Refactor mimic_tts to not load config when importing

Hitting the entire configuration fetching routine with call to the
backend is not polite to do when just importing the file. This moves the
config lookup out of the global scope and into special functions for
finding the mimic binary and looking up the data path for the subscriber
voices.

mycroft/tts/mimic_tts.py

@@ -32,26 +32,43 @@
 
 from .tts import TTS, TTSValidator
 
-CONFIG = Configuration.get().get("tts").get("mimic")
-DATA_DIR = expanduser(Configuration.get()['data_dir'])
 
-BIN = CONFIG.get("path",
-                 os.path.join(MYCROFT_ROOT_PATH, 'mimic', 'bin', 'mimic'))
+def get_mimic_binary():
+    """Find the mimic binary, either from config or from PATH.
 
-if not os.path.isfile(BIN):
-    # Search for mimic on the path
-    import distutils.spawn
+    Returns:
+        (str) path for mimic executable
+    """
+    config = Configuration.get().get("tts").get("mimic")
+
+    bin_ = config.get("path",
+                      os.path.join(MYCROFT_ROOT_PATH, 'mimic', 'bin', 'mimic'))
+
+    if not os.path.isfile(bin_):
+        # Search for mimic on the path
+        import distutils.spawn
+
+        bin_ = distutils.spawn.find_executable("mimic")
 
-    BIN = distutils.spawn.find_executable("mimic")
+    return bin_
 
-SUBSCRIBER_VOICES = {'trinity': join(DATA_DIR, 'voices/mimic_tn')}
+
+def get_subscriber_voices():
+    """Get dict of mimic voices exclusive to subscribers.
+
+    Returns:
+        (dict) map of voices to custom Mimic executables.
+    """
+    data_dir = expanduser(Configuration.get()['data_dir'])
+    return {'trinity': join(data_dir, 'voices/mimic_tn')}
 
 
 def download_subscriber_voices(selected_voice):
     """Function to download all premium voices.
 
     The function starts with the currently selected if applicable
     """
+    subscriber_voices = get_subscriber_voices()
 
     def make_executable(dest):
         """Call back function to make the downloaded file executable."""
@@ -61,7 +78,7 @@ def make_executable(dest):
         os.chmod(dest, file_stat.st_mode | stat.S_IEXEC)
 
     # First download the selected voice if needed
-    voice_file = SUBSCRIBER_VOICES.get(selected_voice)
+    voice_file = subscriber_voices.get(selected_voice)
     if voice_file is not None and not exists(voice_file):
         LOG.info('Voice doesn\'t exist, downloading')
         url = DeviceApi().get_subscriber_voice_url(selected_voice)
@@ -76,8 +93,8 @@ def make_executable(dest):
                       .format(selected_voice))
 
     # Download the rest of the subsciber voices as needed
-    for voice in SUBSCRIBER_VOICES:
-        voice_file = SUBSCRIBER_VOICES[voice]
+    for voice in subscriber_voices:
+        voice_file = subscriber_voices[voice]
         if not exists(voice_file):
             url = DeviceApi().get_subscriber_voice_url(voice)
             # Check we got an url
@@ -111,9 +128,12 @@ def __init__(self, lang, config):
             lang, config, MimicValidator(self), 'wav',
             ssml_tags=["speak", "ssml", "phoneme", "voice", "audio", "prosody"]
         )
+        self.default_binary = get_mimic_binary()
+
         self.clear_cache()
 
         # Download subscriber voices if needed
+        self.subscriber_voices = get_subscriber_voices()
         self.is_subscriber = DeviceApi().is_subscriber
         if self.is_subscriber:
             trd = Thread(target=download_subscriber_voices, args=[self.voice])
@@ -137,18 +157,19 @@ def modify_tag(self, tag):
     @property
     def args(self):
         """Build mimic arguments."""
-        if (self.voice in SUBSCRIBER_VOICES and
-                exists(SUBSCRIBER_VOICES[self.voice]) and self.is_subscriber):
+        subscriber_voices = self.subscriber_voices
+        if (self.voice in subscriber_voices and
+                exists(subscriber_voices[self.voice]) and self.is_subscriber):
             # Use subscriber voice
-            mimic_bin = SUBSCRIBER_VOICES[self.voice]
+            mimic_bin = subscriber_voices[self.voice]
             voice = self.voice
-        elif self.voice in SUBSCRIBER_VOICES:
+        elif self.voice in subscriber_voices:
             # Premium voice but bin doesn't exist, use ap while downloading
-            mimic_bin = BIN
+            mimic_bin = self.default_binary
             voice = 'ap'
         else:
             # Normal case use normal binary and selected voice
-            mimic_bin = BIN
+            mimic_bin = self.default_binary
             voice = self.voice
 
         args = [mimic_bin, '-voice', voice, '-psdur', '-ssml']
@@ -195,11 +216,12 @@ def validate_lang(self):
 
     def validate_connection(self):
         """Check that Mimic executable is found and works."""
+        mimic_bin = get_mimic_binary()
         try:
-            subprocess.call([BIN, '--version'])
+            subprocess.call([mimic_bin, '--version'])
         except Exception as err:
-            if BIN:
-                LOG.error('Failed to find mimic at: {}'.format(BIN))
+            if mimic_bin:
+                LOG.error('Failed to find mimic at: {}'.format(mimic_bin))
             else:
                 LOG.error('Mimic executable not found')
             raise Exception(

test/unittests/tts/test_mimic_tts.py

@@ -3,8 +3,9 @@
 import unittest
 from unittest import mock
 
-from mycroft.tts.mimic_tts import (Mimic, download_subscriber_voices, BIN,
-                                   SUBSCRIBER_VOICES)
+from mycroft.tts.mimic_tts import (Mimic, download_subscriber_voices,
+                                   get_mimic_binary,
+                                   get_subscriber_voices)
 
 
 device_instance_mock = mock.Mock(name='device_api_instance')
@@ -55,15 +56,17 @@ def test_viseme(self, _, mock_device_api):
     @mock.patch('mycroft.tts.mimic_tts.Thread')
     def test_subscriber(self, mock_thread, _, mock_device_api):
         mock_device_api.return_value = subscribed_device
-
+        default_mimic = get_mimic_binary()
+        trinity_mimic = get_subscriber_voices()['trinity']
         m = Mimic('en-US', {'voice': 'trinity'})
         mock_thread.assert_called_with(target=download_subscriber_voices,
                                        args=['trinity'])
         self.assertTrue(m.is_subscriber)
-        self.assertEqual(m.args, [BIN, '-voice', 'ap', '-psdur', '-ssml'])
+        self.assertEqual(m.args,
+                         [default_mimic, '-voice', 'ap', '-psdur', '-ssml'])
         with mock.patch('mycroft.tts.mimic_tts.exists') as mock_exists:
             mock_exists.return_value = True
-            self.assertEqual(m.args, [SUBSCRIBER_VOICES['trinity'], '-voice',
+            self.assertEqual(m.args, [trinity_mimic, '-voice',
                                       'trinity', '-psdur', '-ssml'])
 
     @mock.patch('mycroft.tts.mimic_tts.sleep')