Adding helpful utilities for diagnosing and fixing rings

ebin/riak_core.app

@@ -31,6 +31,7 @@
              riak_core_ring_events,
              riak_core_ring_handler,
              riak_core_ring_manager,
+             riak_core_ring_util,
              riak_core_sup,
              riak_core_test_util,
              riak_core_util,

src/riak_core_ring_util.erl

@@ -0,0 +1,57 @@
+%% -------------------------------------------------------------------
+%%
+%% riak_core: Core Riak Application
+%%
+%% Copyright (c) 2007-2010 Basho Technologies, Inc.  All Rights Reserved.
+%%
+%% This file is provided to you under the Apache License,
+%% Version 2.0 (the "License"); you may not use this file
+%% except in compliance with the License.  You may obtain
+%% a copy of the License at
+%%
+%%   http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing,
+%% software distributed under the License is distributed on an
+%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+%% KIND, either express or implied.  See the License for the
+%% specific language governing permissions and limitations
+%% under the License.
+%%
+%% -------------------------------------------------------------------
+-module(riak_core_ring_util).
+
+-export([assign/2,
+         check_ring/0,
+         check_ring/1]).
+
+%% @doc Forcibly assign a partition to a specific node
+assign(Partition, ToNode) ->
+    F = fun(Ring, _) ->
+                {new_ring, riak_core_ring:transfer_node(Partition, ToNode, Ring)}
+        end,
+    {ok, _} = riak_core_ring_manager:ring_trans(F, undefined),
+    %% TODO: ring_trans really should kick off a write of the ringfile, but
+    %% currently doesn't. Do so manually.
+    riak_core_ring_manager:do_write_ringfile(),
+    ok.
+
+%% @doc Check the local ring for any preflists that do not satisfy n_val
+check_ring() ->
+    {ok, R} = riak_core_ring_manager:get_my_ring(),
+    check_ring(R).
+
+%% @doc Check a ring for any preflists that do not satisfy n_val
+check_ring(Ring) ->
+    {ok, Props} = application:get_env(riak_core, default_bucket_props),
+    {n_val, Nval} = lists:keyfind(n_val, 1, Props),
+    Preflists = riak_core_ring:all_preflists(Ring, Nval),
+    lists:foldl(fun(PL,Acc) ->
+                        PLNodes = lists:usort([Node || {_,Node} <- PL]),
+                        case length(PLNodes) of
+                            Nval ->
+                                Acc;
+                            _ ->
+                                ordsets:add_element(PL, Acc)
+                        end
+                end, [], Preflists).