Preperation to support different database backends

neo/Settings.py

@@ -146,13 +146,13 @@ def debug_storage_leveldb_path(self):
     def database_properties(self):
         return {'blockchain': {'path': self.chain_leveldb_path,
                                'skip_version_check': False,
-                               'backend': 'leveldb'},
+                               'backend': 'neo.Storage.Implementation.LevelDB.LevelDBImpl.LevelDBImpl'},
 
                 'notification': {'path': self.notification_leveldb_path,
-                                 'backend': 'leveldb'},
+                                 'backend': 'neo.Storage.Implementation.LevelDB.LevelDBImpl.LevelDBImpl'},
 
                 'debug': {'path': self.debug_storage_leveldb_path,
-                          'backend': 'leveldb'}
+                          'backend': 'neo.Storage.Implementation.LevelDB.LevelDBImpl.LevelDBImpl'}
                 }
 
     # Helpers

neo/Storage/Implementation/AbstractDBImplementation.py

@@ -1,17 +1,17 @@
 from abc import ABC, abstractmethod
 """
 Description:
-    Abstract class used to ensure the mandatory methods are overwritten
-    in everxy new database implementation.
+    Alternative backends can be added by implementing the required methods
+    of this abstract class.
 Usage:
     The dynamically generated class coming from the database factory inherits
-    from the abstract class, means the generated class cannot be used if not 
+    from the abstract class, means the generated class cannot be used if not
     all methods defined in this class are overwritten.
 
     If this class is extended, make sure you extend also all other database
     implementations.
 
-    For a more detailed information on the methods and how to implement a new 
+    For a more detailed information on the methods and how to implement a new
     database backend check out:
     neo.Storage.Implementation.LevelDB.LevelDBClassMethods
 """
@@ -48,9 +48,9 @@ def getBatch(self):
         raise NotImplementedError
 
     @abstractmethod
-    def closeDB(self):
+    def getPrefixedDB(self, prefix):
         raise NotImplementedError
 
     @abstractmethod
-    def getPrefixedDB(self, prefix):
+    def closeDB(self):
         raise NotImplementedError

neo/Storage/Implementation/DBFactory.py

@@ -1,9 +1,5 @@
-from neo.Storage.Implementation.AbstractDBImplementation import (
-    AbstractDBImplementation
-)
 from neo.Settings import settings
-from neo.logging import log_manager
-
+from neo.Utils.plugin import load_class_from_path
 
 """Database factory module
 
@@ -27,8 +23,6 @@
 
 """
 
-logger = log_manager.getLogger()
-
 BC_CONST = 'blockchain'
 NOTIF_CONST = 'notification'
 DEBUG_CONST = 'debug'
@@ -50,7 +44,7 @@ def getBlockchainDB(path=None):
     if not path:
         path = DATABASE_PROPS[BC_CONST]['path']
 
-    BlockchainDB = _dbFactory(BC_CONST, DATABASE_PROPS[BC_CONST])
+    BlockchainDB = load_class_from_path(DATABASE_PROPS[BC_CONST]['backend'])
     _blockchain_db_instance = BlockchainDB(path)
     return _blockchain_db_instance
 
@@ -69,7 +63,7 @@ def getNotificationDB(path=None):
     if not path:
         path = DATABASE_PROPS[NOTIF_CONST]['path']
 
-    NotificationDB = _dbFactory(NOTIF_CONST, DATABASE_PROPS[NOTIF_CONST])
+    NotificationDB = load_class_from_path(DATABASE_PROPS[NOTIF_CONST]['backend'])
     _notif_db_instance = NotificationDB(path)
     return _notif_db_instance
 
@@ -82,41 +76,6 @@ def getDebugStorageDB():
         _debug_db_instance (object): A new debug storage instance.
     """
 
-    DebugStorageDB = _dbFactory(DEBUG_CONST, DATABASE_PROPS[DEBUG_CONST])
+    DebugStorageDB = load_class_from_path(DATABASE_PROPS[DEBUG_CONST]['backend'])
     _debug_db_instance = DebugStorageDB(DATABASE_PROPS[DEBUG_CONST]['path'])
     return _debug_db_instance
-
-
-def _dbFactory(dbType, properties):
-    """ Method to generate a database class.
-
-    Args:
-        dbType (str): Type of the database (Blockchain, Notification, Debug).
-        properties (dict): The properties defined within the settings module.
-
-    Returns:
-        New database class to instantiate a new database.
-
-
-    """
-
-    if properties['backend'] == 'leveldb':
-
-        """
-        Module implements the methods used by the dynamically generated class.
-        """
-        import neo.Storage.Implementation.LevelDB.LevelDBClassMethods as functions
-
-        methods = [x for x in dir(functions) if not x.startswith('__')]
-
-        # build the dict containing all the attributes (methods + members)
-        attributes = {methods[i]: getattr(
-            functions, methods[i]) for i in range(0, len(methods))}
-
-        # add __init__ method
-        attributes['__init__'] = attributes.pop(functions._init_method)
-
-        return type(
-            properties['backend'].title() + 'DBImpl' + dbType.title(),
-            (AbstractDBImplementation,),
-            attributes)