Refactor rabbit_recovery_terms startup

Rename rabbit_queue_index:{recover => start}/1.
Rename rabbit_shutdown_terms{recover => start}/0.
Stop handling supervisor child-start errors explicitly.
Add {rabbit_recovery_terms, rabbit_queue_index}:stop/0 variants.
Introduce a `stop’ code path from BQ:stop/0 to qi:stop/0.

3 files changed, 16 insertions, 14 deletions

diff --git a/src/rabbit_queue_index.erl b/src/rabbit_queue_index.erl
index 8db6717d76..b5a316f0cf 100644
--- a/src/rabbit_queue_index.erl
+++ b/src/rabbit_queue_index.erl
@@ -19,7 +19,7 @@
 -export([init/2, recover/5,
          terminate/2, delete_and_terminate/1,
          publish/5, deliver/2, ack/2, sync/1, needs_sync/1, flush/1,
-         read/3, next_segment_boundary/1, bounds/1, recover/1]).
+         read/3, next_segment_boundary/1, bounds/1, start/1, stop/0]).
 
 -export([add_queue_ttl/0, avoid_zeroes/0]).
 
@@ -217,7 +217,7 @@
 -spec(next_segment_boundary/1 :: (seq_id()) -> seq_id()).
 -spec(bounds/1 :: (qistate()) ->
                        {non_neg_integer(), non_neg_integer(), qistate()}).
--spec(recover/1 :: ([rabbit_amqqueue:name()]) -> {[[any()]], {walker(A), A}}).
+-spec(start/1 :: ([rabbit_amqqueue:name()]) -> {[[any()]], {walker(A), A}}).
 
 -spec(add_queue_ttl/0 :: () -> 'ok').
 
@@ -342,8 +342,8 @@ bounds(State = #qistate { segments = Segments }) ->
         end,
     {LowSeqId, NextSeqId, State}.
 
-recover(DurableQueueNames) ->
-    ok = rabbit_recovery_terms:recover(),
+start(DurableQueueNames) ->
+    ok = rabbit_recovery_terms:start(),
     {DurableTerms, DurableDirectories} =
         lists:foldl(
           fun(QName, {RecoveryTerms, ValidDirectories}) ->
@@ -369,6 +369,8 @@ recover(DurableQueueNames) ->
     OrderedTerms = lists:reverse(DurableTerms),
     {OrderedTerms, {fun queue_index_walker/1, {start, DurableQueueNames}}}.
 
+stop() -> rabbit_recovery_terms:stop().
+
 all_queue_directory_names(Dir) ->
     case rabbit_file:list_dir(Dir) of
         {ok, Entries}   -> [ Entry || Entry <- Entries,
diff --git a/src/rabbit_recovery_terms.erl b/src/rabbit_recovery_terms.erl
index 6e2a4a3d53..24f2edb2f6 100644
--- a/src/rabbit_recovery_terms.erl
+++ b/src/rabbit_recovery_terms.erl
@@ -21,7 +21,7 @@
 
 -behaviour(gen_server).
 
--export([recover/0, store/2, read/1, clear/0]).
+-export([start/0, stop/0, store/2, read/1, clear/0]).
 
 -export([upgrade_recovery_terms/0, start_link/0]).
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
@@ -33,7 +33,8 @@
 
 -ifdef(use_specs).
 
--spec(recover() -> 'ok').
+-spec(start() -> rabbit_types:ok_or_error(term())).
+-spec(stop() -> rabbit_types:ok_or_error(term())).
 -spec(store(file:filename(), term()) -> rabbit_types:ok_or_error(term())).
 -spec(read(file:filename()) -> rabbit_types:ok_or_error2(term(), not_found)).
 -spec(clear() -> 'ok').
@@ -44,12 +45,9 @@
 
 -define(SERVER, ?MODULE).
 
-recover() ->
-    case rabbit_sup:start_child(?MODULE) of
-        ok                            -> ok;
-        {error, {already_started, _}} -> ok;
-        {error, _}=Err                -> Err
-    end.
+start() -> rabbit_sup:start_child(?MODULE).
+
+stop() -> rabbit_sup:stop_child(?MODULE).
 
 store(DirBaseName, Terms) -> dets:insert(?MODULE, {DirBaseName, Terms}).
 
diff --git a/src/rabbit_variable_queue.erl b/src/rabbit_variable_queue.erl
index a5dc5df498..8711d1393a 100644
--- a/src/rabbit_variable_queue.erl
+++ b/src/rabbit_variable_queue.erl
@@ -389,7 +389,7 @@
 %%----------------------------------------------------------------------------
 
 start(DurableQueues) ->
-    {AllTerms, StartFunState} = rabbit_queue_index:recover(DurableQueues),
+    {AllTerms, StartFunState} = rabbit_queue_index:start(DurableQueues),
     start_msg_store(
       [Ref || Terms <- AllTerms,
               Terms /= non_clean_shutdown,
@@ -400,7 +400,9 @@ start(DurableQueues) ->
       StartFunState),
     {ok, AllTerms}.
 
-stop() -> stop_msg_store().
+stop() ->
+    ok = stop_msg_store(),
+    ok = rabbit_queue_index:stop().
 
 start_msg_store(Refs, StartFunState) ->
     ok = rabbit_sup:start_child(?TRANSIENT_MSG_STORE, rabbit_msg_store,