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%% This Source Code Form is subject to the terms of the Mozilla Public
%% License, v. 2.0. If a copy of the MPL was not distributed with this
%% file, You can obtain one at https://mozilla.org/MPL/2.0/.
%%
%% Copyright (c) 2007-2020 VMware, Inc. or its affiliates. All rights reserved.
%%
%% @private
-module(amqp_channels_manager).
-include("amqp_client_internal.hrl").
-behaviour(gen_server).
-export([start_link/3, open_channel/4, set_channel_max/2, is_empty/1,
num_channels/1, pass_frame/3, signal_connection_closing/3,
process_channel_frame/4]).
-export([init/1, terminate/2, code_change/3, handle_call/3, handle_cast/2,
handle_info/2]).
-record(state, {connection,
channel_sup_sup,
map_num_pa = gb_trees:empty(), %% Number -> {Pid, AState}
map_pid_num = #{}, %% Pid -> Number
channel_max = ?MAX_CHANNEL_NUMBER,
closing = false}).
%%---------------------------------------------------------------------------
%% Interface
%%---------------------------------------------------------------------------
start_link(Connection, ConnName, ChSupSup) ->
gen_server:start_link(?MODULE, [Connection, ConnName, ChSupSup], []).
open_channel(ChMgr, ProposedNumber, Consumer, InfraArgs) ->
gen_server:call(ChMgr, {open_channel, ProposedNumber, Consumer, InfraArgs},
amqp_util:call_timeout()).
set_channel_max(ChMgr, ChannelMax) ->
gen_server:cast(ChMgr, {set_channel_max, ChannelMax}).
is_empty(ChMgr) ->
gen_server:call(ChMgr, is_empty, amqp_util:call_timeout()).
num_channels(ChMgr) ->
gen_server:call(ChMgr, num_channels, amqp_util:call_timeout()).
pass_frame(ChMgr, ChNumber, Frame) ->
gen_server:cast(ChMgr, {pass_frame, ChNumber, Frame}).
signal_connection_closing(ChMgr, ChannelCloseType, Reason) ->
gen_server:cast(ChMgr, {connection_closing, ChannelCloseType, Reason}).
process_channel_frame(Frame, Channel, ChPid, AState) ->
case rabbit_command_assembler:process(Frame, AState) of
{ok, NewAState} -> NewAState;
{ok, Method, NewAState} -> rabbit_channel_common:do(ChPid, Method),
NewAState;
{ok, Method, Content, NewAState} -> rabbit_channel_common:do(ChPid, Method,
Content),
NewAState;
{error, Reason} -> ChPid ! {channel_exit, Channel,
Reason},
AState
end.
%%---------------------------------------------------------------------------
%% gen_server callbacks
%%---------------------------------------------------------------------------
init([Connection, ConnName, ChSupSup]) ->
?store_proc_name(ConnName),
{ok, #state{connection = Connection, channel_sup_sup = ChSupSup}}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
handle_call({open_channel, ProposedNumber, Consumer, InfraArgs}, _,
State = #state{closing = false}) ->
handle_open_channel(ProposedNumber, Consumer, InfraArgs, State);
handle_call(is_empty, _, State) ->
{reply, internal_is_empty(State), State};
handle_call(num_channels, _, State) ->
{reply, internal_num_channels(State), State}.
handle_cast({set_channel_max, ChannelMax}, State) ->
{noreply, State#state{channel_max = ChannelMax}};
handle_cast({pass_frame, ChNumber, Frame}, State) ->
{noreply, internal_pass_frame(ChNumber, Frame, State)};
handle_cast({connection_closing, ChannelCloseType, Reason}, State) ->
handle_connection_closing(ChannelCloseType, Reason, State).
handle_info({'DOWN', _, process, Pid, Reason}, State) ->
handle_down(Pid, Reason, State).
%%---------------------------------------------------------------------------
%% Internal plumbing
%%---------------------------------------------------------------------------
handle_open_channel(ProposedNumber, Consumer, InfraArgs,
State = #state{channel_sup_sup = ChSupSup}) ->
case new_number(ProposedNumber, State) of
{ok, Number} ->
{ok, _ChSup, {Ch, AState}} =
amqp_channel_sup_sup:start_channel_sup(ChSupSup, InfraArgs,
Number, Consumer),
NewState = internal_register(Number, Ch, AState, State),
erlang:monitor(process, Ch),
{reply, {ok, Ch}, NewState};
{error, _} = Error ->
{reply, Error, State}
end.
new_number(none, #state{channel_max = ChannelMax, map_num_pa = MapNPA}) ->
case gb_trees:is_empty(MapNPA) of
true -> {ok, 1};
false -> {Smallest, _} = gb_trees:smallest(MapNPA),
if Smallest > 1 ->
{ok, Smallest - 1};
true ->
{Largest, _} = gb_trees:largest(MapNPA),
if Largest < ChannelMax -> {ok, Largest + 1};
true -> find_free(MapNPA)
end
end
end;
new_number(Proposed, State = #state{channel_max = ChannelMax,
map_num_pa = MapNPA}) ->
IsValid = Proposed > 0 andalso Proposed =< ChannelMax andalso
not gb_trees:is_defined(Proposed, MapNPA),
case IsValid of true -> {ok, Proposed};
false -> new_number(none, State)
end.
find_free(MapNPA) ->
find_free(gb_trees:iterator(MapNPA), 1).
find_free(It, Candidate) ->
case gb_trees:next(It) of
{Number, _, It1} -> if Number > Candidate ->
{ok, Number - 1};
Number =:= Candidate ->
find_free(It1, Candidate + 1)
end;
none -> {error, out_of_channel_numbers}
end.
handle_down(Pid, Reason, State) ->
case internal_lookup_pn(Pid, State) of
undefined -> {stop, {error, unexpected_down}, State};
Number -> handle_channel_down(Pid, Number, Reason, State)
end.
handle_channel_down(Pid, Number, Reason, State) ->
maybe_report_down(Pid, case Reason of {shutdown, R} -> R;
_ -> Reason
end,
State),
NewState = internal_unregister(Number, Pid, State),
check_all_channels_terminated(NewState),
{noreply, NewState}.
maybe_report_down(_Pid, normal, _State) ->
ok;
maybe_report_down(_Pid, shutdown, _State) ->
ok;
maybe_report_down(_Pid, {app_initiated_close, _, _}, _State) ->
ok;
maybe_report_down(_Pid, {server_initiated_close, _, _}, _State) ->
ok;
maybe_report_down(_Pid, {connection_closing, _}, _State) ->
ok;
maybe_report_down(_Pid, {server_misbehaved, AmqpError},
#state{connection = Connection}) ->
amqp_gen_connection:server_misbehaved(Connection, AmqpError);
maybe_report_down(Pid, Other, #state{connection = Connection}) ->
amqp_gen_connection:channel_internal_error(Connection, Pid, Other).
check_all_channels_terminated(#state{closing = false}) ->
ok;
check_all_channels_terminated(State = #state{closing = true,
connection = Connection}) ->
case internal_is_empty(State) of
true -> amqp_gen_connection:channels_terminated(Connection);
false -> ok
end.
handle_connection_closing(ChannelCloseType, Reason,
State = #state{connection = Connection}) ->
case internal_is_empty(State) of
true -> amqp_gen_connection:channels_terminated(Connection);
false -> signal_channels_connection_closing(ChannelCloseType, Reason,
State)
end,
{noreply, State#state{closing = true}}.
%%---------------------------------------------------------------------------
internal_pass_frame(Number, Frame, State) ->
case internal_lookup_npa(Number, State) of
undefined ->
?LOG_INFO("Dropping frame ~p for invalid or closed "
"channel number ~p~n", [Frame, Number]),
State;
{ChPid, AState} ->
NewAState = process_channel_frame(Frame, Number, ChPid, AState),
internal_update_npa(Number, ChPid, NewAState, State)
end.
internal_register(Number, Pid, AState,
State = #state{map_num_pa = MapNPA, map_pid_num = MapPN}) ->
MapNPA1 = gb_trees:enter(Number, {Pid, AState}, MapNPA),
MapPN1 = maps:put(Pid, Number, MapPN),
State#state{map_num_pa = MapNPA1,
map_pid_num = MapPN1}.
internal_unregister(Number, Pid,
State = #state{map_num_pa = MapNPA, map_pid_num = MapPN}) ->
MapNPA1 = gb_trees:delete(Number, MapNPA),
MapPN1 = maps:remove(Pid, MapPN),
State#state{map_num_pa = MapNPA1,
map_pid_num = MapPN1}.
internal_is_empty(#state{map_num_pa = MapNPA}) ->
gb_trees:is_empty(MapNPA).
internal_num_channels(#state{map_num_pa = MapNPA}) ->
gb_trees:size(MapNPA).
internal_lookup_npa(Number, #state{map_num_pa = MapNPA}) ->
case gb_trees:lookup(Number, MapNPA) of {value, PA} -> PA;
none -> undefined
end.
internal_lookup_pn(Pid, #state{map_pid_num = MapPN}) ->
case maps:find(Pid, MapPN) of {ok, Number} -> Number;
error -> undefined
end.
internal_update_npa(Number, Pid, AState, State = #state{map_num_pa = MapNPA}) ->
State#state{map_num_pa = gb_trees:update(Number, {Pid, AState}, MapNPA)}.
signal_channels_connection_closing(ChannelCloseType, Reason,
#state{map_pid_num = MapPN}) ->
[amqp_channel:connection_closing(Pid, ChannelCloseType, Reason)
|| Pid <- maps:keys(MapPN)].
|
