New data delivery mechanism for HTTP/2+ Websocketdirect-data_delivery-for-h2-websocket

A new data_delivery mechanism called 'relay' has been added.
It bypasses stream handlers (and the buffering in cowboy_stream_h)
and sends the data directly to the process implementing
Websocket (and should work for other similar protocols
like HTTP/2 WebTransport).

Flow control in HTTP/2 is maintained in a simpler way,
via a configured flow value that is used to maintain
the window to a reasonable value when data is received.

The 'relay' data_delivery has been implemented for both
HTTP/2 and HTTP/3. It has not been implemented for HTTP/1.1
since switching protocol there overrides the connection process.

HTTP/2 Websocket is now better tested.

A bug was fixed with the 'stream_handlers' data_delivery
where active mode would not be reenabled if it was disabled
at some point.

The Websocket performance suite has been updated to
include tests that do not use Gun. Websocket modules
used by the performance suite use the 'relay' data_delivery
now. Performance is improved significantly with 'relay',
between 10% and 20% faster. HTTP/2 Websocket performance
is not on par with HTTP/1.1 still, but the remaining
difference is thought to be from the HTTP/2 overhead and
flow control.

1 files changed, 62 insertions, 20 deletions

diff --git a/test/ws_handler_SUITE.erl b/test/ws_handler_SUITE.erl
index ab9dbe2..00c584d 100644
--- a/test/ws_handler_SUITE.erl
+++ b/test/ws_handler_SUITE.erl
@@ -19,21 +19,40 @@
 -import(ct_helper, [config/2]).
 -import(ct_helper, [doc/1]).
 -import(cowboy_test, [gun_open/1]).
+-import(cowboy_test, [gun_open/2]).
 -import(cowboy_test, [gun_down/1]).
 
 %% ct.
 
 all() ->
-	[{group, ws}, {group, ws_hibernate}].
+	[
+		{group, h1},
+		{group, h1_hibernate},
+		{group, h2},
+		{group, h2_relay}
+	].
 
 %% @todo Test against HTTP/2 too.
 groups() ->
 	AllTests = ct_helper:all(?MODULE),
-	[{ws, [parallel], AllTests}, {ws_hibernate, [parallel], AllTests}].
-
-init_per_group(Name, Config) ->
+	[
+		{h1, [parallel], AllTests},
+		{h1_hibernate, [parallel], AllTests},
+		%% The websocket_deflate_false test isn't compatible with HTTP/2.
+		{h2, [parallel], AllTests -- [websocket_deflate_false]},
+		{h2_relay, [parallel], AllTests -- [websocket_deflate_false]}
+	].
+
+init_per_group(Name, Config)
+		when Name =:= h1; Name =:= h1_hibernate ->
 	cowboy_test:init_http(Name, #{
 		env => #{dispatch => init_dispatch(Name)}
+	}, Config);
+init_per_group(Name, Config)
+		when Name =:= h2; Name =:= h2_relay ->
+	cowboy_test:init_http2(Name, #{
+		enable_connect_protocol => true,
+		env => #{dispatch => init_dispatch(Name)}
 	}, Config).
 
 end_per_group(Name, _) ->
@@ -42,25 +61,27 @@ end_per_group(Name, _) ->
 %% Dispatch configuration.
 
 init_dispatch(Name) ->
-	RunOrHibernate = case Name of
-		ws -> run;
-		ws_hibernate -> hibernate
+	InitialState = case Name of
+		h1_hibernate -> #{run_or_hibernate => hibernate};
+		h2_relay -> #{run_or_hibernate => run, data_delivery => relay};
+		_ -> #{run_or_hibernate => run}
 	end,
 	cowboy_router:compile([{'_', [
-		{"/init", ws_init_commands_h, RunOrHibernate},
-		{"/handle", ws_handle_commands_h, RunOrHibernate},
-		{"/info", ws_info_commands_h, RunOrHibernate},
-		{"/trap_exit", ws_init_h, RunOrHibernate},
-		{"/active", ws_active_commands_h, RunOrHibernate},
-		{"/deflate", ws_deflate_commands_h, RunOrHibernate},
-		{"/set_options", ws_set_options_commands_h, RunOrHibernate},
-		{"/shutdown_reason", ws_shutdown_reason_commands_h, RunOrHibernate}
+		{"/init", ws_init_commands_h, InitialState},
+		{"/handle", ws_handle_commands_h, InitialState},
+		{"/info", ws_info_commands_h, InitialState},
+		{"/trap_exit", ws_init_h, InitialState},
+		{"/active", ws_active_commands_h, InitialState},
+		{"/deflate", ws_deflate_commands_h, InitialState},
+		{"/set_options", ws_set_options_commands_h, InitialState},
+		{"/shutdown_reason", ws_shutdown_reason_commands_h, InitialState}
 	]}]).
 
 %% Support functions for testing using Gun.
 
 gun_open_ws(Config, Path, Commands) ->
-	ConnPid = gun_open(Config),
+	ConnPid = gun_open(Config, #{http2_opts => #{notify_settings_changed => true}}),
+	do_await_enable_connect_protocol(config(protocol, Config), ConnPid),
 	StreamRef = gun:ws_upgrade(ConnPid, Path, [
 		{<<"x-commands">>, base64:encode(term_to_binary(Commands))}
 	]),
@@ -75,6 +96,13 @@ gun_open_ws(Config, Path, Commands) ->
 		error(timeout)
 	end.
 
+do_await_enable_connect_protocol(http, _) ->
+	ok;
+do_await_enable_connect_protocol(http2, ConnPid) ->
+	{notify, settings_changed, #{enable_connect_protocol := true}}
+		= gun:await(ConnPid, undefined), %% @todo Maybe have a gun:await/1?
+	ok.
+
 receive_ws(ConnPid, StreamRef) ->
 	receive
 		{gun_ws, ConnPid, StreamRef, Frame} ->
@@ -123,7 +151,14 @@ websocket_info_invalid(Config) ->
 do_invalid(Config, Path) ->
 	{ok, ConnPid, StreamRef} = gun_open_ws(Config, Path, bad),
 	ensure_handle_is_called(ConnPid, StreamRef, Path),
-	gun_down(ConnPid).
+	case config(protocol, Config) of
+		%% HTTP/1.1 closes the connection.
+		http -> gun_down(ConnPid);
+		%% HTTP/2 terminates the stream.
+		http2 ->
+			receive {gun_error, ConnPid, StreamRef, {stream_error, internal_error, _}} -> ok
+			after 500 -> error(timeout) end
+	end.
 
 websocket_init_one_frame(Config) ->
 	doc("A single frame is received when websocket_init/1 returns it as a command."),
@@ -223,8 +258,12 @@ websocket_active_false(Config) ->
 	doc("The {active, false} command stops receiving data from the socket. "
 		"The {active, true} command reenables it."),
 	{ok, ConnPid, StreamRef} = gun_open_ws(Config, "/active", []),
+	%% We must exhaust the HTTP/2 flow control window
+	%% otherwise the frame will be received even if active mode is disabled.
+	gun:ws_send(ConnPid, StreamRef, {binary, <<0:100000/unit:8>>}),
 	gun:ws_send(ConnPid, StreamRef, {text, <<"Not received until the handler enables active again.">>}),
 	{error, timeout} = receive_ws(ConnPid, StreamRef),
+	{ok, {binary, _}} = receive_ws(ConnPid, StreamRef),
 	{ok, {text, <<"Not received until the handler enables active again.">>}}
 		= receive_ws(ConnPid, StreamRef),
 	ok.
@@ -271,7 +310,8 @@ websocket_deflate_ignore_if_not_negotiated(Config) ->
 websocket_set_options_idle_timeout(Config) ->
 	doc("The idle_timeout option can be modified using the "
 		"command {set_options, Opts} at runtime."),
-	ConnPid = gun_open(Config),
+	ConnPid = gun_open(Config, #{http2_opts => #{notify_settings_changed => true}}),
+	do_await_enable_connect_protocol(config(protocol, Config), ConnPid),
 	StreamRef = gun:ws_upgrade(ConnPid, "/set_options"),
 	receive
 		{gun_upgrade, ConnPid, StreamRef, [<<"websocket">>], _} ->
@@ -299,7 +339,8 @@ websocket_set_options_idle_timeout(Config) ->
 websocket_set_options_max_frame_size(Config) ->
 	doc("The max_frame_size option can be modified using the "
 		"command {set_options, Opts} at runtime."),
-	ConnPid = gun_open(Config),
+	ConnPid = gun_open(Config, #{http2_opts => #{notify_settings_changed => true}}),
+	do_await_enable_connect_protocol(config(protocol, Config), ConnPid),
 	StreamRef = gun:ws_upgrade(ConnPid, "/set_options"),
 	receive
 		{gun_upgrade, ConnPid, StreamRef, [<<"websocket">>], _} ->
@@ -334,7 +375,8 @@ websocket_set_options_max_frame_size(Config) ->
 websocket_shutdown_reason(Config) ->
 	doc("The command {shutdown_reason, any()} can be used to "
 		"change the shutdown reason of a Websocket connection."),
-	ConnPid = gun_open(Config),
+	ConnPid = gun_open(Config, #{http2_opts => #{notify_settings_changed => true}}),
+	do_await_enable_connect_protocol(config(protocol, Config), ConnPid),
 	StreamRef = gun:ws_upgrade(ConnPid, "/shutdown_reason", [
 		{<<"x-test-pid">>, pid_to_list(self())}
 	]),