使用 Autofac 的 RegisterGeneric 注入 NLog [英] Injecting NLog with Autofac's RegisterGeneric

问题描述

注意:更新了建议的改进，接近但仍然不完全！

Note: Updated with suggested improvements, closer but still not quite there!

类似于这个问题 - 使用 Autofac 传入 NLog 的声明类的类型 - 我试图将 NLog 实例注入到我的存储库类中.

Similar to this question - Passing in the type of the declaring class for NLog using Autofac - I am trying to inject NLog instances into my repository classes.

界面:

public interface ILogger<T>
    where T: class
{
    ...
}

实施:

public class NLogger<T> : ILogger<T>
    where T: class
{
    private readonly Logger _logger;

    public NLogger()
    {
        _logger = LogManager.GetLogger(typeof(T).FullName);
    }

    public void Debug(string message)
    {
        _logger.Debug(message);
    }

    ...
}

在 Autofac 注册为:

Registered with Autofac as:

builder.RegisterGeneric(typeof (NLogger<>)).As(typeof (ILogger<>));

使用断点，我看到 Autofac 正在为我的所有各种存储库创建一堆具有正确类型的 ILogger/NLogger，但结果日志显示调用站点为NLog.LoggerImpl.Write".

Using breakpoints, I see that Autofac is creating a bunch of ILogger/NLogger's with the correct types for all of my various repositories, but the resulting logs show up with callsite being "NLog.LoggerImpl.Write".

感谢您的帮助！

使用泛型的工作解决方案:

Working solution with generics:

public class NLogger<T> : ILogger<T>
    where T: class
{
    private readonly Logger _logger;

    public NLogger()
    {
        _logger = LogManager.GetLogger(typeof(T).FullName);
    }

    public void Debug(string message)
    {
        _logger.Log(typeof(T), new LogEventInfo(LogLevel.Debug, _logger.Name, message));
    }

推荐答案

Logger 包装器需要调用 .Log() 并传递附加信息以使 callsite 工作.例如:

Logger wrappers need to call .Log() and pass additional info for callsite to work. For example:

_logger.Log(typeof (NLogger<T>), new LogEventInfo(LogLevel.Debug, _logger.Name, null, format, args));

由于您仍然遇到问题，因此我是这样做的，而且我知道它的行为是正确的:

Since you're still having trouble, here's how I do it, and I know it's behaving correctly:

public interface ILog
{
    [StringFormatMethodAttribute("format")]
    void Debug(string format, params object[] args);
    [StringFormatMethodAttribute("format")]
    void Info(string format, params object[] args);
    [StringFormatMethodAttribute("format")]
    void Warn(string format, params object[] args);

    [StringFormatMethodAttribute("format")] 
    void Error(string format, params object[] args);
    void Error(Exception ex);

    [StringFormatMethodAttribute("format")]
    void Error(Exception ex, string format, params object[] args);

    [StringFormatMethodAttribute("format")]
    void Fatal(Exception ex, string format, params object[] args);
}

public class NLogLogger : ILog
{
    private readonly Logger _log;

    public NLogLogger(Type type)
    {
        _log = LogManager.GetLogger(type.FullName);
    }

    public void Debug(string format, params object[] args)
    {
        Log(LogLevel.Debug, format, args);
    }

    public void Info(string format, params object[] args)
    {
        Log(LogLevel.Info, format, args);
    }

    public void Warn(string format, params object[] args)
    {
        Log(LogLevel.Warn, format, args);
    }

    public void Error(string format, params object[] args)
    {
        Log(LogLevel.Error, format, args);
    }

    public void Error(Exception ex)
    {
        Log(LogLevel.Error, null, null, ex);
    }

    public void Error(Exception ex, string format, params object[] args)
    {
        Log(LogLevel.Error, format, args, ex);
    }

    public void Fatal(Exception ex, string format, params object[] args)
    {
        Log(LogLevel.Fatal, format, args, ex);
    }

    private void Log(LogLevel level, string format, object[] args)
    {
        _log.Log(typeof (NLogLogger), new LogEventInfo(level, _log.Name, null, format, args));
    }

    private void Log(LogLevel level, string format, object[] args, Exception ex)
    {
        _log.Log(typeof (NLogLogger), new LogEventInfo(level, _log.Name, null, format, args, ex));
    }
}

public class LoggingModule : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        builder
            .Register((c, p) => new NLogLogger(p.TypedAs<Type>()))
            .AsImplementedInterfaces();
    }

    protected override void AttachToComponentRegistration(IComponentRegistry componentRegistry, IComponentRegistration registration)
    {
        registration.Preparing +=
            (sender, args) =>
            {
                var forType = args.Component.Activator.LimitType;

                var logParameter = new ResolvedParameter(
                    (p, c) => p.ParameterType == typeof(ILog),
                    (p, c) => c.Resolve<ILog>(TypedParameter.From(forType)));

                args.Parameters = args.Parameters.Union(new[] { logParameter });
            };
    }
}

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