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ILogger的定制实现

asp.net-core-2.1 .net-core asp.net-core

0

monty · 技术社区 · 7 年前

在我的项目中,我经常在日志消息中添加前缀。

      logger.LogDebug(prefix + " some message");

我认为这是实现自定义记录器的一个好方法,在这里我设置前缀,记录器每次记录某些内容时都会附加前缀。

    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)

方法添加前缀(它是自定义记录器类的成员)。

我的全部代码是:

      public class CustomLogger : ILogger
      {

        private readonly ILogger _logger;
        private string _logPrefix;

        public CustomLogger(ILogger logger)
        {
          _logger = logger ?? throw new ArgumentNullException(nameof(logger));
        _logPrefix = null;
        }

        public ILogger SetLogPrefix(string logPrefix)
        {
          _logPrefix = logPrefix;
          return this;
        }

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

        public bool IsEnabled(LogLevel logLevel)
        {
          return _logger.IsEnabled(logLevel);
        }

        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
        {
          _logger.Log(logLevel, eventId, state, exception, formatter);
        }

      }

3 回复 | 直到 7 年前

1

7

Hung Quach 7 年前

就我个人而言,我认为这不是一个好办法,“前缀”会被大量重复。你为什么不使用 Log Scopes

public IActionResult GetById(string id)
{
    TodoItem item;
    using (_logger.BeginScope("Message attached to logs created in the using block"))
    {
        _logger.LogInformation(LoggingEvents.GetItem, "Getting item {ID}", id);
        item = _todoRepository.Find(id);
        if (item == null)
        {
            _logger.LogWarning(LoggingEvents.GetItemNotFound, "GetById({ID}) NOT FOUND", id);
            return NotFound();
        }
    }
    return new ObjectResult(item);
}

输出

info: TodoApi.Controllers.TodoController[1002]
      => RequestId:0HKV9C49II9CK RequestPath:/api/todo/0 => TodoApi.Controllers.TodoController.GetById (TodoApi) => Message attached to logs created in the using block
      Getting item 0
warn: TodoApi.Controllers.TodoController[4000]
      => RequestId:0HKV9C49II9CK RequestPath:/api/todo/0 => TodoApi.Controllers.TodoController.GetById (TodoApi) => Message attached to logs created in the using block
      GetById(0) NOT FOUND

目前,您无法更改日志模板,这是Asp.net内核中内置基本日志的限制。对于更强大的一个,你可以尝试 Serilog ,继续使用 ILogger program.cs 班

你也应该看看这个 Benefits of Structured Logging vs basic logging

2

10

Håkon K. Olafsen 7 年前

我认为您不应该在自定义记录器中调用_记录器。

这将是运行时的循环调用,结果将是“prefix:prefix:prefix:prefix:prefix:prefix:prefix:…”

简单地说,您可以创建一个简单的日志记录器并实现一个日志写入程序,如控制台、数据库写入程序、log4net等等。。。

现在,首先,您应该更改自定义记录器,如下所示:

    public class CustomLogger : ILogger
    {
        private readonly string CategoryName;
        private readonly string _logPrefix;

        public CustomLogger(string categoryName, string logPrefix)
        {
            CategoryName = categoryName;
            _logPrefix = logPrefix;
        }

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

        public bool IsEnabled(LogLevel logLevel)
        {
            return true;
        }

        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
        {
            string message = _logPrefix;
            if (formatter != null)
            {
                message += formatter(state, exception);
            }
            // Implement log writter as you want. I am using Console
            Console.WriteLine($"{logLevel.ToString()} - {eventId.Id} - {CategoryName} - {message}");
        }

        private class NoopDisposable : IDisposable
        {
            public void Dispose()
            {
            }
        }
    }

第二步,创建记录器提供程序:

     public class LoggerProvider : ILoggerProvider
        {     
            public ILogger CreateLogger(string categoryName)
            {                
                return new CustomLogger(categoryName, "This is prefix: ");
            }

            public void Dispose()
            {
            }
        }

    loggerFactory.AddProvider(new MicroserviceLoggerProvider());

3

Edward 7 年前

prefix

    public static class LogExtensions
    {
        public static void PrefixLogDebug(this ILogger logger, string message, string prefix = "Edward", params object[] args)
        {
            logger.LogDebug($"{prefix} {message}");
        }
    }

用途:

        _log.PrefixLogDebug("Log From Prefix extension");
        _log.PrefixLogDebug("Log From Prefix extension", "New Prefix");