chore(retainer): refactor types; remove hotwiring to builtin config

apps/emqx_retainer/include/emqx_retainer.hrl

@@ -13,6 +13,8 @@
 %% See the License for the specific language governing permissions and
 %% limitations under the License.
 %%--------------------------------------------------------------------
+-ifndef(EMQX_RETAINER_HRL).
+-define(EMQX_RETAINER_HRL, true).
 
 -include_lib("emqx/include/emqx.hrl").
 
@@ -22,22 +24,4 @@
 -define(TAB_INDEX_META, emqx_retainer_index_meta).
 -define(RETAINER_SHARD, emqx_retainer_shard).
 
--type topic() :: binary().
--type payload() :: binary().
--type message() :: #message{}.
-
--type context() :: #{
-    context_id := pos_integer(),
-    atom() => term()
-}.
-
--define(DELIVER_SEMAPHORE, deliver_remained_quota).
--type semaphore() :: ?DELIVER_SEMAPHORE.
--type cursor() :: undefined | term().
--type result() :: term().
-
--define(SHARED_CONTEXT_TAB, emqx_retainer_ctx).
--record(shared_context, {key :: atom(), value :: term()}).
--type shared_context_key() :: ?DELIVER_SEMAPHORE.
-
--type backend() :: emqx_retainer_storage_mnesia.
+-endif.

apps/emqx_retainer/src/emqx_retainer.erl

@@ -58,6 +58,11 @@
     code_change/3
 ]).
 
+-export_type([
+    cursor/0,
+    context/0
+]).
+
 %% exported for `emqx_telemetry'
 -export([get_basic_usage_info/0]).
 
@@ -66,12 +71,19 @@
     context := undefined | context(),
     clear_timer := undefined | reference()
 }.
+-type context() :: term().
+
+-type topic() :: emqx_types:topic().
+-type message() :: emqx_types:message().
+-type cursor() :: undefined | term().
+-type backend() :: emqx_retainer_mnesia | module().
 
 -define(DEF_MAX_PAYLOAD_SIZE, (1024 * 1024)).
 -define(DEF_EXPIRY_INTERVAL, 0).
 -define(MAX_PAYLOAD_SIZE_CONFIG_PATH, [retainer, max_payload_size]).
 
 -callback create(map()) -> context().
+-callback update(context(), map()) -> ok | need_recreate.
 -callback close(context()) -> ok.
 -callback delete_message(context(), topic()) -> ok.
 -callback store_retained(context(), message()) -> ok.
@@ -180,8 +192,7 @@ stats_fun() ->
 -spec get_basic_usage_info() -> #{retained_messages => non_neg_integer()}.
 get_basic_usage_info() ->
     try
-        RetainedMessages = gen_server:call(?MODULE, retained_count),
-        #{retained_messages => RetainedMessages}
+        #{retained_messages => retained_count()}
     catch
         _:_ ->
             #{retained_messages => 0}
@@ -319,27 +330,25 @@ update_config(true, false, State, NewConf, _) ->
 update_config(
     true,
     true,
-    #{clear_timer := ClearTimer} = State,
+    #{clear_timer := ClearTimer, context := Context} = State,
     NewConf,
     OldConf
 ) ->
     #{
         backend := #{
-            type := BackendType,
-            storage_type := StorageType
-        },
+            type := BackendType
+        } = NewBackendConfig,
         msg_clear_interval := ClearInterval
     } = NewConf,
 
     #{
         backend := #{
-            type := OldBackendType,
-            storage_type := OldStorageType
+            type := OldBackendType
         }
     } = OldConf,
     SameBackendType = BackendType =:= OldBackendType,
-    SameStorageType = StorageType =:= OldStorageType,
-    case SameBackendType andalso SameStorageType of
+    Mod = get_backend_module(),
+    case SameBackendType andalso ok =:= Mod:update(Context, NewBackendConfig) of
         true ->
             State#{
                 clear_timer := check_timer(
@@ -362,7 +371,7 @@ enable_retainer(
     }
 ) ->
     Context = create(BackendCfg),
-    load(Context),
+    ok = load(Context),
     State#{
         enable := true,
         context := Context,
@@ -376,7 +385,7 @@ disable_retainer(
         context := Context
     } = State
 ) ->
-    unload(),
+    ok = unload(),
     ok = close(Context),
     State#{
         enable := false,

apps/emqx_retainer/src/emqx_retainer_dispatcher.erl

@@ -44,6 +44,9 @@
 ]).
 
 -type limiter() :: emqx_htb_limiter:limiter().
+-type context() :: emqx_retainer:context().
+-type topic() :: emqx_types:topic().
+-type cursor() :: emqx_retainer:cursor().
 
 -define(POOL, ?MODULE).
 

apps/emqx_retainer/src/emqx_retainer_mnesia.erl

@@ -27,6 +27,7 @@
 %% emqx_retainer callbacks
 -export([
     create/1,
+    update/2,
     close/1,
     delete_message/2,
     store_retained/2,
@@ -102,7 +103,7 @@ create(#{storage_type := StorageType}) ->
         StorageType
     ),
     %% The context is not used by this backend
-    #{}.
+    #{storage_type => StorageType}.
 
 create_table(Table, RecordName, Attributes, Type, StorageType) ->
     Copies =
@@ -138,6 +139,11 @@ create_table(Table, RecordName, Attributes, Type, StorageType) ->
             ok
     end.
 
+update(#{storage_type := StorageType}, #{storage_type := StorageType}) ->
+    ok;
+update(_Context, _NewConfig) ->
+    need_recreate.
+
 close(_Context) -> ok.
 
 store_retained(_Context, Msg = #message{topic = Topic}) ->

apps/emqx_retainer/test/emqx_retainer_SUITE.erl

@@ -19,8 +19,6 @@
 -compile(export_all).
 -compile(nowarn_export_all).
 
--define(CLUSTER_RPC_SHARD, emqx_cluster_rpc_shard).
-
 -include("emqx_retainer.hrl").
 
 -include_lib("eunit/include/eunit.hrl").
@@ -789,6 +787,11 @@ t_compatibility_for_deliver_rate(_) ->
         Parser(DeliveryInf)
     ).
 
+t_update_config(_) ->
+    OldConf = emqx_config:get([retainer]),
+    NewConf = emqx_utils_maps:deep_put([backend, storage_type], OldConf, disk),
+    emqx_retainer:update_config(NewConf).
+
 %%--------------------------------------------------------------------
 %% Helper functions
 %%--------------------------------------------------------------------

apps/emqx_telemetry/test/emqx_telemetry_SUITE.erl

@@ -621,7 +621,7 @@ mock_httpc() ->
     ).
 
 mock_advanced_mqtt_features() ->
-    Context = undefined,
+    Context = emqx_retainer:context(),
     lists:foreach(
         fun(N) ->
             Num = integer_to_binary(N),