Merge pull request #8749 from rabbitmq/reset-feature-flags-registry-on-boot

rabbit_feature_flags: Reset the registry before the boot-time init

Author: dumbbell

deps/rabbit/src/rabbit_deprecated_features.erl

@@ -497,6 +497,11 @@ is_permitted_in_configuration(FeatureName, Default) ->
     Settings = application:get_env(rabbit, permit_deprecated_features, #{}),
     case maps:get(FeatureName, Settings, undefined) of
         undefined ->
+            ?LOG_DEBUG(
+               "Deprecated features: `~ts`: `permit_deprecated_features` "
+               "map unset in configuration, using default",
+               [FeatureName],
+               #{domain => ?RMQLOG_DOMAIN_FEAT_FLAGS}),
             Default;
         Default ->
             PermittedStr = case Default of

deps/rabbit/src/rabbit_ff_registry_factory.erl

@@ -18,7 +18,8 @@
          initialize_registry/1,
          initialize_registry/3,
          acquire_state_change_lock/0,
-         release_state_change_lock/0]).
+         release_state_change_lock/0,
+         reset_registry/0]).
 
 -ifdef(TEST).
 -export([registry_loading_lock/0,
@@ -784,3 +785,15 @@ do_purge_old_registry(Mod) ->
         true  -> ok;
         false -> do_purge_old_registry(Mod)
     end.
+
+-spec reset_registry() -> ok.
+
+reset_registry() ->
+    ?LOG_DEBUG(
+       "Feature flags: resetting loaded registry",
+       [],
+       #{domain => ?RMQLOG_DOMAIN_FEAT_FLAGS}),
+    _ = code:purge(rabbit_ff_registry),
+    _ = code:delete(rabbit_ff_registry),
+    ?assertNot(rabbit_ff_registry:is_registry_initialized()),
+    ok.

deps/rabbit/src/rabbit_prelaunch_feature_flags.erl

@@ -19,6 +19,13 @@ setup(#{feature_flags_file := FFFile}) ->
        #{domain => ?RMQLOG_DOMAIN_PRELAUNCH}),
     case filelib:ensure_dir(FFFile) of
         ok ->
+            %% On boot, we know that there should be no registry loaded at
+            %% first. There could be a loaded registry around during a
+            %% stop_app/start_app, so reset it here. This ensures that e.g.
+            %% any change to the configuration file w.r.t. deprecated features
+            %% are taken into account.
+            rabbit_ff_registry_factory:reset_registry(),
+
             ?LOG_DEBUG(
                "Initializing feature flags registry", [],
                #{domain => ?RMQLOG_DOMAIN_PRELAUNCH}),