/// <summary>
/// Maps Episerver.Logging.Level enum value to NLog.LogLevel. For unknown Episerver.Logging.Level returns NLog.LogLevel.Info log level.
/// </summary>
/// <param name="level">Episerver.Logging.Level enum value</param>
/// <returns>Mapped NLog.LogLevel</returns>
public static LogLevel MapEpiserverLogLevel(Epilog.Level level)
{
switch (level)
{
case Epilog.Level.Trace:
return(LogLevel.Trace);
case Epilog.Level.Debug:
return(LogLevel.Debug);
case Epilog.Level.Information:
return(LogLevel.Info);
case Epilog.Level.Warning:
return(LogLevel.Warn);
case Epilog.Level.Error:
return(LogLevel.Error);
case Epilog.Level.Critical:
return(LogLevel.Fatal);
default:
// don't throw exception but default to info level if unknown level
return(LogLevel.Info);
}
}
/// <summary>
/// Writes to log if the used log level is enabled.
/// </summary>
public void Log <TState, TException>(Epilog.Level level, TState state, TException exception, Func <TState, TException, string> messageFormatter, Type boundaryType) where TException : Exception
{
// currently the episerver logging extensions [public static void Log(this ILogger logger, Level level, string message)] checks the log message with IsNullOrEmpty and don't log if true
LogLevel logLevel = MapEpiserverLogLevel(level);
// we are not calling the IsEnabled because the underlying implementations will do that
// and the message is extracted when it is sure it will be actually logged
// side note: the extension used here checks should the message be logged and then calls other method which in turn checks should the message be logged ;)
// so even if we call directly the actual logging method we need to then call here the IsEnabled before creating the log message, so still two calls to IsEnabled(level)
_logger.Log(logLevel, exception, () => {
string logMessage = null;
if (messageFormatter != null)
{
try
{
logMessage = messageFormatter(state, exception);
}
catch (Exception)
{
}
}
// just a fallback to get something to the log in case the messageFormatter is null or has caused an exception
if (string.IsNullOrWhiteSpace(logMessage))
{
// Note: state can be value or reference type as the messageFormatter delegate doesn't restrict the TState to class
// for example if state is int with value 6 the state.ToString() is called
logMessage = state?.ToString() ?? exception?.Message;
}
return(logMessage);
});
}
/// <summary>
/// Checks whether logging is enabled for the specified level.
/// </summary>
/// <param name="level">logging level</param>
/// <returns>true if logging for the level is enabled otherwise false</returns>
public bool IsEnabled(Epilog.Level level)
{
return(_logger.IsEnabled(MapEpiserverLogLevel(level)));
}
