Merge pull request #78 from tomas-abrahamsson/fd-socket-opt

Support the fd socket option when listening

Author: tsloughter

src/grpcbox_socket.erl

@@ -30,7 +30,8 @@ init([Pool, ListenOpts, PoolOpts]) ->
     %% Trapping exit so can close socket in terminate/2
     _ = process_flag(trap_exit, true),
     Opts = [{active, false}, {mode, binary}, {packet, raw}, {ip, IPAddress} | SocketOpts],
-    case gen_tcp:listen(Port, Opts) of
+    {LPort, LOpts} = maybe_adjust_port_opts_for_fdopt(Port, Opts),
+    case gen_tcp:listen(LPort, LOpts) of
         {ok, Socket} ->
             %% acceptor could close the socket if there is a problem
             MRef = monitor(port, Socket),
@@ -40,6 +41,17 @@ init([Pool, ListenOpts, PoolOpts]) ->
             {stop, Reason}
     end.
 
+maybe_adjust_port_opts_for_fdopt(Port, Opts) ->
+    case lists:keymember(fd, 1, Opts) of
+        true ->
+            %% If an already opened (bound) file descriptor is passed,
+            %% we must not set port or ip, or there will be an error
+            %% when it would have gotten bound again.
+            {0, lists:keydelete(ip, 1, Opts)};
+        false ->
+            {Port, Opts}
+    end.
+
 handle_call(Req, _, State) ->
     {stop, {bad_call, Req}, State}.
 

test/grpcbox_SUITE.erl

@@ -13,6 +13,7 @@ groups() ->
     [{ssl, [], [unary_authenticated]},
      {tcp, [], [unary_no_auth, multiple_servers,
                 unary_garbage_collect_streams]},
+     {socket_options, [], [fd_socket_option]},
      {concurrent, [{repeat_until_any_fail, 5}], [unary_concurrent]},
      {negative_tests, [], [unimplemented, closed_stream, generate_error, streaming_generate_error]},
      {negative_ssl, [], [unauthorized]},
@@ -22,6 +23,7 @@ groups() ->
 all() ->
     [{group, ssl},
      {group, tcp},
+     {group, socket_options},
      {group, concurrent},
      {group, negative_tests},
      {group, negative_ssl},
@@ -75,6 +77,14 @@ init_per_group(tcp, Config) ->
                                              transport_opts => #{}}]),
     application:ensure_all_started(grpcbox),
     Config;
+init_per_group(socket_options, Config) ->
+    application:set_env(grpcbox, client, #{channels => [{default_channel, [{http, "localhost", 8080, []}],
+                                                         #{}}]}),
+    application:set_env(grpcbox, servers, [#{grpc_opts => #{service_protos => [route_guide_pb],
+                                                            services => #{'routeguide.RouteGuide' =>
+                                                                              routeguide_route_guide}},
+                                             transport_opts => #{}}]),
+    Config;
 init_per_group(concurrent, Config) ->
     application:set_env(grpcbox, client, #{channels => [{default_channel, [{http, "localhost", 8080, []}],
                                                          #{}}]}),
@@ -312,6 +322,8 @@ end_per_testcase(multiple_servers, _Config) ->
     ok;
 end_per_testcase(unary_garbage_collect_streams, _Config) ->
     ok;
+end_per_testcase(fd_socket_option, _Config) ->
+    ok;
 end_per_testcase(unary_concurrent, _Config) ->
     ok;
 end_per_testcase(unimplemented, _Config) ->
@@ -564,6 +576,24 @@ multiple_servers(_Config) ->
     unary(_Config),
     unary(_Config).
 
+fd_socket_option(_Config) ->
+    %% Use the fd option to dynamically select a free port
+    {ok, Ip} = inet:getaddr("localhost", inet),
+    {ok, Sock} = gen_tcp:listen(0, [{ip, Ip}, inet]),
+    {ok, Fd} = inet:getfd(Sock),
+    {ok, {_ListenIp, ListenPort}} = inet:sockname(Sock),
+    application:set_env(grpcbox, client, #{channels => [{default_channel,
+                                                         [{http, "localhost", ListenPort, []}], #{}}]}),
+
+    application:set_env(grpcbox, servers, [#{grpc_opts => #{service_protos => [route_guide_pb],
+                                                            services => #{'routeguide.RouteGuide' =>
+                                                                              routeguide_route_guide}},
+                                             listen_opts => #{socket_options => [{fd, Fd}]}}]),
+    {ok, _} = application:ensure_all_started(grpcbox),
+    unary(_Config),
+    application:stop(grpcbox),
+    gen_tcp:close(Sock).
+
 unary_concurrent(Config) ->
     Nrs = lists:seq(1,100),
     ParentPid = self(),