client: new 'cache-size' Storage option

neo/client/app.py

@@ -59,7 +59,8 @@ class Application(ThreadedApplication):
     # is unreachable.
     max_reconnection_to_master = float('inf')
 
-    def __init__(self, master_nodes, name, compress=True, **kw):
+    def __init__(self, master_nodes, name, compress=True, cache_size=None,
+                 **kw):
         super(Application, self).__init__(parseMasterList(master_nodes),
                                           name, **kw)
         # Internal Attributes common to all thread
@@ -69,7 +70,8 @@ class Application(ThreadedApplication):
         self.trying_master_node = None
 
         # no self-assigned UUID, primary master will supply us one
-        self._cache = ClientCache()
+        self._cache = ClientCache() if cache_size is None else \
+                      ClientCache(max_size=cache_size)
         self._loading_oid = None
         self.new_oid_list = ()
         self.last_oid = '\0' * 8

neo/client/component.xml

@@ -32,6 +32,13 @@
         Log debugging information to specified SQLite DB.
       </description>
     </key>
+    <key name="cache-size" datatype="byte-size" default="20MB">
+      <description>
+         Storage cache size in bytes. Records are cached uncompressed.
+         Optional ``KB``, ``MB`` or ``GB`` suffixes can (and usually are)
+         used to specify units other than bytes.
+      </description>
+    </key>
     <key name="dynamic_master_list" datatype="existing-dirpath">
       <description>
         The file designated by this option contains an updated list of master