Make decorators field in exchange and queue transient, i.e. we recalcualte it on recovery in case plugins have changed. Also document a bit more clearly what the lifecycle is of the different fields in these records since that area is becoming confusing.

4 files changed, 45 insertions, 31 deletions

diff --git a/include/rabbit.hrl b/include/rabbit.hrl
index 5ac3197e..a0e96d87 100644
--- a/include/rabbit.hrl
+++ b/include/rabbit.hrl
@@ -39,13 +39,24 @@
 
 -record(resource, {virtual_host, kind, name}).
 
--record(exchange, {name, type, durable, auto_delete, internal, arguments,
-                   scratches, policy, decorators}).
--record(exchange_serial, {name, next}).
+%% fields described as 'transient' here are cleared when writing to
+%% rabbit_durable_<thing>
+-record(exchange, {
+          name, type, durable, auto_delete, internal, arguments, %% immutable
+          scratches,    %% durable, explicitly updated via update_scratch/3
+          policy,       %% durable, implicitly updated when policy changes
+          decorators}). %% transient, recalculated in store/1 (i.e. recovery)
+
+-record(amqqueue, {
+          name, durable, auto_delete, exclusive_owner = none, %% immutable
+          arguments,                   %% immutable
+          pid,                         %% durable (just so we know home node)
+          slave_pids, sync_slave_pids, %% transient
+          policy,                      %% durable, implicit update as above
+          gm_pids,                     %% transient
+          decorators}).                %% transient, recalculated as above
 
--record(amqqueue, {name, durable, auto_delete, exclusive_owner = none,
-                   arguments, pid, slave_pids, sync_slave_pids, policy,
-                   gm_pids, decorators}).
+-record(exchange_serial, {name, next}).
 
 %% mnesia doesn't like unary records, so we add a dummy 'value' field
 -record(route, {binding, value = const}).
diff --git a/src/rabbit_amqqueue.erl b/src/rabbit_amqqueue.erl
index 1aba7ecb..8bc0cab6 100644
--- a/src/rabbit_amqqueue.erl
+++ b/src/rabbit_amqqueue.erl
@@ -254,15 +254,16 @@ declare(QueueName, Durable, AutoDelete, Args, Owner) ->
 %% effect) this might not be possible to satisfy.
 declare(QueueName, Durable, AutoDelete, Args, Owner, Node) ->
     ok = check_declare_arguments(QueueName, Args),
-    Q = rabbit_policy:set(#amqqueue{name            = QueueName,
-                                    durable         = Durable,
-                                    auto_delete     = AutoDelete,
-                                    arguments       = Args,
-                                    exclusive_owner = Owner,
-                                    pid             = none,
-                                    slave_pids      = [],
-                                    sync_slave_pids = [],
-                                    gm_pids         = []}),
+    Q = rabbit_queue_decorator:set(
+          rabbit_policy:set(#amqqueue{name            = QueueName,
+                                      durable         = Durable,
+                                      auto_delete     = AutoDelete,
+                                      arguments       = Args,
+                                      exclusive_owner = Owner,
+                                      pid             = none,
+                                      slave_pids      = [],
+                                      sync_slave_pids = [],
+                                      gm_pids         = []})),
     Node = rabbit_mirror_queue_misc:initial_queue_node(Q, Node),
     gen_server2:call(start_queue_process(Node, Q), {init, new}, infinity).
 
@@ -308,12 +309,14 @@ store_queue(Q = #amqqueue{durable = true}) ->
     ok = mnesia:write(rabbit_durable_queue,
                       Q#amqqueue{slave_pids      = [],
                                  sync_slave_pids = [],
-                                 gm_pids         = []}, write),
-    ok = mnesia:write(rabbit_queue, Q, write),
-    ok;
+                                 gm_pids         = [],
+                                 decorators      = []}, write),
+    store_queue0(Q);
 store_queue(Q = #amqqueue{durable = false}) ->
-    ok = mnesia:write(rabbit_queue, Q, write),
-    ok.
+    store_queue0(Q).
+
+store_queue0(Q) ->
+    ok = mnesia:write(rabbit_queue, rabbit_queue_decorator:set(Q), write).
 
 policy_changed(Q1 = #amqqueue{decorators = Decorators1},
                Q2 = #amqqueue{decorators = Decorators2}) ->
diff --git a/src/rabbit_exchange.erl b/src/rabbit_exchange.erl
index 4d4a2a58..f1b2d694 100644
--- a/src/rabbit_exchange.erl
+++ b/src/rabbit_exchange.erl
@@ -158,12 +158,13 @@ serial(#exchange{name = XName} = X) ->
     end.
 
 declare(XName, Type, Durable, AutoDelete, Internal, Args) ->
-    X = rabbit_policy:set(#exchange{name        = XName,
-                                    type        = Type,
-                                    durable     = Durable,
-                                    auto_delete = AutoDelete,
-                                    internal    = Internal,
-                                    arguments   = Args}),
+    X = rabbit_exchange_decorator:set(
+          rabbit_policy:set(#exchange{name        = XName,
+                                      type        = Type,
+                                      durable     = Durable,
+                                      auto_delete = AutoDelete,
+                                      internal    = Internal,
+                                      arguments   = Args})),
     XT = type_to_module(Type),
     %% We want to upset things if it isn't ok
     ok = XT:validate(X),
@@ -195,7 +196,8 @@ declare(XName, Type, Durable, AutoDelete, Internal, Args) ->
 map_create_tx(true)  -> transaction;
 map_create_tx(false) -> none.
 
-store(X) -> ok = mnesia:write(rabbit_exchange, X, write).
+store(X) -> ok = mnesia:write(
+                   rabbit_exchange, rabbit_exchange_decorator:set(X), write).
 
 %% Used with binaries sent over the wire; the type may not exist.
 check_type(TypeBin) ->
diff --git a/src/rabbit_policy.erl b/src/rabbit_policy.erl
index 0a69fb32..5a1e5452 100644
--- a/src/rabbit_policy.erl
+++ b/src/rabbit_policy.erl
@@ -46,10 +46,8 @@ name(#exchange{policy = Policy}) -> name0(Policy).
 name0(undefined) -> none;
 name0(Policy)    -> pget(name, Policy).
 
-set(Q = #amqqueue{name = Name}) -> rabbit_queue_decorator:set(
-                                     Q#amqqueue{policy = set0(Name)});
-set(X = #exchange{name = Name}) -> rabbit_exchange_decorator:set(
-                                     X#exchange{policy = set0(Name)}).
+set(Q = #amqqueue{name = Name}) -> Q#amqqueue{policy = set0(Name)};
+set(X = #exchange{name = Name}) -> X#exchange{policy = set0(Name)}.
 
 set0(Name = #resource{virtual_host = VHost}) -> match(Name, list(VHost)).