Add a policy for this thing

2 files changed, 28 insertions, 13 deletions

diff --git a/src/rabbit_mirror_queue_master.erl b/src/rabbit_mirror_queue_master.erl
index e8819bfa9c..792cebd129 100644
--- a/src/rabbit_mirror_queue_master.erl
+++ b/src/rabbit_mirror_queue_master.erl
@@ -176,13 +176,14 @@ terminate(Reason,
     %% Backing queue termination. The queue is going down but
     %% shouldn't be deleted. Most likely safe shutdown of this
     %% node.
-    {ok, #amqqueue{sync_slave_pids = SSPids}} = rabbit_amqqueue:lookup(QName),
-    %% TODO there should be a policy for this
-    case SSPids of
-        [] -> %% Remove the whole queue to avoid data loss
-              stop_all_slaves(Reason, nodelete, State);
-        _  -> %% Just let some other slave take over.
-              ok
+    {ok, Q = #amqqueue{sync_slave_pids = SSPids}} =
+        rabbit_amqqueue:lookup(QName),
+    case SSPids =:= [] andalso
+        rabbit_policy:get(<<"ha-promote-on-shutdown">>, Q) =/= <<"always">> of
+        true  -> %% Remove the whole queue to avoid data loss
+                 stop_all_slaves(Reason, State);
+        false -> %% Just let some other slave take over.
+                 ok
     end,
     State #state { backing_queue_state = BQ:terminate(Reason, BQS) }.
 
diff --git a/src/rabbit_mirror_queue_misc.erl b/src/rabbit_mirror_queue_misc.erl
index b0f092a9a0..8ba6968c26 100644
--- a/src/rabbit_mirror_queue_misc.erl
+++ b/src/rabbit_mirror_queue_misc.erl
@@ -374,16 +374,21 @@ validate_policy(KeyList) ->
     Mode = proplists:get_value(<<"ha-mode">>, KeyList, none),
     Params = proplists:get_value(<<"ha-params">>, KeyList, none),
     SyncMode = proplists:get_value(<<"ha-sync-mode">>, KeyList, none),
-    case {Mode, Params, SyncMode} of
-        {none, none, none} ->
+    PromoteOnShutdown = proplists:get_value(
+                          <<"ha-promote-on-shutdown">>, KeyList, none),
+    case {Mode, Params, SyncMode, PromoteOnShutdown} of
+        {none, none, none, none} ->
             ok;
-        {none, _, _} ->
-            {error, "ha-mode must be specified to specify ha-params or "
-             "ha-sync-mode", []};
+        {none, _, _, _} ->
+            {error, "ha-mode must be specified to specify ha-params, "
+             "ha-sync-mode or ha-promote-on-shutdown", []};
         _ ->
             case module(Mode) of
                 {ok, M} -> case M:validate_policy(Params) of
-                               ok -> validate_sync_mode(SyncMode);
+                               ok -> case validate_sync_mode(SyncMode) of
+                                         ok -> validate_pos(PromoteOnShutdown);
+                                         E  -> E
+                                     end;
                                E  -> E
                            end;
                 _       -> {error, "~p is not a valid ha-mode value", [Mode]}
@@ -398,3 +403,12 @@ validate_sync_mode(SyncMode) ->
         Mode            -> {error, "ha-sync-mode must be \"manual\" "
                             "or \"automatic\", got ~p", [Mode]}
     end.
+
+validate_pos(PromoteOnShutdown) ->
+    case PromoteOnShutdown of
+        <<"always">>      -> ok;
+        <<"when-synced">> -> ok;
+        none              -> ok;
+        Mode              -> {error, "ha-promote-on-shutdown must be "
+                              "\"always\" or \"when-synced\", got ~p", [Mode]}
+    end.