refactor: move session stuff from `emqx_ds` to `emqx_persistent_session_ds`

Part of https://emqx.atlassian.net/browse/EMQX-10942

apps/emqx/integration_test/emqx_ds_SUITE.erl

@@ -246,7 +246,7 @@ t_session_subscription_idempotency(Config) ->
             ?assertMatch({ok, [_]}, get_all_iterator_ids(Node1)),
             ?assertMatch(
                 {ok, #{}, #{SubTopicFilterWords := #{}}},
-                erpc:call(Node1, emqx_ds, session_open, [ClientId])
+                erpc:call(Node1, emqx_persistent_session_ds, session_open, [ClientId])
             )
         end
     ),

apps/emqx/src/emqx_persistent_message.erl

@@ -57,6 +57,7 @@ init() ->
             }
         ),
         ok = emqx_persistent_session_ds_router:init_tables(),
+        ok = emqx_persistent_session_ds:create_tables(),
         ok
     end).
 

apps/emqx/src/emqx_persistent_session_ds.erl

@@ -55,6 +55,13 @@
     terminate/2
 ]).
 
+%% session table operations
+-export([create_tables/0]).
+
+-ifdef(TEST).
+-export([session_open/1]).
+-endif.
+
 %% RPC
 -export([
     ensure_iterator_closed_on_all_shards/1,
@@ -71,8 +78,13 @@
 -define(DEFAULT_KEYSPACE, default).
 -define(DS_SHARD, {?DEFAULT_KEYSPACE, ?DS_SHARD_ID}).
 
--type id() :: emqx_ds:session_id().
+%% Currently, this is the clientid.  We avoid `emqx_types:clientid()' because that can be
+%% an atom, in theory (?).
+-type id() :: binary().
 -type iterator() :: emqx_ds:iterator().
+-type iterator_id() :: emqx_ds:iterator_id().
+-type topic_filter() :: emqx_ds:topic_filter().
+-type iterators() :: #{topic_filter() => iterator()}.
 -type session() :: #{
     %% Client ID
     id := id(),
@@ -92,6 +104,8 @@
 -type conninfo() :: emqx_session:conninfo().
 -type replies() :: emqx_session:replies().
 
+-export_type([id/0]).
+
 %%
 
 -spec create(clientinfo(), conninfo(), emqx_session:conf()) ->
@@ -118,11 +132,11 @@ open(#{clientid := ClientID}, _ConnInfo) ->
     end.
 
 ensure_session(ClientID, Conf) ->
-    {ok, Session, #{}} = emqx_ds:session_ensure_new(ClientID, Conf),
+    {ok, Session, #{}} = session_ensure_new(ClientID, Conf),
     Session#{iterators => #{}}.
 
 open_session(ClientID) ->
-    case emqx_ds:session_open(ClientID) of
+    case session_open(ClientID) of
         {ok, Session, Iterators} ->
             Session#{iterators => prep_iterators(Iterators)};
         false ->
@@ -144,7 +158,7 @@ destroy(#{clientid := ClientID}) ->
 
 destroy_session(ClientID) ->
     _ = ensure_all_iterators_closed(ClientID),
-    emqx_ds:session_drop(ClientID).
+    session_drop(ClientID).
 
 %%--------------------------------------------------------------------
 %% Info, Stats
@@ -352,7 +366,7 @@ add_subscription(TopicFilterBin, SubOpts, DSSessionID) ->
     % and iterator information can be reconstructed from this table, if needed.
     ok = emqx_persistent_session_ds_router:do_add_route(TopicFilterBin, DSSessionID),
     TopicFilter = emqx_topic:words(TopicFilterBin),
-    {ok, Iterator, IsNew} = emqx_ds:session_add_iterator(
+    {ok, Iterator, IsNew} = session_add_iterator(
         DSSessionID, TopicFilter, SubOpts
     ),
     Ctx = #{iterator => Iterator, is_new => IsNew},
@@ -368,7 +382,7 @@ add_subscription(TopicFilterBin, SubOpts, DSSessionID) ->
     iterator().
 update_subscription(TopicFilterBin, Iterator, SubOpts, DSSessionID) ->
     TopicFilter = emqx_topic:words(TopicFilterBin),
-    {ok, NIterator, false} = emqx_ds:session_add_iterator(
+    {ok, NIterator, false} = session_add_iterator(
         DSSessionID, TopicFilter, SubOpts
     ),
     ok = ?tp(persistent_session_ds_iterator_updated, #{iterator => Iterator}),
@@ -415,7 +429,7 @@ del_subscription(TopicFilterBin, #{id := IteratorID}, DSSessionID) ->
     ?tp_span(
         persistent_session_ds_iterator_delete,
         Ctx,
-        emqx_ds:session_del_iterator(DSSessionID, TopicFilter)
+        session_del_iterator(DSSessionID, TopicFilter)
     ),
     ok = emqx_persistent_session_ds_router:do_delete_route(TopicFilterBin, DSSessionID).
 
@@ -448,3 +462,210 @@ ensure_all_iterators_closed(DSSessionID) ->
 do_ensure_all_iterators_closed(DSSessionID) ->
     ok = emqx_ds_storage_layer:discard_iterator_prefix(?DS_SHARD, DSSessionID),
     ok.
+
+%%--------------------------------------------------------------------
+%% Session tables operations
+%%--------------------------------------------------------------------
+
+-define(SESSION_TAB, emqx_ds_session).
+-define(ITERATOR_REF_TAB, emqx_ds_iterator_ref).
+-define(DS_MRIA_SHARD, emqx_ds_shard).
+
+-record(session, {
+    %% same as clientid
+    id :: id(),
+    %% creation time
+    created_at :: _Millisecond :: non_neg_integer(),
+    expires_at = never :: _Millisecond :: non_neg_integer() | never,
+    %% for future usage
+    props = #{} :: map()
+}).
+
+-record(iterator_ref, {
+    ref_id :: {id(), emqx_ds:topic_filter()},
+    it_id :: emqx_ds:iterator_id(),
+    start_time :: emqx_ds:time(),
+    props = #{} :: map()
+}).
+
+create_tables() ->
+    ok = mria:create_table(
+        ?SESSION_TAB,
+        [
+            {rlog_shard, ?DS_MRIA_SHARD},
+            {type, set},
+            {storage, storage()},
+            {record_name, session},
+            {attributes, record_info(fields, session)}
+        ]
+    ),
+    ok = mria:create_table(
+        ?ITERATOR_REF_TAB,
+        [
+            {rlog_shard, ?DS_MRIA_SHARD},
+            {type, ordered_set},
+            {storage, storage()},
+            {record_name, iterator_ref},
+            {attributes, record_info(fields, iterator_ref)}
+        ]
+    ),
+    ok.
+
+-dialyzer({nowarn_function, storage/0}).
+storage() ->
+    %% FIXME: This is a temporary workaround to avoid crashes when starting on Windows
+    case mria:rocksdb_backend_available() of
+        true ->
+            rocksdb_copies;
+        _ ->
+            disc_copies
+    end.
+
+%% @doc Called when a client connects. This function looks up a
+%% session or returns `false` if previous one couldn't be found.
+%%
+%% This function also spawns replay agents for each iterator.
+%%
+%% Note: session API doesn't handle session takeovers, it's the job of
+%% the broker.
+-spec session_open(id()) ->
+    {ok, session(), iterators()} | false.
+session_open(SessionId) ->
+    transaction(fun() ->
+        case mnesia:read(?SESSION_TAB, SessionId, write) of
+            [Record = #session{}] ->
+                Session = export_record(Record),
+                IteratorRefs = session_read_iterators(SessionId),
+                Iterators = export_iterators(IteratorRefs),
+                {ok, Session, Iterators};
+            [] ->
+                false
+        end
+    end).
+
+-spec session_ensure_new(id(), _Props :: map()) ->
+    {ok, session(), iterators()}.
+session_ensure_new(SessionId, Props) ->
+    transaction(fun() ->
+        ok = session_drop_iterators(SessionId),
+        Session = export_record(session_create(SessionId, Props)),
+        {ok, Session, #{}}
+    end).
+
+session_create(SessionId, Props) ->
+    Session = #session{
+        id = SessionId,
+        created_at = erlang:system_time(millisecond),
+        expires_at = never,
+        props = Props
+    },
+    ok = mnesia:write(?SESSION_TAB, Session, write),
+    Session.
+
+%% @doc Called when a client reconnects with `clean session=true' or
+%% during session GC
+-spec session_drop(id()) -> ok.
+session_drop(DSSessionId) ->
+    transaction(fun() ->
+        %% TODO: ensure all iterators from this clientid are closed?
+        ok = session_drop_iterators(DSSessionId),
+        ok = mnesia:delete(?SESSION_TAB, DSSessionId, write)
+    end).
+
+session_drop_iterators(DSSessionId) ->
+    IteratorRefs = session_read_iterators(DSSessionId),
+    ok = lists:foreach(fun session_del_iterator/1, IteratorRefs).
+
+%% @doc Called when a client subscribes to a topic. Idempotent.
+-spec session_add_iterator(id(), topic_filter(), _Props :: map()) ->
+    {ok, iterator(), _IsNew :: boolean()}.
+session_add_iterator(DSSessionId, TopicFilter, Props) ->
+    IteratorRefId = {DSSessionId, TopicFilter},
+    transaction(fun() ->
+        case mnesia:read(?ITERATOR_REF_TAB, IteratorRefId, write) of
+            [] ->
+                IteratorRef = session_insert_iterator(DSSessionId, TopicFilter, Props),
+                Iterator = export_record(IteratorRef),
+                ?tp(
+                    ds_session_subscription_added,
+                    #{iterator => Iterator, session_id => DSSessionId}
+                ),
+                {ok, Iterator, _IsNew = true};
+            [#iterator_ref{} = IteratorRef] ->
+                NIteratorRef = session_update_iterator(IteratorRef, Props),
+                NIterator = export_record(NIteratorRef),
+                ?tp(
+                    ds_session_subscription_present,
+                    #{iterator => NIterator, session_id => DSSessionId}
+                ),
+                {ok, NIterator, _IsNew = false}
+        end
+    end).
+
+session_insert_iterator(DSSessionId, TopicFilter, Props) ->
+    {IteratorId, StartMS} = new_iterator_id(DSSessionId),
+    IteratorRef = #iterator_ref{
+        ref_id = {DSSessionId, TopicFilter},
+        it_id = IteratorId,
+        start_time = StartMS,
+        props = Props
+    },
+    ok = mnesia:write(?ITERATOR_REF_TAB, IteratorRef, write),
+    IteratorRef.
+
+session_update_iterator(IteratorRef, Props) ->
+    NIteratorRef = IteratorRef#iterator_ref{props = Props},
+    ok = mnesia:write(?ITERATOR_REF_TAB, NIteratorRef, write),
+    NIteratorRef.
+
+%% @doc Called when a client unsubscribes from a topic.
+-spec session_del_iterator(id(), topic_filter()) -> ok.
+session_del_iterator(DSSessionId, TopicFilter) ->
+    IteratorRefId = {DSSessionId, TopicFilter},
+    transaction(fun() ->
+        mnesia:delete(?ITERATOR_REF_TAB, IteratorRefId, write)
+    end).
+
+session_del_iterator(#iterator_ref{ref_id = IteratorRefId}) ->
+    mnesia:delete(?ITERATOR_REF_TAB, IteratorRefId, write).
+
+session_read_iterators(DSSessionId) ->
+    % NOTE: somewhat convoluted way to trick dialyzer
+    Pat = erlang:make_tuple(record_info(size, iterator_ref), '_', [
+        {1, iterator_ref},
+        {#iterator_ref.ref_id, {DSSessionId, '_'}}
+    ]),
+    mnesia:match_object(?ITERATOR_REF_TAB, Pat, read).
+
+-spec new_iterator_id(id()) -> {iterator_id(), emqx_ds:time()}.
+new_iterator_id(DSSessionId) ->
+    NowMS = erlang:system_time(microsecond),
+    IteratorId = <<DSSessionId/binary, (emqx_guid:gen())/binary>>,
+    {IteratorId, NowMS}.
+
+%%--------------------------------------------------------------------------------
+
+transaction(Fun) ->
+    {atomic, Res} = mria:transaction(?DS_MRIA_SHARD, Fun),
+    Res.
+
+%%--------------------------------------------------------------------------------
+
+export_iterators(IteratorRefs) ->
+    lists:foldl(
+        fun(IteratorRef = #iterator_ref{ref_id = {_DSSessionId, TopicFilter}}, Acc) ->
+            Acc#{TopicFilter => export_record(IteratorRef)}
+        end,
+        #{},
+        IteratorRefs
+    ).
+
+export_record(#session{} = Record) ->
+    export_record(Record, #session.id, [id, created_at, expires_at, props], #{});
+export_record(#iterator_ref{} = Record) ->
+    export_record(Record, #iterator_ref.it_id, [id, start_time, props], #{}).
+
+export_record(Record, I, [Field | Rest], Acc) ->
+    export_record(Record, I + 1, Rest, Acc#{Field => element(I, Record)});
+export_record(_, _, [], Acc) ->
+    Acc.

apps/emqx/src/emqx_persistent_session_ds/emqx_ps_ds_int.hrl

@@ -21,7 +21,7 @@
 
 -record(ps_route, {
     topic :: binary(),
-    dest :: emqx_ds:session_id()
+    dest :: emqx_persistent_session_ds:id()
 }).
 -record(ps_routeidx, {
     entry :: emqx_topic_index:key(emqx_persistent_session_ds_router:dest()),

apps/emqx/src/emqx_persistent_session_ds_router.erl

@@ -40,7 +40,7 @@
 -export([has_route/2]).
 -endif.
 
--type dest() :: emqx_ds:session_id().
+-type dest() :: emqx_persistent_session_ds:id().
 
 -export_type([dest/0]).
 
@@ -159,7 +159,7 @@ print_routes(Topic) ->
         match_routes(Topic)
     ).
 
--spec cleanup_routes(emqx_ds:session_id()) -> ok.
+-spec cleanup_routes(emqx_persistent_session_ds:id()) -> ok.
 cleanup_routes(DSSessionId) ->
     %% NOTE
     %% No point in transaction here because all the operations on filters table are dirty.

apps/emqx/src/proto/emqx_persistent_session_ds_proto_v1.erl

@@ -66,7 +66,7 @@ close_iterator(Nodes, IteratorID) ->
 
 -spec close_all_iterators(
     [node()],
-    emqx_ds:session_id()
+    emqx_persistent_session_ds:id()
 ) ->
     emqx_rpc:erpc_multicall(ok).
 close_all_iterators(Nodes, DSSessionID) ->

apps/emqx_durable_storage/src/emqx_ds.erl

@@ -24,17 +24,6 @@
 -export([message_store/2, message_store/1, message_stats/0]).
 %%   Iterator:
 -export([iterator_update/2, iterator_next/1, iterator_stats/0]).
-%%   Session:
--export([
-    session_open/1,
-    session_ensure_new/2,
-    session_drop/1,
-    session_suspend/1,
-    session_add_iterator/3,
-    session_get_iterator_id/2,
-    session_del_iterator/2,
-    session_stats/0
-]).
 
 %% internal exports:
 -export([]).
@@ -44,7 +33,6 @@
     message_id/0,
     message_stats/0,
     message_store_opts/0,
-    session_id/0,
     replay/0,
     replay_id/0,
     iterator_id/0,
@@ -56,27 +44,10 @@
     time/0
 ]).
 
--include("emqx_ds_int.hrl").
-
 %%================================================================================
 %% Type declarations
 %%================================================================================
 
-%% Session
-%% See also: `#session{}`.
--type session() :: #{
-    id := emqx_ds:session_id(),
-    created_at := _Millisecond :: non_neg_integer(),
-    expires_at := _Millisecond :: non_neg_integer() | never,
-    props := map()
-}.
-
--type iterators() :: #{topic_filter() => iterator()}.
-
-%% Currently, this is the clientid.  We avoid `emqx_types:clientid()' because that can be
-%% an atom, in theory (?).
--type session_id() :: binary().
-
 -type iterator() :: term().
 
 -type iterator_id() :: binary().
@@ -148,144 +119,6 @@ message_stats() ->
 %% Session
 %%--------------------------------------------------------------------------------
 
-%% @doc Called when a client connects. This function looks up a
-%% session or returns `false` if previous one couldn't be found.
-%%
-%% This function also spawns replay agents for each iterator.
-%%
-%% Note: session API doesn't handle session takeovers, it's the job of
-%% the broker.
--spec session_open(session_id()) ->
-    {ok, session(), iterators()} | false.
-session_open(SessionId) ->
-    transaction(fun() ->
-        case mnesia:read(?SESSION_TAB, SessionId, write) of
-            [Record = #session{}] ->
-                Session = export_record(Record),
-                IteratorRefs = session_read_iterators(SessionId),
-                Iterators = export_iterators(IteratorRefs),
-                {ok, Session, Iterators};
-            [] ->
-                false
-        end
-    end).
-
--spec session_ensure_new(session_id(), _Props :: map()) ->
-    {ok, session(), iterators()}.
-session_ensure_new(SessionId, Props) ->
-    transaction(fun() ->
-        ok = session_drop_iterators(SessionId),
-        Session = export_record(session_create(SessionId, Props)),
-        {ok, Session, #{}}
-    end).
-
-session_create(SessionId, Props) ->
-    Session = #session{
-        id = SessionId,
-        created_at = erlang:system_time(millisecond),
-        expires_at = never,
-        props = Props
-    },
-    ok = mnesia:write(?SESSION_TAB, Session, write),
-    Session.
-
-%% @doc Called when a client reconnects with `clean session=true' or
-%% during session GC
--spec session_drop(session_id()) -> ok.
-session_drop(DSSessionId) ->
-    transaction(fun() ->
-        %% TODO: ensure all iterators from this clientid are closed?
-        ok = session_drop_iterators(DSSessionId),
-        ok = mnesia:delete(?SESSION_TAB, DSSessionId, write)
-    end).
-
-session_drop_iterators(DSSessionId) ->
-    IteratorRefs = session_read_iterators(DSSessionId),
-    ok = lists:foreach(fun session_del_iterator/1, IteratorRefs).
-
-%% @doc Called when a client disconnects. This function terminates all
-%% active processes related to the session.
--spec session_suspend(session_id()) -> ok | {error, session_not_found}.
-session_suspend(_SessionId) ->
-    %% TODO
-    ok.
-
-%% @doc Called when a client subscribes to a topic. Idempotent.
--spec session_add_iterator(session_id(), topic_filter(), _Props :: map()) ->
-    {ok, iterator(), _IsNew :: boolean()}.
-session_add_iterator(DSSessionId, TopicFilter, Props) ->
-    IteratorRefId = {DSSessionId, TopicFilter},
-    transaction(fun() ->
-        case mnesia:read(?ITERATOR_REF_TAB, IteratorRefId, write) of
-            [] ->
-                IteratorRef = session_insert_iterator(DSSessionId, TopicFilter, Props),
-                Iterator = export_record(IteratorRef),
-                ?tp(
-                    ds_session_subscription_added,
-                    #{iterator => Iterator, session_id => DSSessionId}
-                ),
-                {ok, Iterator, _IsNew = true};
-            [#iterator_ref{} = IteratorRef] ->
-                NIteratorRef = session_update_iterator(IteratorRef, Props),
-                NIterator = export_record(NIteratorRef),
-                ?tp(
-                    ds_session_subscription_present,
-                    #{iterator => NIterator, session_id => DSSessionId}
-                ),
-                {ok, NIterator, _IsNew = false}
-        end
-    end).
-
-session_insert_iterator(DSSessionId, TopicFilter, Props) ->
-    {IteratorId, StartMS} = new_iterator_id(DSSessionId),
-    IteratorRef = #iterator_ref{
-        ref_id = {DSSessionId, TopicFilter},
-        it_id = IteratorId,
-        start_time = StartMS,
-        props = Props
-    },
-    ok = mnesia:write(?ITERATOR_REF_TAB, IteratorRef, write),
-    IteratorRef.
-
-session_update_iterator(IteratorRef, Props) ->
-    NIteratorRef = IteratorRef#iterator_ref{props = Props},
-    ok = mnesia:write(?ITERATOR_REF_TAB, NIteratorRef, write),
-    NIteratorRef.
-
--spec session_get_iterator_id(session_id(), topic_filter()) ->
-    {ok, iterator_id()} | {error, not_found}.
-session_get_iterator_id(DSSessionId, TopicFilter) ->
-    IteratorRefId = {DSSessionId, TopicFilter},
-    case mnesia:dirty_read(?ITERATOR_REF_TAB, IteratorRefId) of
-        [] ->
-            {error, not_found};
-        [#iterator_ref{it_id = IteratorId}] ->
-            {ok, IteratorId}
-    end.
-
-%% @doc Called when a client unsubscribes from a topic.
--spec session_del_iterator(session_id(), topic_filter()) -> ok.
-session_del_iterator(DSSessionId, TopicFilter) ->
-    IteratorRefId = {DSSessionId, TopicFilter},
-    transaction(fun() ->
-        mnesia:delete(?ITERATOR_REF_TAB, IteratorRefId, write)
-    end).
-
-session_del_iterator(#iterator_ref{ref_id = IteratorRefId}) ->
-    mnesia:delete(?ITERATOR_REF_TAB, IteratorRefId, write).
-
-session_read_iterators(DSSessionId) ->
-    % NOTE: somewhat convoluted way to trick dialyzer
-    Pat = erlang:make_tuple(record_info(size, iterator_ref), '_', [
-        {1, iterator_ref},
-        {#iterator_ref.ref_id, {DSSessionId, '_'}}
-    ]),
-    mnesia:match_object(?ITERATOR_REF_TAB, Pat, read).
-
--spec session_stats() -> #{}.
-session_stats() ->
-    #{}.
-
 %%--------------------------------------------------------------------------------
 %% Iterator (pull API)
 %%--------------------------------------------------------------------------------
@@ -309,36 +142,3 @@ iterator_stats() ->
 %%================================================================================
 %% Internal functions
 %%================================================================================
-
--spec new_iterator_id(session_id()) -> {iterator_id(), time()}.
-new_iterator_id(DSSessionId) ->
-    NowMS = erlang:system_time(microsecond),
-    IteratorId = <<DSSessionId/binary, (emqx_guid:gen())/binary>>,
-    {IteratorId, NowMS}.
-
-%%--------------------------------------------------------------------------------
-
-transaction(Fun) ->
-    {atomic, Res} = mria:transaction(?DS_MRIA_SHARD, Fun),
-    Res.
-
-%%--------------------------------------------------------------------------------
-
-export_iterators(IteratorRefs) ->
-    lists:foldl(
-        fun(IteratorRef = #iterator_ref{ref_id = {_DSSessionId, TopicFilter}}, Acc) ->
-            Acc#{TopicFilter => export_record(IteratorRef)}
-        end,
-        #{},
-        IteratorRefs
-    ).
-
-export_record(#session{} = Record) ->
-    export_record(Record, #session.id, [id, created_at, expires_at, props], #{});
-export_record(#iterator_ref{} = Record) ->
-    export_record(Record, #iterator_ref.it_id, [id, start_time, props], #{}).
-
-export_record(Record, I, [Field | Rest], Acc) ->
-    export_record(Record, I + 1, Rest, Acc#{Field => element(I, Record)});
-export_record(_, _, [], Acc) ->
-    Acc.

apps/emqx_durable_storage/src/emqx_ds_app.erl

@@ -4,44 +4,7 @@
 
 -module(emqx_ds_app).
 
--dialyzer({nowarn_function, storage/0}).
+-export([start/2]).
-
--export([start/2, storage/0]).
-
--include("emqx_ds_int.hrl").
 
 start(_Type, _Args) ->
-    init_mnesia(),
     emqx_ds_sup:start_link().
-
-init_mnesia() ->
-    ok = mria:create_table(
-        ?SESSION_TAB,
-        [
-            {rlog_shard, ?DS_MRIA_SHARD},
-            {type, set},
-            {storage, storage()},
-            {record_name, session},
-            {attributes, record_info(fields, session)}
-        ]
-    ),
-    ok = mria:create_table(
-        ?ITERATOR_REF_TAB,
-        [
-            {rlog_shard, ?DS_MRIA_SHARD},
-            {type, ordered_set},
-            {storage, storage()},
-            {record_name, iterator_ref},
-            {attributes, record_info(fields, iterator_ref)}
-        ]
-    ),
-    ok.
-
-storage() ->
-    %% FIXME: This is a temporary workaround to avoid crashes when starting on Windows
-    case mria:rocksdb_backend_available() of
-        true ->
-            rocksdb_copies;
-        _ ->
-            disc_copies
-    end.

apps/emqx_durable_storage/src/emqx_ds_int.hrl

@@ -1,40 +0,0 @@
-%%--------------------------------------------------------------------
-%% Copyright (c) 2022-2023 EMQ Technologies Co., Ltd. All Rights Reserved.
-%%
-%% Licensed under the Apache License, Version 2.0 (the "License");
-%% you may not use this file except in compliance with the License.
-%% You may obtain a copy of the License at
-%%
-%%     http://www.apache.org/licenses/LICENSE-2.0
-%%
-%% Unless required by applicable law or agreed to in writing, software
-%% distributed under the License is distributed on an "AS IS" BASIS,
-%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%% See the License for the specific language governing permissions and
-%% limitations under the License.
-%%--------------------------------------------------------------------
--ifndef(EMQX_DS_HRL).
--define(EMQX_DS_HRL, true).
-
--define(SESSION_TAB, emqx_ds_session).
--define(ITERATOR_REF_TAB, emqx_ds_iterator_ref).
--define(DS_MRIA_SHARD, emqx_ds_shard).
-
--record(session, {
-    %% same as clientid
-    id :: emqx_ds:session_id(),
-    %% creation time
-    created_at :: _Millisecond :: non_neg_integer(),
-    expires_at = never :: _Millisecond :: non_neg_integer() | never,
-    %% for future usage
-    props = #{} :: map()
-}).
-
--record(iterator_ref, {
-    ref_id :: {emqx_ds:session_id(), emqx_ds:topic_filter()},
-    it_id :: emqx_ds:iterator_id(),
-    start_time :: emqx_ds:time(),
-    props = #{} :: map()
-}).
-
--endif.