ext: Add basic global registry and switch to Extension.setup()

mopidy/__main__.py

@@ -84,7 +84,6 @@ def main():
                 enabled_extensions.append(extension)
 
         log_extension_info(installed_extensions, enabled_extensions)
-        ext.register_gstreamer_elements(enabled_extensions)
 
         # Config and deps commands are simply special cased for now.
         if args.command == config_cmd:
@@ -108,16 +107,13 @@ def main():
                 args.extension.ext_name)
             return 1
 
-        registry = {'backends': [], 'frontends': [], 'local:library': []}
         for extension in enabled_extensions:
-            registry['backends'].extend(extension.get_backend_classes())
+            extension.setup()
-            registry['frontends'].extend(extension.get_frontend_classes())
-            registry['local:library'].extend(extension.get_library_updaters())
 
         # Anything that wants to exit after this point must use
         # mopidy.utils.process.exit_process as actors can have been started.
         try:
-            return args.command.run(args, proxied_config, registry)
+            return args.command.run(args, proxied_config)
         except NotImplementedError:
             print root_cmd.format_help()
             return 1

mopidy/backends/local/commands.py

@@ -4,7 +4,7 @@ import logging
 import os
 import time
 
-from mopidy import commands, exceptions
+from mopidy import commands, exceptions, ext
 from mopidy.audio import scan
 from mopidy.utils import path
 
@@ -22,14 +22,15 @@ class LocalCommand(commands.Command):
 class ScanCommand(commands.Command):
     help = "Scan local media files and populate the local library."
 
-    def run(self, args, config, registry):
+    def run(self, args, config):
         media_dir = config['local']['media_dir']
         scan_timeout = config['local']['scan_timeout']
+        excluded_file_extensions = config['local']['excluded_file_extensions']
         excluded_file_extensions = set(
-            ext.lower() for ext in config['local']['excluded_file_extensions'])
+            file_ext.lower() for file_ext in excluded_file_extensions)
 
         # TODO: select updater / library to use by name
-        updaters = registry['local:library']
+        updaters = ext.registry['local:library']
         if not updaters:
             logger.error('No usable library updaters found.')
             return 1

mopidy/commands.py

@@ -9,7 +9,7 @@ import sys
 import glib
 import gobject
 
-from mopidy import config as config_lib
+from mopidy import config as config_lib, ext
 from mopidy.audio import Audio
 from mopidy.core import Core
 from mopidy.utils import deps, process, versioning
@@ -257,22 +257,26 @@ class RootCommand(Command):
             type=config_override_type, metavar='OPTIONS',
             help='`section/key=value` values to override config options')
 
-    def run(self, args, config, registry):
+    def run(self, args, config):
         loop = gobject.MainLoop()
+
+        backend_classes = ext.registry['backend']
+        frontend_classes = ext.registry['frontend']
+
         try:
             audio = self.start_audio(config)
-            backends = self.start_backends(config, registry, audio)
+            backends = self.start_backends(config, backend_classes, audio)
             core = self.start_core(audio, backends)
-            self.start_frontends(config, registry, core)
+            self.start_frontends(config, frontend_classes, core)
             loop.run()
         except KeyboardInterrupt:
             logger.info('Interrupted. Exiting...')
             return
         finally:
             loop.quit()
-            self.stop_frontends(registry)
+            self.stop_frontends(frontend_classes)
             self.stop_core()
-            self.stop_backends(registry)
+            self.stop_backends(backend_classes)
             self.stop_audio()
             process.stop_remaining_actors()
 
@@ -280,9 +284,7 @@ class RootCommand(Command):
         logger.info('Starting Mopidy audio')
         return Audio.start(config=config).proxy()
 
-    def start_backends(self, config, registry, audio):
+    def start_backends(self, config, backend_classes, audio):
-        backend_classes = registry['backends']
-
         logger.info(
             'Starting Mopidy backends: %s',
             ', '.join(b.__name__ for b in backend_classes) or 'none')
@@ -298,9 +300,7 @@ class RootCommand(Command):
         logger.info('Starting Mopidy core')
         return Core.start(audio=audio, backends=backends).proxy()
 
-    def start_frontends(self, config, registry, core):
+    def start_frontends(self, config, frontend_classes, core):
-        frontend_classes = registry['frontends']
-
         logger.info(
             'Starting Mopidy frontends: %s',
             ', '.join(f.__name__ for f in frontend_classes) or 'none')
@@ -308,18 +308,18 @@ class RootCommand(Command):
         for frontend_class in frontend_classes:
             frontend_class.start(config=config, core=core)
 
-    def stop_frontends(self, registry):
+    def stop_frontends(self, frontend_classes):
         logger.info('Stopping Mopidy frontends')
-        for frontend_class in registry['frontends']:
+        for frontend_class in frontend_classes:
             process.stop_actors_by_class(frontend_class)
 
     def stop_core(self):
         logger.info('Stopping Mopidy core')
         process.stop_actors_by_class(Core)
 
-    def stop_backends(self, registry):
+    def stop_backends(self, backend_classes):
         logger.info('Stopping Mopidy backends')
-        for backend_class in registry['backends']:
+        for backend_class in backend_classes:
             process.stop_actors_by_class(backend_class)
 
     def stop_audio(self):

mopidy/ext.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 
+import collections
 import logging
 import pkg_resources
 
@@ -61,6 +62,18 @@ class Extension(object):
         """
         pass
 
+    def setup(self):
+        for backend_class in self.get_backend_classes():
+            registry.add('backend', backend_class)
+
+        for frontend_class in self.get_frontend_classes():
+            registry.add('frontend', frontend_class)
+
+        for library_updater in self.get_library_updaters():
+            registry.add('local:library', library_updater)
+
+        self.register_gstreamer_elements()
+
     def get_frontend_classes(self):
         """List of frontend actor classes
 
@@ -112,6 +125,29 @@ class Extension(object):
         pass
 
 
+class _Registry(collections.Mapping):
+    def __init__(self):
+        self._registry = collections.defaultdict(list)
+
+    def add(self, name, cls):
+        self._registry[name].append(cls)
+
+    def __getitem__(self, name):
+        return self._registry[name]
+
+    def __iter__(self):
+        return iter(self._registry)
+
+    def __len__(self):
+        return len(self._registry)
+
+
+# TODO: document the registry
+# TODO: consider if we should avoid having this as a global and pass an
+#       instance from __main__ around instead?
+registry = _Registry()
+
+
 def load_extensions():
     """Find all installed extensions.
 
@@ -166,15 +202,3 @@ def validate_extension(extension):
         return False
 
     return True
-
-
-def register_gstreamer_elements(enabled_extensions):
-    """Registers custom GStreamer elements from extensions.
-
-    :param enabled_extensions: list of enabled extensions
-    """
-
-    for extension in enabled_extensions:
-        logger.debug(
-            'Registering GStreamer elements for: %s', extension.ext_name)
-        extension.register_gstreamer_elements()