rados.py: remove Rados.__del__(); it just causes problems

PendingReleaseNotes

@@ -28,3 +28,8 @@ v0.90
 
 * The 'rados create <objectname> [category]' optional category argument is no
   longer supported or recognized.
+
+* rados.py's Rados class no longer has a __del__ method; it was causing
+  problems on interpreter shutdown and use of threads.  If your code has
+  Rados objects with limited lifetimes and you're concerned about locked
+  resources, call Rados.shutdown() explicitly.

src/ceph.in

@@ -877,4 +877,8 @@ def main():
     return 0
 
 if __name__ == '__main__':
-    sys.exit(main())
+    retval = main()
+    # shutdown explicitly; Rados() does not
+    if cluster_handle:
+        cluster_handle.shutdown()
+    sys.exit(retval)

src/pybind/rados.py

@@ -259,7 +259,8 @@ def __init__(self, rados_id=None, name=None, clustername=None,
 
     def shutdown(self):
         """
-        Disconnects from the cluster.
+        Disconnects from the cluster.  Call this explicitly when a
+        Rados.connect()ed object is no longer used.
         """
         if (self.__dict__.has_key("state") and self.state != "shutdown"):
             run_in_thread(self.librados.rados_shutdown, (self.cluster,))
@@ -273,9 +274,6 @@ def __exit__(self, type_, value, traceback):
         self.shutdown()
         return False
 
-    def __del__(self):
-        self.shutdown()
-
     def version(self):
         """
         Get the version number of the ``librados`` C library.
@@ -424,7 +422,7 @@ def ping_monitor(self, mon_id):
 
     def connect(self, timeout=0):
         """
-        Connect to the cluster.
+        Connect to the cluster.  Use shutdown() to release resources.
         """
         self.require_state("configuring")
         ret = run_in_thread(self.librados.rados_connect, (self.cluster,),