1  """The Inventory"""
 2  
 3  # TODO make this dynamic, and watch out for frozen, like with messagetypes
 4  import storage.filesystem
 5  import storage.sqlite
 6  from bmconfigparser import config
 7  
 8  
 9  def create_inventory_instance(backend="sqlite"):
10      """
11      Create an instance of the inventory class
12      defined in `storage.<backend>`.
13      """
14      return getattr(
15          getattr(storage, backend),
16          "{}Inventory".format(backend.title()))()
17  
18  
19  class Inventory:
20      """
21      Inventory class which uses storage backends
22      to manage the inventory.
23      """
24      def __init__(self):
25          self._moduleName = config.safeGet("inventory", "storage")
26          self._realInventory = create_inventory_instance(self._moduleName)
27          self.numberOfInventoryLookupsPerformed = 0
28  
29      # cheap inheritance copied from asyncore
30      def __getattr__(self, attr):
31          if attr == "__contains__":
32              self.numberOfInventoryLookupsPerformed += 1
33          try:
34              realRet = getattr(self._realInventory, attr)
35          except AttributeError:
36              raise AttributeError(
37                  "%s instance has no attribute '%s'" %
38                  (self.__class__.__name__, attr)
39              )
40          else:
41              return realRet
42  
43      # hint for pylint: this is dictionary like object
44      def __getitem__(self, key):
45          return self._realInventory[key]
46  
47      def __setitem__(self, key, value):
48          self._realInventory[key] = value