Periodically re-check addresses of seed nodes

libraries/net/node.cpp

@@ -483,6 +483,43 @@ namespace graphene { namespace net { namespace detail {
       //  _retrigger_connect_loop_promise->set_value();
     }
 
+   void node_impl::update_seed_nodes_task()
+   {
+      VERIFY_CORRECT_THREAD();
+
+      try
+      {
+         dlog("Starting an iteration of update_seed_nodes loop.");
+         for( const std::string& endpoint_string : _seed_nodes )
+         {
+            resolve_seed_node_and_add( endpoint_string );
+         }
+         dlog("Done an iteration of update_seed_nodes loop.");
+      }
+      catch (const fc::canceled_exception&)
+      {
+        throw;
+      }
+      FC_CAPTURE_AND_LOG( (_seed_nodes) )
+
+      schedule_next_update_seed_nodes_task();
+   }
+
+   void node_impl::schedule_next_update_seed_nodes_task()
+   {
+      VERIFY_CORRECT_THREAD();
+
+      if( _node_is_shutting_down )
+         return;
+
+      if( _update_seed_nodes_loop_done.valid() && _update_seed_nodes_loop_done.canceled() )
+         return;
+
+      _update_seed_nodes_loop_done = fc::schedule( [this]() { update_seed_nodes_task(); },
+                                                   fc::time_point::now() + fc::hours(3),
+                                                   "update_seed_nodes_loop" );
+   }
+
     bool node_impl::have_already_received_sync_item( const item_hash_t& item_hash )
     {
       VERIFY_CORRECT_THREAD();
@@ -3762,6 +3799,20 @@ namespace graphene { namespace net { namespace detail {
         wlog( "Exception thrown while terminating Fetch updated peer lists loop, ignoring" );
       }
 
+      try
+      {
+        _update_seed_nodes_loop_done.cancel_and_wait("node_impl::close()");
+        dlog("Update seed nodes loop terminated");
+      }
+      catch ( const fc::exception& e )
+      {
+        wlog( "Exception thrown while terminating Update seed nodes loop, ignoring: ${e}", ("e", e) );
+      }
+      catch (...)
+      {
+        wlog( "Exception thrown while terminating Update seed nodes loop, ignoring" );
+      }
+
       try
       {
         _bandwidth_monitor_loop_done.cancel_and_wait("node_impl::close()");
@@ -4166,6 +4217,7 @@ namespace graphene { namespace net { namespace detail {
 
       assert(!_accept_loop_complete.valid() &&
              !_p2p_network_connect_loop_done.valid() &&
+             !_update_seed_nodes_loop_done.valid() &&
              !_fetch_sync_items_loop_done.valid() &&
              !_fetch_item_loop_done.valid() &&
              !_advertise_inventory_loop_done.valid() &&
@@ -4183,6 +4235,7 @@ namespace graphene { namespace net { namespace detail {
       _fetch_updated_peer_lists_loop_done = fc::async([=](){ fetch_updated_peer_lists_loop(); }, "fetch_updated_peer_lists_loop");
       _bandwidth_monitor_loop_done = fc::async([=](){ bandwidth_monitor_loop(); }, "bandwidth_monitor_loop");
       _dump_node_status_task_done = fc::async([=](){ dump_node_status_task(); }, "dump_node_status_task");
+      schedule_next_update_seed_nodes_task();
     }
 
     void node_impl::add_node(const fc::ip::endpoint& ep)
@@ -4201,9 +4254,17 @@ namespace graphene { namespace net { namespace detail {
     }
 
    void node_impl::add_seed_node(const std::string& endpoint_string)
+   {
+      VERIFY_CORRECT_THREAD();
+      _seed_nodes.insert( endpoint_string );
+      resolve_seed_node_and_add( endpoint_string );
+   }
+
+   void node_impl::resolve_seed_node_and_add(const std::string& endpoint_string)
    {
       VERIFY_CORRECT_THREAD();
       std::vector<fc::ip::endpoint> endpoints;
+      ilog("Resolving seed node ${endpoint}", ("endpoint", endpoint_string));
       try
       {
          endpoints = graphene::net::node::resolve_string_to_ip_endpoints(endpoint_string);
@@ -5125,6 +5186,7 @@ namespace graphene { namespace net { namespace detail {
 
   } // end namespace detail
 
+   // TODO move this function to impl class
    std::vector<fc::ip::endpoint> node::resolve_string_to_ip_endpoints(const std::string& in)
    {
       try

libraries/net/node_impl.hxx

@@ -337,6 +337,14 @@ class node_impl : public peer_connection_delegate
 
       std::list<fc::future<void> > _handle_message_calls_in_progress;
 
+      /// used by the task that checks whether addresses of seed nodes have been updated
+      // @{
+      boost::container::flat_set<std::string> _seed_nodes;
+      fc::future<void> _update_seed_nodes_loop_done;
+      void update_seed_nodes_task();
+      void schedule_next_update_seed_nodes_task();
+      // @}
+
       node_impl(const std::string& user_agent);
       virtual ~node_impl();
 
@@ -483,6 +491,7 @@ class node_impl : public peer_connection_delegate
       void connect_to_p2p_network();
       void add_node( const fc::ip::endpoint& ep );
       void add_seed_node( const std::string& seed_string );
+      void resolve_seed_node_and_add( const std::string& seed_string );
       void initiate_connect_to(const peer_connection_ptr& peer);
       void connect_to_endpoint(const fc::ip::endpoint& ep);
       void listen_on_endpoint(const fc::ip::endpoint& ep , bool wait_if_not_available);