feat: enable TCP keepalive and nodelay on all connections (DRIVERS-383)

src/connection/mc_worker_logic.erl

@@ -139,9 +139,11 @@ process_op_msg_response(From) ->
 %% @private
 do_connect(Host, Port, Timeout, true, Opts) ->
   {ok, _} = application:ensure_all_started(ssl),
-  ssl:connect(Host, Port, [binary, {active, true}, {packet, raw}] ++ Opts, Timeout);
+  ssl:connect(Host, Port, [binary, {active, true}, {packet, raw},
+                           {keepalive, true}, {nodelay, true}] ++ Opts, Timeout);
 do_connect(Host, Port, Timeout, false, _) ->
-  gen_tcp:connect(Host, Port, [binary, {active, true}, {packet, raw}], Timeout).
+  gen_tcp:connect(Host, Port, [binary, {active, true}, {packet, raw},
+                               {keepalive, true}, {nodelay, true}], Timeout).
 
 do_srv_connect(Srv, Timeout, SSL, SslOpts) ->
   {ok, Seeds} = mc_utils:get_srv_seeds(Srv),

test/tcp_keepalive_SUITE.erl

@@ -0,0 +1,173 @@
+-module(tcp_keepalive_SUITE).
+
+-include_lib("proper/include/proper.hrl").
+-include_lib("common_test/include/ct.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+-compile([export_all, nowarn_export_all]).
+
+%%====================================================================
+%% CT Callbacks
+%%====================================================================
+
+all() ->
+  [
+    prop_keepalive_nodelay_enabled,
+    prop_existing_options_preserved,
+    prop_ssl_user_option_override,
+    unit_keepalive_concrete,
+    unit_keepalive_ping
+  ].
+
+init_per_suite(Config) ->
+  application:ensure_all_started(mongodb),
+  [{database, <<"test">>} | Config].
+
+end_per_suite(_Config) ->
+  ok.
+
+%%====================================================================
+%% Property Tests
+%%====================================================================
+prop_keepalive_nodelay_enabled(Config) ->
+  Database = ?config(database, Config),
+
+  Property = ?FORALL(Timeout, range(1000, 30000),
+    begin
+      try
+        {ok, Conn} = mc_worker_api:connect([{database, Database}, {timeout, Timeout}]),
+
+        %% Extract socket from mc_worker gen_server state
+        WorkerState = sys:get_state(Conn),
+        Socket = element(2, WorkerState),
+
+        %% Query socket options for keepalive and nodelay
+        {ok, Opts} = inet:getopts(Socket, [keepalive, nodelay]),
+
+        mc_worker_api:disconnect(Conn),
+
+        %% Assert both keepalive and nodelay are true
+        lists:member({keepalive, true}, Opts) andalso
+        lists:member({nodelay, true}, Opts)
+      catch
+        Class:Error:Stack ->
+          ct:log("Property 1 failed: ~p:~p~n~p", [Class, Error, Stack]),
+          false
+      end
+    end),
+
+  true = proper:quickcheck(Property, [{numtests, 100}, {to_file, user}]),
+  ok.
+
+prop_existing_options_preserved(Config) ->
+  Database = ?config(database, Config),
+
+  Property = ?FORALL(Timeout, range(1000, 30000),
+    begin
+      try
+        {ok, Conn} = mc_worker_api:connect([{database, Database}, {timeout, Timeout}]),
+
+        %% Extract socket from mc_worker gen_server state
+        WorkerState = sys:get_state(Conn),
+        Socket = element(2, WorkerState),
+
+        %% Query socket options for active and packet
+        {ok, Opts} = inet:getopts(Socket, [active, packet]),
+
+        mc_worker_api:disconnect(Conn),
+
+        %% Assert existing options are preserved alongside keepalive/nodelay
+        %% Note: inet:getopts returns {packet, 0} which is equivalent to {packet, raw}
+        lists:member({active, true}, Opts) andalso
+        lists:member({packet, 0}, Opts)
+      catch
+        Class:Error:Stack ->
+          ct:log("Property 2 failed: ~p:~p~n~p", [Class, Error, Stack]),
+          false
+      end
+    end),
+
+  true = proper:quickcheck(Property, [{numtests, 100}, {to_file, user}]),
+  ok.
+
+prop_ssl_user_option_override(_Config) ->
+  %% Skip if SSL MongoDB is not available
+  try mc_worker_api:connect([{database, <<"test">>}, {ssl, true},
+                             {ssl_opts, [{verify, verify_none}]}]) of
+    {ok, TestConn} ->
+      mc_worker_api:disconnect(TestConn),
+      run_ssl_override_property();
+    {error, _} ->
+      {skip, "SSL-enabled MongoDB not available"}
+  catch
+    _:_ ->
+      {skip, "SSL-enabled MongoDB not available"}
+  end.
+
+run_ssl_override_property() ->
+  Property = ?FORALL({Keepalive, Nodelay}, {boolean(), boolean()},
+    begin
+      try
+        SslOpts = [{verify, verify_none},
+                   {keepalive, Keepalive},
+                   {nodelay, Nodelay}],
+        {ok, Conn} = mc_worker_api:connect([{database, <<"test">>},
+                                            {ssl, true},
+                                            {ssl_opts, SslOpts}]),
+
+        %% Extract SSL socket from mc_worker gen_server state
+        WorkerState = sys:get_state(Conn),
+        Socket = element(2, WorkerState),
+
+        %% For SSL sockets, use ssl:getopts/2
+        {ok, Opts} = ssl:getopts(Socket, [keepalive, nodelay]),
+
+        mc_worker_api:disconnect(Conn),
+
+        %% Assert user-provided values take precedence over defaults
+        lists:member({keepalive, Keepalive}, Opts) andalso
+        lists:member({nodelay, Nodelay}, Opts)
+      catch
+        Class:Error:Stack ->
+          ct:log("Property 3 failed: ~p:~p~n~p", [Class, Error, Stack]),
+          false
+      end
+    end),
+
+  true = proper:quickcheck(Property, [{numtests, 100}, {to_file, user}]),
+  ok.
+
+
+%%====================================================================
+%% Unit Tests
+%%====================================================================
+unit_keepalive_concrete(Config) ->
+  Database = ?config(database, Config),
+  {ok, Conn} = mc_worker_api:connect([{database, Database}]),
+
+  %% Extract socket from mc_worker gen_server state
+  WorkerState = sys:get_state(Conn),
+  Socket = element(2, WorkerState),
+
+  %% Query socket options
+  {ok, Opts} = inet:getopts(Socket, [keepalive, nodelay]),
+
+  %% Assert keepalive and nodelay are both true
+  ?assert(lists:member({keepalive, true}, Opts)),
+  ?assert(lists:member({nodelay, true}, Opts)),
+
+  mc_worker_api:disconnect(Conn),
+  ok.
+
+%% Integration sanity check: connection with keepalive can execute a ping command
+%% Validates: Requirements 1.1, 1.2, 5.1, 5.2
+unit_keepalive_ping(Config) ->
+  Database = ?config(database, Config),
+  {ok, Conn} = mc_worker_api:connect([{database, Database}]),
+
+  %% Execute ping command
+  Result = mc_worker_api:command(Conn, bson:document([{ping, 1}])),
+  ?assertEqual({true, #{<<"ok">> => 1.0}}, Result),
+
+  mc_worker_api:disconnect(Conn),
+  ok.