Implement run command

Author: einarf

demosys/conf/default_settings.py

@@ -44,7 +44,7 @@
 # Empty effects tuple
 EFFECTS = ()
 
-EFFECT_MANAGER = 'demosys.effects.managers.single.SingleEffectManager'
+EFFECT_MANAGER = 'demosys.effects.managers.SingleEffectManager'
 
 
 # Additional directories shaders can be found

demosys/core/management/commands/run.py

@@ -0,0 +1,26 @@
+import demosys
+from demosys.core.management.base import BaseCommand
+from demosys.core.exceptions import ImproperlyConfigured
+from demosys.utils.module_loading import import_string
+from demosys.conf import settings
+
+
+class Command(BaseCommand):
+    help = "Run using the configured effect manager"
+
+    def add_arguments(self, parser):
+        pass
+
+    def handle(self, *args, **options):
+        demosys.setup()
+        manager_path = getattr(settings, 'EFFECT_MANAGER')
+        if not manager_path:
+            raise ImproperlyConfigured("EFFECT_MANAGER not properly configured in settings")
+        print(manager_path)
+        try:
+            manager_cls = import_string(manager_path)
+        except ImportError as e:
+            raise ImproperlyConfigured("EFFECT_MANAGER '{}' failed to initialize: {}".format(manager_path, e))
+
+        manager = manager_cls()
+        demosys.run(manager=manager)

demosys/effects/managers.py

@@ -65,6 +65,9 @@ def pre_load(self):
         Initialize the effect that should run.
         """
         effect_list = [cfg.cls() for name, cfg in effects.effects.items()]
+        if not self.active_effect:
+            self.active_effect = effect_list[0]
+
         for effect in effect_list:
             if effect.name == self.effect_module:
                 self.active_effect = effect