oqtane.framework/Oqtane.Server/Infrastructure/Logging/FileLogger.cs

using System;
using System.IO;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Logging;

namespace Oqtane.Infrastructure
{
    public class FileLogger : ILogger
    {
        protected readonly FileLoggerProvider _FileLoggerProvider;
        private readonly IWebHostEnvironment _environment;
        private readonly IConfigManager _configManager;

        public FileLogger(FileLoggerProvider FileLoggerProvider, IWebHostEnvironment environment,IConfigManager configManager)
        {
            _FileLoggerProvider = FileLoggerProvider;
            _environment = environment;
            _configManager = configManager;
        }

        public IDisposable BeginScope<TState>(TState state)
        {
            return null;
        }

        public bool IsEnabled(LogLevel logLevel)
        {
            return logLevel != LogLevel.None;
        }

        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
        {
            if (_configManager.GetSetting("Logging:FileLogger:LogLevel:Default", "") == "")
            {
                _configManager.AddOrUpdateSetting("Logging:FileLogger:LogLevel:Default", "Error", true);
                if (logLevel < LogLevel.Error)
                {
                    return;
                }
            }

            if (!IsEnabled(logLevel))
            {
                return;
            }

            string folder = Path.Combine(_environment.ContentRootPath, "Content", "Log");

            // ensure directory exists
            if (!Directory.Exists(folder))
            {
                Directory.CreateDirectory(folder);
            }

            var filepath = Path.Combine(folder, "error.log");

            var logentry = string.Format("{0} [{1}] {2} {3}", "[" + DateTimeOffset.UtcNow.ToString("yyyy-MM-dd HH:mm:ss+00:00") + "]", logLevel.ToString(), formatter(state, exception), exception != null ? exception.StackTrace : "");

            try
            {
                using (var streamWriter = new StreamWriter(filepath, true))
                {
                    streamWriter.WriteLine(logentry);
                }
            }
            catch
            {
                // error occurred
            }
        }
    }
}