lua_gc is called periodicaly in order to clean broker events owned by…

… lua (#1119)

broker/lua/inc/com/centreon/broker/lua/broker_event.hh

@@ -48,13 +48,25 @@ namespace lua {
  *
  */
 class broker_event {
+  struct gc_info {
+    gc_info() : _broker_event_cpt(0), _last_full_gc(time(nullptr)) {}
+
+    unsigned _broker_event_cpt;
+    time_t _last_full_gc;
+  };
+
+  static std::map<const lua_State*, gc_info> _gc_info;
+  static std::mutex _gc_info_m;
+
+  static int l_broker_event_destructor(lua_State* L);
  public:
   static void broker_event_reg(lua_State* L);
   static void create(lua_State* L, std::shared_ptr<io::data> e);
   static void create_as_table(lua_State* L, const io::data& e);
+  static void lua_close(const lua_State* L);
 };
 }  // namespace lua
 
-}
+}  // namespace com::centreon::broker
 
 #endif  // !CCB_LUA_BROKER_EVENT_HH

broker/lua/src/broker_event.cc

@@ -22,6 +22,7 @@
 #include "com/centreon/broker/io/data.hh"
 #include "com/centreon/broker/io/protobuf.hh"
 #include "com/centreon/broker/mapping/entry.hh"
+#include "com/centreon/broker/multiplexing/muxer.hh"
 #include "com/centreon/exceptions/msg_fmt.hh"
 
 using namespace com::centreon::broker;
@@ -32,6 +33,8 @@ static void _write_item(lua_State* L,
                         const google::protobuf::Message* p,
                         const google::protobuf::FieldDescriptor* f);
 
+std::map<const lua_State*, broker_event::gc_info> broker_event::_gc_info;
+std::mutex broker_event::_gc_info_m;
 /**
  *  The Lua broker_event constructor
  *
@@ -48,6 +51,32 @@ void broker_event::create(lua_State* L, std::shared_ptr<io::data> e) {
 
   luaL_getmetatable(L, "broker_event");
   lua_setmetatable(L, -2);
+  bool have_to_gc_collect = false;
+  {
+    std::lock_guard l(_gc_info_m);
+
+    /*In V2, lua stores only a userdata that contains a shared_ptr of event
+     * (16 bytes). So garbage collector don't see amount of memory used by
+     * events.
+     * So we need to call garbage collector ourselves to reduce memory
+     * consumption
+     * So we call at least gc every minute or
+     * at most every 10s if lua own more than
+     * com::centreon::broker::multiplexing::muxer::event_queue_max_size() events
+     * */
+    time_t now = time(nullptr);
+    gc_info& gc_inf = _gc_info[L];
+    if ((++gc_inf._broker_event_cpt > com::centreon::broker::multiplexing::
+                                          muxer::event_queue_max_size() &&
+         gc_inf._last_full_gc + 10 < now) ||
+        (gc_inf._last_full_gc + 60 < now)) {
+      gc_inf._last_full_gc = now;
+      have_to_gc_collect = true;
+    }
+  }
+  if (have_to_gc_collect) {
+    lua_gc(L, LUA_GCCOLLECT, 0);
+  }
 }
 
 static void _message_to_table(lua_State* L,
@@ -344,12 +373,18 @@ void broker_event::create_as_table(lua_State* L, const io::data& d) {
  *
  *  @return 0
  */
-static int l_broker_event_destructor(lua_State* L) {
+int broker_event::l_broker_event_destructor(lua_State* L) {
   void* ptr = luaL_checkudata(L, 1, "broker_event");
 
   if (ptr) {
     auto event = static_cast<std::shared_ptr<io::data>*>(ptr);
     event->reset();
+    std::lock_guard l(_gc_info_m);
+
+    gc_info& gc_inf = _gc_info[L];
+    if (gc_inf._broker_event_cpt > 0) {
+      --gc_inf._broker_event_cpt;
+    }
   }
   return 0;
 }
@@ -758,3 +793,13 @@ void broker_event::broker_event_reg(lua_State* L) {
 
   lua_setglobal(L, name);
 }
+
+/**
+ * @brief when a lua_State is closed we clean _gc_info
+ *
+ * @param The Lua interpreter as a lua_State*
+ */
+void broker_event::lua_close(const lua_State* L) {
+  std::lock_guard l(_gc_info_m);
+  _gc_info.erase(L);
+}

broker/lua/src/luabinding.cc

@@ -91,6 +91,7 @@ int32_t luabinding::stop() {
   if (_L) {
     retval = flush();
     lua_close(_L);
+    broker_event::lua_close(_L);
     _L = nullptr;
   }
   return retval;