nodeos 输出log方式

https://github.com/EOSIO/fc/blob/a6f94bae0b2b4a0b68dc1db2677331cafa4716a5/src/log/logger_config.cpp#L24

 bool configure_logging( const logging_config& cfg )
   {
      try {
      static bool reg_console_appender = appender::register_appender<console_appender>( "console" );
      static bool reg_gelf_appender = appender::register_appender<gelf_appender>( "gelf" );
      get_logger_map().clear();
      get_appender_map().clear();

支持输出到 console 和 gelf 两种方式

gelf
https://sourcegraph.com/github.com/EOSIO/fc@a6f94bae0b2b4a0b68dc1db2677331cafa4716a5/-/blob/include/fc/log/gelf_appender.hpp

namespace fc 
{
  // Log appender that sends log messages in JSON format over UDP
  // https://www.graylog2.org/resources/gelf/specification
  class gelf_appender final : public appender 
  {
  public:
    struct config 
    {
      string endpoint = "127.0.0.1:12201";
      string host = "fc"; // the name of the host, source or application that sent this message (just passed through to GELF server)
    };

类似 https://github.com/mattwcole/gelf-extensions-logging