Refactor few bits

src/riak_governor_ensemble_master.erl

@@ -98,18 +98,13 @@ ensure_ensemble_started([_]) ->
     % do not create an ensemble for group of one
     ok;
 ensure_ensemble_started(Nodes) ->
-    ShouldStart    = ordsets:is_element(node(), Nodes),
-    AlreadyStarted = ensemble_started(Nodes),
-    case ShouldStart andalso not AlreadyStarted of
-        true ->
-            case start_ensemble(Nodes) of
-                ok ->
-                    add_ensemble_to_index(Nodes),
-                    ok;
-                Other -> Other
-            end;
-        false -> ok
-    end.
+    Fns = [
+           fun() -> is_local_ensemble(Nodes) end,
+           fun() -> ensemble_started(Nodes) end,
+           fun() -> start_ensemble(Nodes) end,
+           fun() -> add_ensemble_to_index(Nodes) end
+          ],
+    riak_governor_util:whileok(Fns).
 
 %% Determine the set of ensembles. Currently, there is one ensemble of each
 %% unique set of preflist owning nodes.
@@ -130,6 +125,9 @@ add_ensemble_to_index(Nodes) ->
 ensemble_started(Nodes) ->
     ets:lookup(?MODULE, Nodes) =/= [].
 
+is_local_ensemble(Nodes) ->
+    ordsets:is_element(node(), Nodes).
+
 start_ensemble(Nodes) ->
     EnsembleName = riak_governor_util:ensemble_name(Nodes),
     Peers = lists:map(fun(Node) -> {EnsembleName, Node} end, Nodes),

src/riak_governor_util.erl

@@ -5,6 +5,7 @@
 -export([get_ensemble_size/0, get_ensemble_provider/0, ensemble_name/1]).
 -export([get_primary_apl/1]).
 -export([get_cluster_nodes/0]).
+-export([whileok/1]).
 
 get_ensemble_size() ->
     riak_governor:get_env(ensemble_size, ?DEFAULT_ENSEMBLE_SIZE).
@@ -25,3 +26,17 @@ get_primary_apl(DocIdx) ->
 get_cluster_nodes() ->
     {ok, Ring} = riak_core_ring_manager:get_raw_ring(),
     lists:usort(riak_core_ring:all_members(Ring)).
+
+whileok([]) ->
+    ok;
+whileok([Fn|Fns]) ->
+    case Fn() of
+        ok ->
+            whileok(Fns);
+        true ->
+            whileok(Fns);
+        {ok, _} ->
+            whileok(Fns);
+        Other ->
+            Other
+    end.