Granular P2P logging

[heifner]

Currently debug level logging for net_plugin_impl is a huge amount of logging. Seems it would be beneficial to break up the P2P logging into:

• p2p_trx - transaction received/sent logging
• p2p_block - block/block_header received/sent logging
• p2p_msg - all p2p messages received/sent (except block/trx)
• p2p_conn - connections related logging, e.g. connect/disconnect

[bhazzard]

Tentatively targeting v1.3.0-rc1, pending a solution for backwards compatibility with logging configs v1.2.0 and earlier.

[heifner]

fc::logger already supports a hierarchy of loggers via parent specification. The feature currently doesn't actually work because the associated additivity flag is not being set from the config loading. Fixing the additivity flag would be trivial.

The parent specification allows us to specify something like:

    },{
      "name": "net_plugin_impl",
      "level": "info",
      "enabled": true,
      "additivity": false,
      "appenders": [
        "stderr",
        "net"
      ]
    },{
      "name": "p2p_trx",
      "level": "info",
      "enabled": true,
      "additivity": true,
      "parent": "net_plugin_impl"
    },{

This doesn't provide the backwards compatibility as parent has to be specified in the logging.json. However, this could be defaulted in code:

   void net_plugin::handle_sighup() {
      fc::logger::update( logger_name, logger );
      fc::logger::update_with_default( "p2p_trx", trx_logger, logger_name );
   }

Where fc::logger::update_with_default is very similar to existing update_logger but uses default_name as the default instead of DEFAULT_LOGGER.

   void log_config::update_logger( const std::string& name, logger& log ) {
      update_with_default(name, log, DEFAULT_LOGGER);
   }

   void log_config::update_logger_with_default( const std::string& name, logger& log, const std::string& default_name ) {
      std::lock_guard g( log_config::get().log_mutex );
      if( log_config::get().logger_map.find( name ) != log_config::get().logger_map.end() ) {
         log = log_config::get().logger_map[name];
      } else {
         // no entry for logger, so setup with default logger if it exists, otherwise do nothing since default logger not configured
         if( log_config::get().logger_map.find( default_name ) != log_config::get().logger_map.end() ) {
            log = log_config::get().logger_map[default_name];
            log_config::get().logger_map.emplace( name, log );
         }
      }
   }