Add a script to simulate heavy lobby traffic

Plus a bunch of changes which were necessary for the script to work:
* The "simulate lobby activity" plugin now exits when the server is shut
  down.
* The plugin now uses wesnoth.random() for random number generation.
  Math.random() uses a fixed seed, which would make all the clients
  perform the exact same actions.
* Exposed wesnoth.random() to plugins to allow the change above.
* --nogui no longer implies --wconsole on Windows. With implied --wconsole
  the clients attached themselves to the standard output of the Python
  script, which made it impossible to see the output of the script itself.

simulate-lobby-activity.lua

@@ -21,10 +21,22 @@ local function create_game(context)
   context.create({})
 end
 
+local function exit_game(context)
+  local events, info
+
+  repeat
+    context.quit({})
+    events, context, info = coroutine.yield()
+  until info.name == "titlescreen"
+
+  context.exit({code = 0})
+  coroutine.yield()
+end
+
 return function()
   local events, context, info
 
-  wesnoth.preferences.new_lobby = true
+  wesnoth.preferences.new_mp_ui = true
 
   repeat
     events, context, info = coroutine.yield()
@@ -42,17 +54,22 @@ return function()
   -- Reached the lobby. Random delay before we start actually simulating activity.
   -- This is here to avoid a situation where activity arrives in bursts after a script
   -- has launched, say, 100 copies of Wesnoth at the same time.
-  wesnoth.delay(math.random(15000))
+  wesnoth.delay(wesnoth.random(15000))
 
   events, context, info = coroutine.yield()
 
   local in_staging = false
 
   while true do
-    if math.random() > 0.1 then
+    if info.name ~= "Multiplayer Lobby" and info.name ~= "Multiplayer Staging" then
+      -- most often, this means that the server was terminated -> stop generating traffic
+      exit_game(context)
+    end
+
+    if wesnoth.random() > 0.1 then
       -- chat message
       local messages = {"asdf", "qwerty", "zxc"}
-      context.chat({message = messages[math.random(#messages)]})
+      context.chat({message = messages[wesnoth.random(#messages)]})
     else
       -- toggle between creating a game and leaving it
       if not in_staging then

src/scripting/game_lua_kernel.cpp

@@ -654,36 +654,6 @@ int game_lua_kernel::intf_set_variable(lua_State *L)
 	return 0;
 }
 
-/**
- * Returns a random numer, same interface as math.random.
- */
-int game_lua_kernel::intf_random(lua_State *L)
-{
-	if(lua_isnoneornil(L, 1)) {
-		double r = double (random_new::generator->next_random());
-		double r_max = double (std::numeric_limits<uint32_t>::max());
-		lua_push(L, r / (r_max + 1));
-		return 1;
-	}
-	else {
-		int32_t min;
-		int32_t max;
-		if(lua_isnumber(L, 2)) {
-			min = lua_check<int32_t>(L, 1);
-			max = lua_check<int32_t>(L, 2);
-		}
-		else {
-			min = 1;
-			max = lua_check<int32_t>(L, 1);
-		}
-		if(min > max) {
-			return luaL_argerror(L, 1, "min > max");
-		}
-		lua_push(L, random_new::generator->get_random_int(min, max));
-		return 1;
-	}
-}
-
 int game_lua_kernel::intf_set_menu_item(lua_State *L)
 {
 	game_state_.get_wml_menu_items().set_item(luaL_checkstring(L, 1), luaW_checkvconfig(L,2));
@@ -4160,7 +4130,6 @@ game_lua_kernel::game_lua_kernel(game_state & gs, play_controller & pc, reports
 		{ "print",                     &dispatch<&game_lua_kernel::intf_print                      >        },
 		{ "put_recall_unit",           &dispatch<&game_lua_kernel::intf_put_recall_unit            >        },
 		{ "put_unit",                  &dispatch<&game_lua_kernel::intf_put_unit                   >        },
-		{ "random",                    &dispatch<&game_lua_kernel::intf_random                     >        },
 		{ "redraw",                    &dispatch<&game_lua_kernel::intf_redraw                     >        },
 		{ "remove_event_handler",      &dispatch<&game_lua_kernel::intf_remove_event               >        },
 		{ "remove_fog",                &dispatch2<&game_lua_kernel::intf_toggle_fog, true          >        },

src/scripting/game_lua_kernel.hpp

@@ -84,7 +84,6 @@ class game_lua_kernel : public lua_kernel_base
 	int intf_get_recall_units(lua_State *L);
 	int intf_get_variable(lua_State *L);
 	int intf_get_side_variable(lua_State *L);
-	int intf_random(lua_State *L);
 	int intf_set_variable(lua_State *L);
 	int intf_set_side_variable(lua_State *L);
 	int intf_highlight_hex(lua_State *L);

src/scripting/lua_kernel_base.cpp

@@ -21,6 +21,7 @@
 #include "game_errors.hpp"
 #include "log.hpp"
 #include "lua_jailbreak_exception.hpp"  // for tlua_jailbreak_exception
+#include "random_new.hpp"
 #include "seed_rng.hpp"
 
 #ifdef DEBUG_LUA
@@ -213,6 +214,36 @@ static int intf_name_generator(lua_State *L)
 	return 1;
 }
 
+/**
+* Returns a random numer, same interface as math.random.
+*/
+static int intf_random(lua_State *L)
+{
+	if (lua_isnoneornil(L, 1)) {
+		double r = double(random_new::generator->next_random());
+		double r_max = double(std::numeric_limits<uint32_t>::max());
+		lua_push(L, r / (r_max + 1));
+		return 1;
+	}
+	else {
+		int32_t min;
+		int32_t max;
+		if (lua_isnumber(L, 2)) {
+			min = lua_check<int32_t>(L, 1);
+			max = lua_check<int32_t>(L, 2);
+		}
+		else {
+			min = 1;
+			max = lua_check<int32_t>(L, 1);
+		}
+		if (min > max) {
+			return luaL_argerror(L, 1, "min > max");
+		}
+		lua_push(L, random_new::generator->get_random_int(min, max));
+		return 1;
+	}
+}
+
 // End Callback implementations
 
 // Template which allows to push member functions to the lua kernel base into lua as C functions, using a shim
@@ -332,6 +363,7 @@ lua_kernel_base::lua_kernel_base()
 		{ "compile_formula",          &lua_formula_bridge::intf_compile_formula},
 		{ "eval_formula",             &lua_formula_bridge::intf_eval_formula},
 		{ "name_generator",           &intf_name_generator           },
+		{ "random",                   &intf_random                   },
 		{ nullptr, nullptr }
 	};
 

src/wesnoth.cpp

@@ -956,7 +956,7 @@ int main(int argc, char** argv)
 	//       running before then if requested, so just perform a trivial search
 	//       here and let program_options ignore the switch later.
 	for(size_t k = 0; k < args.size(); ++k) {
-		if(args[k] == "--wconsole" || args[k] == "--help" || args[k] == "--nogui" || args[k] == "--logdomains" || args[k] == "--path" || args[k] == "--render-image" || args[k] == "--screenshot" || args[k] == "--data-path" || args[k] == "--userdata-path" || args[k] == "--userconfig-path" || args[k] == "--version") {
+		if(args[k] == "--wconsole" || args[k] == "--help" || args[k] == "--logdomains" || args[k] == "--path" || args[k] == "--render-image" || args[k] == "--screenshot" || args[k] == "--data-path" || args[k] == "--userdata-path" || args[k] == "--userconfig-path" || args[k] == "--version") {
 			lg::enable_native_console_output();
 			break;
 		}

utils/simulate_lobby_traffic.py

@@ -0,0 +1,59 @@
+# This script launches wesnothd, followed by 20 copies of wesnoth running the simulate-lobby-activity.lua plugin.
+# The idea is to use the script to simulate a high amount of lobby traffic, e.g. for performance testing.
+
+import subprocess
+from subprocess import DEVNULL
+import os
+import os.path
+import sys
+import time
+
+PORT = 56321
+NUM_CLIENTS = 20
+EXIT_WAIT_TIME = 20.0
+
+def is_in_path(filename):
+  for d in os.get_exec_path():
+    if os.path.exists(os.path.join(d, filename)):
+      return True
+  return False
+
+if (os.name == "nt" and not is_in_path("SDL2.dll")):
+  # Launching Wesnoth is not going to succeed
+  sys.exit("Error: SDL2.dll is not in PATH. This suggests that you haven't added the external\\dll directory to your PATH.")
+
+print("Launching processes... ", end="")
+
+# Change the working directory to the parent directory of the directory where this script resides
+os.chdir(os.path.dirname(os.path.dirname(__file__)))
+
+# Wesnoth restarts itself on launch if OMP_WAIT_POLICY isn't set. That's problematic because it makes it impossible to poll
+# when the client processes terminate. Thus, set OMP_WAIT_POLICY.
+os.environ["OMP_WAIT_POLICY"] = "PASSIVE"
+
+# Launch the server
+server = subprocess.Popen(("wesnothd", "-p", str(PORT)), -1, None, DEVNULL, DEVNULL, DEVNULL)
+
+# Launch the clients
+clients = set()
+for i in range(NUM_CLIENTS):
+  clients.add(subprocess.Popen(("wesnoth", "--plugin=simulate-lobby-activity.lua", "--server=localhost:%d" % PORT, "--username=%d" % i, "--nogui"),
+    -1, None, DEVNULL, DEVNULL, DEVNULL))
+
+input("done.\nPress Enter when you want to terminate all processes.")
+
+server.terminate()
+
+print("Waiting for clients to terminate...")
+waiting_start_time = time.monotonic()
+while len(clients) > 0 and time.monotonic() < waiting_start_time + EXIT_WAIT_TIME:
+  time.sleep(1.0)
+  clients_copy = list(clients)
+  for c in clients_copy:
+    if c.poll() != None:
+      # The process has terminated, remove it from the set.
+      clients.remove(c)
+
+# Make sure that we get rid of the remaining processes
+for c in clients:
+  c.kill()