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refactor(sessds): Extract subscription mgmt logic to separate module

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ieQu1 2024-02-07 12:41:51 +01:00
parent 3000a8f286
commit 19c6d1127f
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GPG Key ID: 488654DF3FED6FDE
3 changed files with 167 additions and 87 deletions
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92
apps/emqx/src/emqx_persistent_session_ds.erl
View File

@ -209,7 +209,7 @@ info(created_at, #{s := S}) ->
info(is_persistent, #{}) ->
true;
info(subscriptions, #{s := S}) ->
subs_to_map(S);
emqx_persistent_session_ds_subs:to_map(S);
info(subscriptions_cnt, #{s := S}) ->
emqx_topic_gbt:size(emqx_persistent_session_ds_state:get_subscriptions(S));
info(subscriptions_max, #{props := Conf}) ->
@ -280,7 +280,7 @@ subscribe(
SubOpts,
Session = #{id := ID, s := S0}
) ->
case subs_lookup(TopicFilter, S0) of
case emqx_persistent_session_ds_subs:lookup(TopicFilter, S0) of
undefined ->
%% TODO: max subscriptions
@ -322,7 +322,7 @@ subscribe(
IsNew = false,
S1 = S0
end,
S = emqx_persistent_session_ds_state:put_subscription(TopicFilter, [], Subscription, S1),
S = emqx_persistent_session_ds_subs:on_subscribe(TopicFilter, Subscription, S1),
?tp(persistent_session_ds_subscription_added, #{
topic_filter => TopicFilter, sub => Subscription, is_new => IsNew
}),
@ -334,7 +334,7 @@ unsubscribe(
TopicFilter,
Session = #{id := ID, s := S0}
) ->
case subs_lookup(TopicFilter, S0) of
case emqx_persistent_session_ds_subs:lookup(TopicFilter, S0) of
undefined ->
{error, ?RC_NO_SUBSCRIPTION_EXISTED};
Subscription = #{props := SubOpts} ->
@ -344,13 +344,8 @@ unsubscribe(
-spec do_unsubscribe(id(), topic_filter(), subscription(), emqx_persistent_session_ds_state:t()) ->
emqx_persistent_session_ds_state:t().
do_unsubscribe(SessionId, TopicFilter, SubMeta0 = #{id := SubId}, S0) ->
%% Note: we cannot delete the subscription immediately, since its
%% metadata can be used during replay (see `process_batch'). We
%% instead mark it as deleted, and let `subscription_gc' function
%% dispatch it later:
SubMeta = SubMeta0#{deleted => true},
S1 = emqx_persistent_session_ds_state:put_subscription(TopicFilter, [], SubMeta, S0),
do_unsubscribe(SessionId, TopicFilter, Subscription = #{id := SubId}, S0) ->
S1 = emqx_persistent_session_ds_subs:on_unsubscribe(TopicFilter, Subscription, S0),
?tp(persistent_session_ds_subscription_delete, #{
session_id => SessionId, topic_filter => TopicFilter
}),
@ -365,7 +360,7 @@ do_unsubscribe(SessionId, TopicFilter, SubMeta0 = #{id := SubId}, S0) ->
-spec get_subscription(topic_filter(), session()) ->
emqx_types:subopts() | undefined.
get_subscription(TopicFilter, #{s := S}) ->
case subs_lookup(TopicFilter, S) of
case emqx_persistent_session_ds_subs:lookup(TopicFilter, S) of
_Subscription = #{props := SubOpts} ->
SubOpts;
undefined ->
@ -465,7 +460,7 @@ handle_timeout(
Session = emqx_session:ensure_timer(?TIMER_PULL, Timeout, Session1),
{ok, Publishes, Session};
handle_timeout(_ClientInfo, ?TIMER_GET_STREAMS, Session0 = #{s := S0}) ->
S1 = subscription_gc(S0),
S1 = emqx_persistent_session_ds_subs:gc(S0),
S = emqx_persistent_session_ds_stream_scheduler:renew_streams(S1),
Interval = emqx_config:get([session_persistence, renew_streams_interval]),
Session = emqx_session:ensure_timer(
@ -509,7 +504,6 @@ replay(ClientInfo, [], Session0 = #{s := S0}) ->
Session0,
Streams
),
logger:error("Replay streams: ~p~n~p", [Streams, Session]),
%% Note: we filled the buffer with the historical messages, and
%% from now on we'll rely on the normal inflight/flow control
%% mechanisms to replay them:
@ -687,7 +681,7 @@ session_drop(ID, Reason) ->
case emqx_persistent_session_ds_state:open(ID) of
{ok, S0} ->
?tp(debug, drop_persistent_session, #{client_id => ID, reason => Reason}),
_S = subs_fold(
_S = emqx_persistent_session_ds_subs:fold(
fun(TopicFilter, Subscription, S) ->
do_unsubscribe(ID, TopicFilter, Subscription, S)
end,
@ -905,74 +899,6 @@ do_drain_buffer(Inflight0, S0, Acc) ->
%%--------------------------------------------------------------------------------
%% @doc Remove subscriptions that have been marked for deletion, and
%% that don't have any unacked messages:
subscription_gc(S0) ->
subs_fold_all(
fun(TopicFilter, #{id := SubId, deleted := Deleted}, Acc) ->
case Deleted andalso has_no_unacked_streams(SubId, S0) of
true ->
emqx_persistent_session_ds_state:del_subscription(TopicFilter, [], Acc);
false ->
Acc
end
end,
S0,
S0
).
has_no_unacked_streams(SubId, S) ->
emqx_persistent_session_ds_state:fold_streams(
fun
({SID, _Stream}, Srs, Acc) when SID =:= SubId ->
emqx_persistent_session_ds_stream_scheduler:is_fully_acked(Srs, S) andalso Acc;
(_StreamKey, _Srs, Acc) ->
Acc
end,
true,
S
).
%% @doc It only returns subscriptions that haven't been marked for deletion:
subs_lookup(TopicFilter, S) ->
Subs = emqx_persistent_session_ds_state:get_subscriptions(S),
case emqx_topic_gbt:lookup(TopicFilter, [], Subs, undefined) of
#{deleted := true} ->
undefined;
Sub ->
Sub
end.
subs_to_map(S) ->
subs_fold(
fun(TopicFilter, #{props := Props}, Acc) -> Acc#{TopicFilter => Props} end,
#{},
S
).
subs_fold(Fun, AccIn, S) ->
subs_fold_all(
fun(TopicFilter, Sub = #{deleted := Deleted}, Acc) ->
case Deleted of
true -> Acc;
false -> Fun(TopicFilter, Sub, Acc)
end
end,
AccIn,
S
).
%% @doc Iterate over all subscriptions, including the deleted ones:
subs_fold_all(Fun, AccIn, S) ->
Subs = emqx_persistent_session_ds_state:get_subscriptions(S),
emqx_topic_gbt:fold(
fun(Key, Sub, Acc) -> Fun(emqx_topic_gbt:get_topic(Key), Sub, Acc) end,
AccIn,
Subs
).
%%--------------------------------------------------------------------------------
%% TODO: find a more reliable way to perform actions that have side
%% effects. Add `CBM:init' callback to the session behavior?
-spec ensure_timers(session()) -> session().

8
apps/emqx/src/emqx_persistent_session_ds_stream_scheduler.erl
View File

@ -126,10 +126,10 @@ find_new_streams(S) ->
renew_streams(S0) ->
S1 = remove_unsubscribed_streams(S0),
S2 = remove_fully_replayed_streams(S1),
emqx_topic_gbt:fold(
emqx_persistent_session_ds_subs:fold(
fun
(Key, _Subscription = #{start_time := StartTime, id := SubId, deleted := false}, Acc) ->
TopicFilter = emqx_topic:words(emqx_trie_search:get_topic(Key)),
(Key, #{start_time := StartTime, id := SubId, deleted := false}, Acc) ->
TopicFilter = emqx_topic:words(Key),
Streams = select_streams(
SubId,
emqx_ds:get_streams(?PERSISTENT_MESSAGE_DB, TopicFilter, StartTime),
@ -146,7 +146,7 @@ renew_streams(S0) ->
Acc
end,
S2,
emqx_persistent_session_ds_state:get_subscriptions(S2)
S2
).
-spec on_unsubscribe(

154
apps/emqx/src/emqx_persistent_session_ds_subs.erl Normal file
View File

@ -0,0 +1,154 @@
%%--------------------------------------------------------------------
%% Copyright (c) 2023-2024 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.
%%--------------------------------------------------------------------
%% @doc This module encapsulates the data related to the client's
%% subscriptions. It tries to reppresent the subscriptions as if they
%% were a simple key-value map.
%%
%% In reality, however, the session has to retain old the
%% subscriptions for longer to ensure the consistency of message
%% replay.
-module(emqx_persistent_session_ds_subs).
%% API:
-export([on_subscribe/3, on_unsubscribe/3, gc/1, lookup/2, to_map/1, fold/3, fold_all/3]).
-export_type([]).
%%================================================================================
%% Type declarations
%%================================================================================
%%================================================================================
%% API functions
%%================================================================================
%% @doc Process a new subscription
-spec on_subscribe(
emqx_persistent_session_ds:topic_filter(),
emqx_persistent_session_ds:subscription(),
emqx_persistent_session_ds_state:t()
) ->
emqx_persistent_session_ds_state:t().
on_subscribe(TopicFilter, Subscription, S) ->
emqx_persistent_session_ds_state:put_subscription(TopicFilter, [], Subscription, S).
%% @doc Process UNSUBSCRIBE
-spec on_unsubscribe(
emqx_persistent_session_ds:topic_filter(),
emqx_persistent_session_ds:subscription(),
emqx_persistent_session_ds_state:t()
) ->
emqx_persistent_session_ds_state:t().
on_unsubscribe(TopicFilter, Subscription0, S0) ->
%% Note: we cannot delete the subscription immediately, since its
%% metadata can be used during replay (see `process_batch'). We
%% instead mark it as deleted, and let `subscription_gc' function
%% dispatch it later:
Subscription = Subscription0#{deleted => true},
emqx_persistent_session_ds_state:put_subscription(TopicFilter, [], Subscription, S0).
%% @doc Remove subscriptions that have been marked for deletion, and
%% that don't have any unacked messages:
-spec gc(emqx_persistent_session_ds_state:t()) -> emqx_persistent_session_ds_state:t().
gc(S0) ->
fold_all(
fun(TopicFilter, #{id := SubId, deleted := Deleted}, Acc) ->
case Deleted andalso has_no_unacked_streams(SubId, S0) of
true ->
emqx_persistent_session_ds_state:del_subscription(TopicFilter, [], Acc);
false ->
Acc
end
end,
S0,
S0
).
%% @doc Fold over active subscriptions:
-spec lookup(emqx_persistent_session_ds:topic_filter(), emqx_persistent_session_ds_state:t()) ->
emqx_persistent_session_ds:subscription() | undefined.
lookup(TopicFilter, S) ->
Subs = emqx_persistent_session_ds_state:get_subscriptions(S),
case emqx_topic_gbt:lookup(TopicFilter, [], Subs, undefined) of
#{deleted := true} ->
undefined;
Sub ->
Sub
end.
%% @doc Convert active subscriptions to a map, for information
%% purpose:
-spec to_map(emqx_persistent_session_ds_state:t()) -> map().
to_map(S) ->
fold(
fun(TopicFilter, #{props := Props}, Acc) -> Acc#{TopicFilter => Props} end,
#{},
S
).
%% @doc Fold over active subscriptions:
-spec fold(
fun((emqx_types:topic(), emqx_persistent_session_ds:subscription(), Acc) -> Acc),
Acc,
emqx_persistent_session_ds_state:t()
) ->
Acc.
fold(Fun, AccIn, S) ->
fold_all(
fun(TopicFilter, Sub = #{deleted := Deleted}, Acc) ->
case Deleted of
true -> Acc;
false -> Fun(TopicFilter, Sub, Acc)
end
end,
AccIn,
S
).
%% @doc Fold over all subscriptions, including inactive ones:
-spec fold_all(
fun((emqx_types:topic(), emqx_persistent_session_ds:subscription(), Acc) -> Acc),
Acc,
emqx_persistent_session_ds_state:t()
) ->
Acc.
fold_all(Fun, AccIn, S) ->
Subs = emqx_persistent_session_ds_state:get_subscriptions(S),
emqx_topic_gbt:fold(
fun(Key, Sub, Acc) -> Fun(emqx_topic_gbt:get_topic(Key), Sub, Acc) end,
AccIn,
Subs
).
%%================================================================================
%% Internal functions
%%================================================================================
-spec has_no_unacked_streams(
emqx_persistent_session_ds:subscription_id(), emqx_persistent_session_ds_state:t()
) -> boolean().
has_no_unacked_streams(SubId, S) ->
emqx_persistent_session_ds_state:fold_streams(
fun
({SID, _Stream}, Srs, Acc) when SID =:= SubId ->
emqx_persistent_session_ds_stream_scheduler:is_fully_acked(Srs, S) andalso Acc;
(_StreamKey, _Srs, Acc) ->
Acc
end,
true,
S
).