%% Copyright (c) 2011-2018, Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-module(ranch_acceptor).
-export([start_link/4]).
-export([loop/4]).
-spec start_link(inet:socket(), module(), module(), pid())
-> {ok, pid()}.
start_link(LSocket, Transport, Logger, ConnsSup) ->
Pid = spawn_link(?MODULE, loop, [LSocket, Transport, Logger, ConnsSup]),
{ok, Pid}.
-spec loop(inet:socket(), module(), module(), pid()) -> no_return().
loop(LSocket, Transport, Logger, ConnsSup) ->
_ = case Transport:accept(LSocket, infinity) of
{ok, CSocket} ->
case Transport:controlling_process(CSocket, ConnsSup) of
ok ->
%% This call will not return until process has been started
%% AND we are below the maximum number of connections.
ranch_conns_sup:start_protocol(ConnsSup, CSocket);
{error, _} ->
Transport:close(CSocket)
end;
%% Reduce the accept rate if we run out of file descriptors.
%% We can't accept anymore anyway, so we might as well wait
%% a little for the situation to resolve itself.
{error, emfile} ->
ranch:log(warning,
"Ranch acceptor reducing accept rate: out of file descriptors~n",
[], Logger),
receive after 100 -> ok end;
%% We want to crash if the listening socket got closed.
{error, Reason} when Reason =/= closed ->
ok
end,
flush(Logger),
?MODULE:loop(LSocket, Transport, Logger, ConnsSup).
flush(Logger) ->
receive Msg ->
ranch:log(warning,
"Ranch acceptor received unexpected message: ~p~n",
[Msg], Logger),
flush(Logger)
after 0 ->
ok
end.
