more detailed report for mem3:states()

1 files changed, 12 insertions, 6 deletions

diff --git a/src/mem3.erl b/src/mem3.erl
index 29140471..55a8a541 100644
--- a/src/mem3.erl
+++ b/src/mem3.erl
@@ -77,14 +77,20 @@ state() ->
     gen_server:call(?SERVER, state).
 
 
--spec states() -> {ok, [mem_state()]}.
+%% @doc Detailed report of cluster-wide membership state.  Queries the state
+%%      on all member nodes and builds a dictionary with unique states as the
+%%      key and the nodes holding that state as the value.  Also reports member
+%%      nodes which fail to respond and nodes which are connected but are not
+%%      cluster members.  Useful for debugging.
+-spec states() -> [{mem_state() | bad_nodes | non_member_nodes, [node()]}].
 states() ->
     {ok, Nodes} = mem3:nodes(),
-    case rpc:multicall(Nodes, ?MODULE, state, []) of
-    {States, []} -> {ok, lists:map(fun({ok,S}) -> S end, States)};
-    {Good, Bad}  -> {error, {[{good,Good},{bad,Bad}]}}
-    end.
-
+    AllNodes = [node()|erlang:nodes()],
+    {Replies, BadNodes} = gen_server:multi_call(Nodes, ?SERVER, state),
+    Dict = lists:foldl(fun({Node, {ok,State}}, D) ->
+        orddict:append(State, Node, D)
+    end, orddict:new(), Replies),
+    [{non_member_nodes, AllNodes -- Nodes}, {bad_nodes, BadNodes} | Dict].
 
 -spec start_gossip() -> ok.
 start_gossip() ->