spectre.console/examples/Cli/Logging/Infrastructure/LoggingEnricher.cs

using Serilog.Core;
using Serilog.Events;

namespace Logging
{
    internal class LoggingEnricher : ILogEventEnricher
    {
        private string _cachedLogFilePath;
        private LogEventProperty _cachedLogFilePathProperty;

        // this path and level will be set by the LogInterceptor.cs after parsing the settings
        public static string Path = string.Empty;

        public const string LogFilePathPropertyName = "LogFilePath";

        public void Enrich(LogEvent logEvent, ILogEventPropertyFactory propertyFactory)
        {
            // the settings might not have a path or we might not be within a command in which case
            // we won't have the setting so a default value for the log file will be required
            LogEventProperty logFilePathProperty;

            if (_cachedLogFilePathProperty != null && Path.Equals(_cachedLogFilePath))
            {
                // Path hasn't changed, so let's use the cached property
                logFilePathProperty = _cachedLogFilePathProperty;
            }
            else
            {
                // We've got a new path for the log. Let's create a new property
                // and cache it for future log events to use
                _cachedLogFilePath = Path;
                _cachedLogFilePathProperty = logFilePathProperty = propertyFactory.CreateProperty(LogFilePathPropertyName, Path);
            }

            logEvent.AddPropertyIfAbsent(logFilePathProperty);
        }
    }
}