6 +453,7 @@ class TTSValidator(metaclass=ABCMeta):
         self.validate_connection()
 
     def validate_dependencies(self):
+        """Determine if all the TTS's external dependencies are satisfied."""
         pass
 
     def validate_instance(self):
@@ -454,15 +472,19 @@ class TTSValidator(metaclass=ABCMeta):
 
     @abstractmethod
     def validate_lang(self):
-        pass
+        """Ensure the TTS supports current language."""
 
     @abstractmethod
     def validate_connection(self):
-        pass
+        """Ensure the TTS can connect to it's backend.
+
+        This can mean for example being able to launch the correct executable
+        or contact a webserver.
+        """
 
     @abstractmethod
     def get_tts_class(self):
-        pass
+        """Return TTS class that this validator is for."""
 
 
 def load_tts_plugin(module_name):
@@ -470,11 +492,18 @@ def load_tts_plugin(module_name):
 
     Arguments:
         (str) Mycroft tts module name from config
+    Returns:
+        class: found tts plugin class
     """
     return load_plugin('mycroft.plugin.tts', module_name)
 
 
 class TTSFactory:
+    """Factory class instantiating the configured TTS engine.
+
+    The factory can select between a range of built-in TTS engines and also
+    from TTS engine plugins.
+    """
     from mycroft.tts.festival_tts import Festival
     from mycroft.tts.espeak_tts import ESpeak
     from mycroft.tts.fa_tts import FATTS