From 41594c116e8f6a79e1ec1c4b60d8a6f673679bfd Mon Sep 17 00:00:00 2001
From: Stein Magnus Jodal <stein.magnus@jodal.no>
Date: Mon, 15 Apr 2013 22:43:51 +0200
Subject: [PATCH 1/2] ext: Split load into load+validate

---
 mopidy/__main__.py |  3 ++-
 mopidy/ext.py      | 60 ++++++++++++++++++++++++++++++++--------------
 2 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/mopidy/__main__.py b/mopidy/__main__.py
index 163f67ae..ad2b8c56 100644
--- a/mopidy/__main__.py
+++ b/mopidy/__main__.py
@@ -53,7 +53,8 @@ def main():
         logging_config = config_lib.load(config_files, config_overrides)
         log.setup_logging(
             logging_config, options.verbosity_level, options.save_debug_log)
-        extensions = ext.load_extensions()
+        installed_extensions = ext.load_extensions()
+        extensions = ext.validate_extensions(installed_extensions)
         raw_config = config_lib.load(config_files, config_overrides, extensions)
         extensions = ext.filter_enabled_extensions(raw_config, extensions)
         config = config_lib.validate(
diff --git a/mopidy/ext.py b/mopidy/ext.py
index 9cea1bd5..b97b45d3 100644
--- a/mopidy/ext.py
+++ b/mopidy/ext.py
@@ -91,42 +91,66 @@ class Extension(object):
 
 
 def load_extensions():
-    extensions = []
+    """Find all installed extensions.
+
+    :returns: list of installed extensions
+    """
+
+    installed_extensions = []
+
     for entry_point in pkg_resources.iter_entry_points('mopidy.ext'):
         logger.debug('Loading entry point: %s', entry_point)
-
-        try:
-            extension_class = entry_point.load()
-        except pkg_resources.DistributionNotFound as ex:
-            logger.info(
-                'Disabled extension %s: Dependency %s not found',
-                entry_point.name, ex)
-            continue
-
+        extension_class = entry_point.load(require=False)
         extension = extension_class()
-
+        extension.entry_point = entry_point
+        installed_extensions.append(extension)
         logger.debug(
             'Loaded extension: %s %s', extension.dist_name, extension.version)
 
-        if entry_point.name != extension.ext_name:
+    names = (e.ext_name for e in installed_extensions)
+    logging.debug('Discovered extensions: %s', ', '.join(names))
+    return installed_extensions
+
+
+def validate_extensions(installed_extensions):
+    """Verify extension's dependencies and environment.
+
+    :param installed_extensions: list of installed extensions
+    :returns: list of valid extensions
+    """
+
+    valid_extensions = []
+
+    for extension in installed_extensions:
+        logger.debug('Validating extension: %s', extension.ext_name)
+
+        if extension.ext_name != extension.entry_point.name:
             logger.warning(
                 'Disabled extension %(ep)s: entry point name (%(ep)s) '
                 'does not match extension name (%(ext)s)',
-                {'ep': entry_point.name, 'ext': extension.ext_name})
+                {'ep': extension.entry_point.name, 'ext': extension.ext_name})
+            continue
+
+        try:
+            extension.entry_point.require()
+        except pkg_resources.DistributionNotFound as ex:
+            logger.info(
+                'Disabled extension %s: Dependency %s not found',
+                extension.ext_name, ex)
             continue
 
         try:
             extension.validate_environment()
         except exceptions.ExtensionError as ex:
             logger.info(
-                'Disabled extension %s: %s', entry_point.name, ex.message)
+                'Disabled extension %s: %s', extension.ext_name, ex.message)
             continue
 
-        extensions.append(extension)
+        valid_extensions.append(extension)
 
-    names = (e.ext_name for e in extensions)
-    logging.debug('Discovered extensions: %s', ', '.join(names))
-    return extensions
+    names = (e.ext_name for e in valid_extensions)
+    logger.debug('Valid extensions: %s', ', '.join(names))
+    return valid_extensions
 
 
 def filter_enabled_extensions(raw_config, extensions):

From 2793a384c2360b3970c82c2815052b057ecd28ac Mon Sep 17 00:00:00 2001
From: Stein Magnus Jodal <stein.magnus@jodal.no>
Date: Mon, 15 Apr 2013 22:44:11 +0200
Subject: [PATCH 2/2] ext: Register ext's GStreamer elements

---
 mopidy/__main__.py |  1 +
 mopidy/ext.py      | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/mopidy/__main__.py b/mopidy/__main__.py
index ad2b8c56..cd082b9f 100644
--- a/mopidy/__main__.py
+++ b/mopidy/__main__.py
@@ -61,6 +61,7 @@ def main():
             raw_config, config_lib.core_schemas, extensions)
         log.setup_log_levels(config)
         check_old_locations()
+        ext.register_gstreamer_elements(extensions)
 
         # TODO: wrap config in RO proxy.
 
diff --git a/mopidy/ext.py b/mopidy/ext.py
index b97b45d3..45497a37 100644
--- a/mopidy/ext.py
+++ b/mopidy/ext.py
@@ -153,6 +153,18 @@ def validate_extensions(installed_extensions):
     return valid_extensions
 
 
+def register_gstreamer_elements(enabled_extensions):
+    """Registers custom GStreamer elements from extensions.
+
+    :params 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()
+
+
 def filter_enabled_extensions(raw_config, extensions):
     boolean = config_lib.Boolean()
     enabled_extensions = []