g3log/docs/API_custom_formatting.md

introduction | detailed information | Configure & Build | API description | Custom log formatting

Custom LOG formatting

Overriding the Default File Sink's file header

The default file header can be customized in the default file sink in calling

   FileSink::overrideLogHeader(std::string);

Overriding the Default FileSink's log formatting

The default log formatting is defined in LogMessage.hpp

   static std::string DefaultLogDetailsToString(const LogMessage& msg);

Adding thread ID to the log formatting

An "all details" log formatting function is also defined - this one also adds the "calling thread's ID"

   static std::string FullLogDetailsToString(const LogMessage& msg);

Override default sink log formatting

For convenience the Default sink has a function for doing exactly this

  void overrideLogDetails(LogMessage::LogDetailsFunc func);

Example code for replacing the default log formatting for "full details" formatting (it adds thread ID)

   auto worker = g3::LogWorker::createLogWorker();
   auto handle= worker->addDefaultLogger(argv[0], path_to_log_file);
   g3::initializeLogging(worker.get());
   handle->call(&g3::FileSink::overrideLogDetails, &LogMessage::FullLogDetailsToString);

See test_message.cpp for details and testing

Example code for overloading the formatting of a custom sink. The log formatting function will be passed into the LogMessage::toString(...) this will override the default log formatting

Example

namespace {
      std::string MyCustomFormatting(const LogMessage& msg) {
        ... how you want it ...
      }
    }

   void MyCustomSink::ReceiveLogEntry(LogMessageMover message) {
      std::string formatted = message.get().toString(&MyCustomFormatting) << std::flush;
   }
...
...
 auto worker = g3::LogWorker::createLogWorker();
 auto sinkHandle = worker->addSink(std::make_unique<MyCustomSink>(),
                                     &MyCustomSink::ReceiveLogMessage);
 // ReceiveLogMessage(...) will used the custom formatting function "MyCustomFormatting(...)
    

introduction | detailed information | Configure & Build | API description | Custom log formatting