fix(ds): tidy up few typespecs

apps/emqx/src/emqx_persistent_session_ds.erl

@@ -533,7 +533,7 @@ replay_streams(Session0 = #{replay := []}, _ClientInfo) ->
     %% mechanisms to replay them:
     pull_now(Session).
 
--spec replay_batch(stream_state(), session(), clientinfo()) -> session().
+-spec replay_batch(stream_state(), session(), clientinfo()) -> session() | emqx_ds:error(_).
 replay_batch(Srs0, Session0, ClientInfo) ->
     #srs{batch_size = BatchSize} = Srs0,
     case enqueue_batch(true, BatchSize, Srs0, Session0, ClientInfo) of

apps/emqx/src/emqx_rpc.erl

@@ -35,6 +35,7 @@
 
 -export_type([
     badrpc/0,
+    call_result/1,
     call_result/0,
     cast_result/0,
     multicall_result/1,

apps/emqx_durable_storage/src/emqx_ds_replication_layer.erl

@@ -171,13 +171,12 @@ drop_db(DB) ->
 -spec store_batch(emqx_ds:db(), [emqx_types:message(), ...], emqx_ds:message_store_opts()) ->
     emqx_ds:store_batch_result().
 store_batch(DB, Messages, Opts) ->
-    case emqx_ds_replication_layer_egress:store_batch(DB, Messages, Opts) of
+    try emqx_ds_replication_layer_egress:store_batch(DB, Messages, Opts) of
         ok ->
-            ok;
+            ok
-        Error = {error, _, _} ->
+    catch
-            Error;
+        error:{Reason, _Call} when Reason == timeout; Reason == noproc ->
-        RPCError = {badrpc, _} ->
+            {error, recoverable, Reason}
-            {error, recoverable, RPCError}
     end.
 
 -spec get_streams(emqx_ds:db(), emqx_ds:topic_filter(), emqx_ds:time()) ->

apps/emqx_durable_storage/src/proto/emqx_ds_proto_v4.erl

@@ -64,7 +64,7 @@ get_streams(Node, DB, Shard, TopicFilter, Time) ->
     emqx_ds:topic_filter(),
     emqx_ds:time()
 ) ->
-    {ok, emqx_ds_storage_layer:iterator()} | {error, _}.
+    emqx_ds:make_iterator_result().
 make_iterator(Node, DB, Shard, Stream, TopicFilter, StartTime) ->
     erpc:call(Node, emqx_ds_replication_layer, do_make_iterator_v2, [
         DB, Shard, Stream, TopicFilter, StartTime
@@ -77,9 +77,7 @@ make_iterator(Node, DB, Shard, Stream, TopicFilter, StartTime) ->
     emqx_ds_storage_layer:iterator(),
     pos_integer()
 ) ->
-    {ok, emqx_ds_storage_layer:iterator(), [{emqx_ds:message_key(), [emqx_types:message()]}]}
+    emqx_rpc:call_result(emqx_ds:next_result()).
-    | {ok, end_of_stream}
-    | {error, _}.
 next(Node, DB, Shard, Iter, BatchSize) ->
     emqx_rpc:call(Shard, Node, emqx_ds_replication_layer, do_next_v1, [DB, Shard, Iter, BatchSize]).
 
@@ -103,7 +101,7 @@ store_batch(Node, DB, Shard, Batch, Options) ->
     emqx_ds_storage_layer:iterator(),
     emqx_ds:message_key()
 ) ->
-    {ok, emqx_ds_storage_layer:iterator()} | {error, _}.
+    emqx_ds:make_iterator_result().
 update_iterator(Node, DB, Shard, OldIter, DSKey) ->
     erpc:call(Node, emqx_ds_replication_layer, do_update_iterator_v2, [
         DB, Shard, OldIter, DSKey