Add timeout to cowboy_loop

LH: I have added a test that does both hibernate and timeout
    and fixed a related issue. I also tweaked the docs and tests.

test/handlers/loop_handler_timeout_hibernate_h.erl

@@ -0,0 +1,30 @@
+%% This module implements a loop handler that first
+%% sets a timeout, then hibernates, then ensures
+%% that the timeout initially set no longer triggers.
+%% If everything goes fine a 200 is returned. If the
+%% timeout triggers again a 299 is.
+
+-module(loop_handler_timeout_hibernate_h).
+
+-export([init/2]).
+-export([info/3]).
+-export([terminate/3]).
+
+init(Req, _) ->
+	self() ! message1,
+	{cowboy_loop, Req, undefined, 100}.
+
+info(message1, Req, State) ->
+	erlang:send_after(200, self(), message2),
+	{ok, Req, State, hibernate};
+info(message2, Req, State) ->
+	erlang:send_after(200, self(), message3),
+	%% Don't set a timeout now.
+	{ok, Req, State};
+info(message3, Req, State) ->
+	{stop, cowboy_req:reply(200, Req), State};
+info(timeout, Req, State) ->
+	{stop, cowboy_req:reply(<<"299 OK!">>, Req), State}.
+
+terminate(stop, _, _) ->
+	ok.

test/handlers/loop_handler_timeout_info_h.erl

@@ -0,0 +1,23 @@
+%% This module implements a loop handler that changes
+%% the timeout value to 500ms after the first message
+%% then sends itself another message after 1000ms.
+%% It is expected to timeout, that is, reply a 299.
+
+-module(loop_handler_timeout_info_h).
+
+-export([init/2]).
+-export([info/3]).
+-export([terminate/3]).
+
+init(Req, _) ->
+	self() ! message,
+	{cowboy_loop, Req, undefined}.
+
+info(message, Req, State) ->
+	erlang:send_after(200, self(), message),
+	{ok, Req, State, 100};
+info(timeout, Req, State) ->
+	{stop, cowboy_req:reply(<<"299 OK!">>, Req), State}.
+
+terminate(stop, _, _) ->
+	ok.

test/handlers/loop_handler_timeout_init_h.erl

@@ -0,0 +1,23 @@
+%% This module implements a loop handler that reads
+%% the request query for a timeout value, then sends
+%% itself a message after 1000ms. It replies a 200 when
+%% the message does not timeout and a 299 otherwise.
+
+-module(loop_handler_timeout_init_h).
+
+-export([init/2]).
+-export([info/3]).
+-export([terminate/3]).
+
+init(Req, _) ->
+	#{timeout := Timeout} = cowboy_req:match_qs([{timeout, int}], Req),
+	erlang:send_after(200, self(), message),
+	{cowboy_loop, Req, undefined, Timeout}.
+
+info(message, Req, State) ->
+	{stop, cowboy_req:reply(200, Req), State};
+info(timeout, Req, State) ->
+	{stop, cowboy_req:reply(<<"299 OK!">>, Req), State}.
+
+terminate(stop, _, _) ->
+	ok.

test/loop_handler_SUITE.erl

@@ -40,7 +40,10 @@ init_dispatch(_) ->
 	cowboy_router:compile([{'_', [
 		{"/long_polling", long_polling_h, []},
 		{"/loop_body", loop_handler_body_h, []},
-		{"/loop_timeout", loop_handler_timeout_h, []}
+		{"/loop_request_timeout", loop_handler_timeout_h, []},
+		{"/loop_timeout_init", loop_handler_timeout_init_h, []},
+		{"/loop_timeout_info", loop_handler_timeout_info_h, []},
+		{"/loop_timeout_hibernate", loop_handler_timeout_hibernate_h, []}
 	]}]).
 
 %% Tests.
@@ -79,6 +82,31 @@ long_polling_pipeline(Config) ->
 request_timeout(Config) ->
 	doc("Ensure that the request_timeout isn't applied when a request is ongoing."),
 	ConnPid = gun_open(Config),
-	Ref = gun:get(ConnPid, "/loop_timeout", [{<<"accept-encoding">>, <<"gzip">>}]),
+	Ref = gun:get(ConnPid, "/loop_request_timeout", [{<<"accept-encoding">>, <<"gzip">>}]),
 	{response, nofin, 200, _} = gun:await(ConnPid, Ref, 10000),
 	ok.
+
+timeout_hibernate(Config) ->
+	doc("Ensure that loop handler idle timeouts don't trigger after hibernate is returned."),
+	ConnPid = gun_open(Config),
+	Ref = gun:get(ConnPid, "/loop_timeout_hibernate", [{<<"accept-encoding">>, <<"gzip">>}]),
+	{response, fin, 200, _} = gun:await(ConnPid, Ref),
+	ok.
+
+timeout_info(Config) ->
+	doc("Ensure that loop handler idle timeouts trigger on time when set in info/3."),
+	ConnPid = gun_open(Config),
+	Ref = gun:get(ConnPid, "/loop_timeout_info", [{<<"accept-encoding">>, <<"gzip">>}]),
+	{response, fin, 299, _} = gun:await(ConnPid, Ref),
+	ok.
+
+timeout_init(Config) ->
+	doc("Ensure that loop handler idle timeouts trigger on time when set in init/2."),
+	ConnPid = gun_open(Config),
+	Ref = gun:get(ConnPid, "/loop_timeout_init?timeout=300",
+		[{<<"accept-encoding">>, <<"gzip">>}]),
+	{response, fin, 200, _} = gun:await(ConnPid, Ref),
+	Ref2 = gun:get(ConnPid, "/loop_timeout_init?timeout=100",
+		[{<<"accept-encoding">>, <<"gzip">>}]),
+	{response, fin, 299, _} = gun:await(ConnPid, Ref2),
+	ok.

test/sys_SUITE.erl

@@ -659,7 +659,7 @@ sys_get_state_loop(Config) ->
 	timer:sleep(100),
 	SupPid = get_remote_pid_tcp(Socket),
 	[{_, Pid, _, _}] = supervisor:which_children(SupPid),
-	{Req, Env, long_polling_sys_h, undefined} = sys:get_state(Pid),
+	{Req, Env, long_polling_sys_h, undefined, infinity} = sys:get_state(Pid),
 	#{pid := _, streamid := _} = Req,
 	#{dispatch := _} = Env,
 	ok.
@@ -784,7 +784,7 @@ sys_replace_state_loop(Config) ->
 	timer:sleep(100),
 	SupPid = get_remote_pid_tcp(Socket),
 	[{_, Pid, _, _}] = supervisor:which_children(SupPid),
-	{Req, Env, long_polling_sys_h, undefined} = sys:replace_state(Pid, fun(S) -> S end),
+	{Req, Env, long_polling_sys_h, undefined, infinity} = sys:replace_state(Pid, fun(S) -> S end),
 	#{pid := _, streamid := _} = Req,
 	#{dispatch := _} = Env,
 	ok.