Support updating decorators correctly when plugins start and stop.

1 files changed, 23 insertions, 1 deletions

diff --git a/src/rabbit_exchange_decorator.erl b/src/rabbit_exchange_decorator.erl
index 2f056b1b..900f9c32 100644
--- a/src/rabbit_exchange_decorator.erl
+++ b/src/rabbit_exchange_decorator.erl
@@ -18,7 +18,7 @@
 
 -include("rabbit.hrl").
 
--export([select/2, set/1]).
+-export([select/2, set/1, register/2, unregister/1]).
 
 %% This is like an exchange type except that:
 %%
@@ -104,3 +104,25 @@ list() -> [M || {_, M} <- rabbit_registry:lookup_all(exchange_decorator)].
 
 cons_if_eq(Select,  Select, Item,  List) -> [Item | List];
 cons_if_eq(_Select, _Other, _Item, List) -> List.
+
+register(TypeName, ModuleName) ->
+    rabbit_registry:register(exchange_decorator, TypeName, ModuleName),
+    [maybe_recover(X) || X <- rabbit_exchange:list()],
+    ok.
+
+unregister(TypeName) ->
+    rabbit_registry:unregister(exchange_decorator, TypeName),
+    [maybe_recover(X) || X <- rabbit_exchange:list()],
+    ok.
+
+maybe_recover(X = #exchange{name       = Name,
+                            decorators = Decs}) ->
+    #exchange{decorators = Decs1} = set(X),
+    Old = lists:sort(select(all, Decs)),
+    New = lists:sort(select(all, Decs1)),
+    case New of
+        Old -> ok;
+        _   -> %% TODO create a tx here for non-federation decorators
+               [M:create(none, X) || M <- New -- Old],
+               rabbit_exchange:update_decorators(Name)
+    end.