slapos/recipe/librecipe/generic.py: GenericBaseRecipe's _ws is a lazy attribute now.

getWorkingSet() is slow and it is not always needed. So, it is better not to call it in __init__.

slapos/recipe/librecipe/generic.py

@@ -61,7 +61,13 @@ class GenericBaseRecipe(object):
     self._options(options) # Options Hook
     self.options = options.copy() # Updated options dict
 
-    self._ws = self.getWorkingSet()
+  @property
+  def _ws(self):
+    # getWorkingSet() is slow and it is not always needed.
+    # So _ws should be a lazy attribute.
+    if getattr(self, '_ws_internal', None) is None:
+      self._ws_internal = self.getWorkingSet()
+    return self._ws_internal
 
   def update(self):
     """By default update method does the same thing than install"""