%% Copyright (c) 2011-2012, 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.
%% @doc Ranch API to start and stop listeners.
-module(ranch).
-export([start_listener/6]).
-export([stop_listener/1]).
-export([child_spec/6]).
-export([accept_ack/1]).
-export([get_port/1]).
-export([get_protocol_options/1]).
-export([set_protocol_options/2]).
-export([filter_options/3]).
-export([set_option_default/3]).
-export([require/1]).
%% @doc Start a listener for the given transport and protocol.
%%
%% A listener is effectively a pool of <em>NbAcceptors</em> acceptors.
%% Acceptors accept connections on the given <em>Transport</em> and forward
%% connections to the given <em>Protocol</em> handler. Both transport and
%% protocol modules can be given options through the <em>TransOpts</em> and
%% the <em>ProtoOpts</em> arguments. Available options are documented in the
%% <em>listen</em> transport function and in the protocol module of your choice.
%%
%% All acceptor and connection processes are supervised by the listener.
%%
%% It is recommended to set a large enough number of acceptors to improve
%% performance. The exact number depends of course on your hardware, on the
%% protocol used and on the number of expected simultaneous connections.
%%
%% The <em>Transport</em> option <em>max_connections</em> allows you to define
%% the maximum number of simultaneous connections for this listener. It defaults
%% to 1024. See <em>ranch_listener</em> for more details on limiting the number
%% of connections.
%%
%% <em>Ref</em> can be used to stop the listener later on.
%%
%% This function will return `{error, badarg}` if and only if the transport
%% module given doesn't appear to be correct.
-spec start_listener(any(), non_neg_integer(), module(), any(), module(), any())
-> {ok, pid()} | {error, badarg}.
start_listener(Ref, NbAcceptors, Transport, TransOpts, Protocol, ProtoOpts)
when is_integer(NbAcceptors) andalso is_atom(Transport)
andalso is_atom(Protocol) ->
case erlang:function_exported(Transport, name, 0) of
false ->
{error, badarg};
true ->
supervisor:start_child(ranch_sup, child_spec(Ref, NbAcceptors,
Transport, TransOpts, Protocol, ProtoOpts))
end.
%% @doc Stop a listener identified by <em>Ref</em>.
%%
%% Note that stopping the listener will close all currently running
%% connections abruptly.
-spec stop_listener(any()) -> ok | {error, not_found}.
stop_listener(Ref) ->
case supervisor:terminate_child(ranch_sup, {ranch_listener_sup, Ref}) of
ok ->
supervisor:delete_child(ranch_sup, {ranch_listener_sup, Ref});
{error, Reason} ->
{error, Reason}
end.
%% @doc Return a child spec suitable for embedding.
%%
%% When you want to embed Ranch in another application, you can use this
%% function to create a <em>ChildSpec</em> suitable for use in a supervisor.
%% The parameters are the same as in <em>start_listener/6</em> but rather
%% than hooking the listener to the Ranch internal supervisor, it just returns
%% the spec.
-spec child_spec(any(), non_neg_integer(), module(), any(), module(), any())
-> supervisor:child_spec().
child_spec(Ref, NbAcceptors, Transport, TransOpts, Protocol, ProtoOpts)
when is_integer(NbAcceptors) andalso is_atom(Transport)
andalso is_atom(Protocol) ->
{{ranch_listener_sup, Ref}, {ranch_listener_sup, start_link, [
Ref, NbAcceptors, Transport, TransOpts, Protocol, ProtoOpts
]}, permanent, 5000, supervisor, [ranch_listener_sup]}.
%% @doc Acknowledge the accepted connection.
%%
%% Effectively used to make sure the socket control has been given to
%% the protocol process before starting to use it.
-spec accept_ack(pid()) -> ok.
accept_ack(ListenerPid) ->
receive {shoot, ListenerPid} -> ok end.
%% @doc Return the listener's port.
-spec get_port(any()) -> inet:port_number().
get_port(Ref) ->
ListenerPid = ranch_server:lookup_listener(Ref),
{ok, Port} = ranch_listener:get_port(ListenerPid),
Port.
%% @doc Return the current protocol options for the given listener.
-spec get_protocol_options(any()) -> any().
get_protocol_options(Ref) ->
ListenerPid = ranch_server:lookup_listener(Ref),
{ok, ProtoOpts} = ranch_listener:get_protocol_options(ListenerPid),
ProtoOpts.
%% @doc Upgrade the protocol options for the given listener.
%%
%% The upgrade takes place at the acceptor level, meaning that only the
%% newly accepted connections receive the new protocol options. This has
%% no effect on the currently opened connections.
-spec set_protocol_options(any(), any()) -> ok.
set_protocol_options(Ref, ProtoOpts) ->
ListenerPid = ranch_server:lookup_listener(Ref),
ok = ranch_listener:set_protocol_options(ListenerPid, ProtoOpts).
%% @doc Filter a list of options and remove all unwanted values.
%%
%% It takes a list of options, a list of allowed keys and an accumulator.
%% This accumulator can be used to set default options that should never
%% be overriden.
-spec filter_options([{atom(), any()}], [atom()], Acc)
-> Acc when Acc :: [any()].
filter_options([], _, Acc) ->
Acc;
filter_options([Opt = {Key, _}|Tail], AllowedKeys, Acc) ->
case lists:member(Key, AllowedKeys) of
true -> filter_options(Tail, AllowedKeys, [Opt|Acc]);
false -> filter_options(Tail, AllowedKeys, Acc)
end.
%% @doc Add an option to a list, but only if it wasn't previously set.
-spec set_option_default(Opts, atom(), any())
-> Opts when Opts :: [{atom(), any()}].
set_option_default(Opts, Key, Value) ->
case lists:keymember(Key, 1, Opts) of
true -> Opts;
false -> [{Key, Value}|Opts]
end.
%% @doc Start the given applications if they were not already started.
-spec require(list(module())) -> ok.
require([]) ->
ok;
require([App|Tail]) ->
case application:start(App) of
ok -> ok;
{error, {already_started, App}} -> ok
end,
require(Tail).
