fix(ds): Fix code review remark

apps/emqx_durable_storage/src/emqx_ds_builtin_db_sup.erl

@@ -33,6 +33,12 @@
 ]).
 -export([which_dbs/0, which_shards/1]).
 
+%% Debug:
+-export([
+    get_egress_workers/1,
+    get_shard_workers/1
+]).
+
 %% behaviour callbacks:
 -export([init/1]).
 
@@ -111,6 +117,28 @@ which_dbs() ->
     Key = {n, l, #?db_sup{_ = '_', db = '$1'}},
     gproc:select({local, names}, [{{Key, '_', '_'}, [], ['$1']}]).
 
+%% @doc Get pids of all local egress servers for the given DB.
+-spec get_egress_workers(emqx_ds:db()) -> #{_Shard => pid()}.
+get_egress_workers(DB) ->
+    Children = supervisor:which_children(?via(#?egress_sup{db = DB})),
+    L = [{Shard, Child} || {Shard, Child, _, _} <- Children, is_pid(Child)],
+    maps:from_list(L).
+
+%% @doc Get pids of all local shard servers for the given DB.
+-spec get_shard_workers(emqx_ds:db()) -> #{_Shard => pid()}.
+get_shard_workers(DB) ->
+    Shards = supervisor:which_children(?via(#?shards_sup{db = DB})),
+    L = lists:flatmap(
+        fun
+            ({_Shard, Sup, _, _}) when is_pid(Sup) ->
+                [{Id, Pid} || {Id, Pid, _, _} <- supervisor:which_children(Sup), is_pid(Pid)];
+            (_) ->
+                []
+        end,
+        Shards
+    ),
+    maps:from_list(L).
+
 %%================================================================================
 %% behaviour callbacks
 %%================================================================================

apps/emqx_durable_storage/src/emqx_ds_replication_layer_egress.erl

@@ -129,12 +129,20 @@ init([DB, Shard]) ->
     },
     {ok, S}.
 
-format_status(#s{db = DB, shard = Shard, queue = Q}) ->
-    #{
-        db => DB,
-        shard => Shard,
-        queue => queue:len(Q)
-    }.
+format_status(Status) ->
+    maps:map(
+        fun
+            (state, #s{db = DB, shard = Shard, queue = Q}) ->
+                #{
+                    db => DB,
+                    shard => Shard,
+                    queue => queue:len(Q)
+                };
+            (_, Val) ->
+                Val
+        end,
+        Status
+    ).
 
 handle_call(
     #enqueue_req{

apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl

@@ -589,23 +589,16 @@ init({ShardId, Options}) ->
     commit_metadata(S),
     {ok, S}.
 
-format_status(#s{shard_id = ShardId, db = DB, cf_refs = CFRefs, schema = Schema, shard = Shard}) ->
-    #{
-        id => ShardId,
-        db => DB,
-        cf_refs => CFRefs,
-        schema => Schema,
-        shard =>
-            maps:map(
-                fun
-                    (?GEN_KEY(_), _Schema) ->
-                        '...';
-                    (_K, Val) ->
-                        Val
-                end,
-                Shard
-            )
-    }.
+format_status(Status) ->
+    maps:map(
+        fun
+            (state, State) ->
+                format_state(State);
+            (_, Val) ->
+                Val
+        end,
+        Status
+    ).
 
 handle_call(#call_update_config{since = Since, options = Options}, _From, S0) ->
     case handle_update_config(S0, Since, Options) of
@@ -791,7 +784,7 @@ handle_drop_generation(S0, GenId) ->
                     EC => Err,
                     stacktrace => Stack,
                     generation => GenId,
-                    s => format_status(S0)
+                    s => format_state(S0)
                 }
             )
     end,
@@ -994,6 +987,24 @@ generations_since(Shard, Since) ->
         Schema
     ).
 
+format_state(#s{shard_id = ShardId, db = DB, cf_refs = CFRefs, schema = Schema, shard = Shard}) ->
+    #{
+        id => ShardId,
+        db => DB,
+        cf_refs => CFRefs,
+        schema => Schema,
+        shard =>
+            maps:map(
+                fun
+                    (?GEN_KEY(_), _Schema) ->
+                        '...';
+                    (_K, Val) ->
+                        Val
+                end,
+                Shard
+            )
+    }.
+
 -define(PERSISTENT_TERM(SHARD), {emqx_ds_storage_layer, SHARD}).
 
 -spec get_schema_runtime(shard_id()) -> shard().