Move Singleton from Backend to Repository

jsonrepo/backend.py

@@ -4,11 +4,8 @@
 Author:   Romary Dupuis <romary@me.com>
 Copyright (C) 2017 Romary Dupuis
 """
-from six import add_metaclass
-from singleton import Singleton
 
 
-@add_metaclass(Singleton)
 class Backend(object):
     """ Basic backend class """
     def __init__(self, prefix):

jsonrepo/backends/dynamodb.py

@@ -70,6 +70,9 @@ def history(self, key, _from='-', _to='+', _desc=True):
         return []
 
     def latest(self, key):
+        self.logger.debug('Storage - get latest for {}'.format(
+            self.prefixed(key)
+        ))
         response = self.dynamodb_server.query(
             KeyConditionExpression=Key(self._key)
             .eq(self.prefixed(key)),

jsonrepo/backends/memory.py

@@ -68,6 +68,9 @@ def history(self, key, _from='-', _to='+', _desc=True):
         return [self.get(key, kid) for kid in res]
 
     def latest(self, key):
+        self.logger.debug('Storage - get latest for {}'.format(
+            self.prefixed(key)
+        ))
         if self.prefixed(key) not in self.cache:
             return None
         if len(self.cache[self.prefixed(key)]) == 0:

jsonrepo/backends/redis.py

@@ -72,6 +72,9 @@ def history(self, key, _from='-', _to='+', _desc=True):
         return res
 
     def latest(self, key):
+        self.logger.debug('Storage - get latest for {}'.format(
+            self.prefixed(key)
+        ))
         res = self.redis_server.zrevrangebylex(
             self.prefixed(key),
             '+', '-',

jsonrepo/record.py

@@ -55,6 +55,8 @@ def from_json(cls, json_dump):
         How to get a context from a json dump
         """
         context = cls()
+        if json_dump is None:
+            return None
         ctxt = json.loads(json_dump)
         for k in ctxt:
             context[k] = ctxt[k]
@@ -73,6 +75,8 @@ class NamedtupleRecord(Record):
     """
     @classmethod
     def from_json(cls, json_dump):
+        if json_dump is None:
+            return None
         kwargs = json.loads(json_dump)
         return cls(**kwargs)
 

jsonrepo/repository.py

@@ -4,11 +4,14 @@
 Author:   Romary Dupuis <romary@me.com>
 Copyright (C) 2017 Romary Dupuis
 """
+from six import add_metaclass
+from singleton import Singleton
 from loggingmixin import LoggingMixin
 from jsonrepo.mixin import StorageMixin
 from jsonrepo.record import Record
 
 
+@add_metaclass(Singleton)
 class Repository(StorageMixin, LoggingMixin):
     """
     Definition of a repository
@@ -41,13 +44,13 @@ def save(self, key, sort_key, _object):
 
     def history(self, key, _from='-', _to='+', _desc=True):
         """
-        Saves a context object
+        Retrives a list of records according to a datetime range
         """
         return [self.klass.from_json(_object)
                 for _object in self.storage.history(key, _from, _to, _desc)]
 
     def latest(self, key):
         """
-        Saves a context object
+        Get the most recent record for a specific key
         """
         return self.klass.from_json(self.storage.latest(key))

tests/tests.py

@@ -46,8 +46,8 @@ def test_singleton(self):
         """
         repo1 = MyRepository()
         repo2 = MyRepository()
-        self.assertEqual(repo1.storage, repo2.storage)
-        self.assertEqual(id(repo1.storage), id(repo2.storage))
+        self.assertEqual(repo1, repo2)
+        self.assertEqual(id(repo1), id(repo2))
 
     def test_save_record(self):
         """