Serilog 范围的临时日志记录抑制

Question

我需要能够暂时禁用某些范围的日志记录。在我的例子中，有一个后台任务定期尝试为系统中每个可用的 COM 端口实例化一些设备 API 并查看它是否失败。 API 会在发生故障时写入大量信息（异常、内部组件 Dispose 调用等）。结果，日志每秒都充斥着此类不成功的尝试错误。

我提出了使用 LogContext.PushProperty 来识别被抑制的日志事件的解决方案。但是，以下代码不会记录任何内容：

internal static class Program
{
    public static void Main(String[] args)
    {
        void StartListeningSomething()
        {
            Task.Factory.StartNew(() =>
            {
                while (true)
                {
                    Log.Information("Listening");
                    Thread.Sleep(500);
                }
            }, TaskCreationOptions.LongRunning);
        }

        Log.Logger = new LoggerConfiguration()
            .Enrich.WithThreadId()
            .Filter.ByExcluding(logEvent => logEvent.Properties.ContainsKey("SuppressLogging"))
            .Enrich.FromLogContext()
            .WriteTo.Console(new JsonFormatter())
            .CreateLogger();

        using (LogContext.PushProperty("SuppressLogging", true))
        {
            StartListeningSomething();
            Console.ReadKey(); // Will ignore background thread log messages until key enter
        }

        // We want to start logging events after exiting using block
        // But they won't be logged for listener thread at all

        Console.ReadKey();
    }
}

侦听器任务中的所有日志事件都将被 "SupressLogging" 属性丰富，即使在从范围中弹出后也是如此。

Answer 1

我找到的唯一解决方法（除了整个 API 中繁琐的自定义传递 ILogger）包括以下步骤：

为"SupressLogging"分配一些唯一值属性
将此值添加到内部静态存储
退出范围时，从存储中删除此值（无效）
在记录器配置的 Filter 部分，检查是否附加了属性以及它的值是否有效（包含在存储中）。

以下代码使用自定义 IDisposable 令牌使其看起来像往常一样 PushProperty

internal static class Program
{
    public static void Main(String[] args)
    {
        void StartListeningSomething()
        {
            Task.Factory.StartNew(() =>
            {
                while (true)
                {
                    Log.Information("Listening");
                    Thread.Sleep(500);
                }
            }, TaskCreationOptions.LongRunning);
        }

        Log.Logger = new LoggerConfiguration()
            .Enrich.WithThreadId()
            .Filter.ByExcluding(logEvent => logEvent.IsSuppressed()) // Check if log event marked with supression property
            .Enrich.FromLogContext()
            .WriteTo.Console(new JsonFormatter())
            .CreateLogger();

        using (SerilogExtensions.SuppressLogging())
        {
            StartListeningSomething();
            Console.ReadKey(); // Will ignore background thread log messages until some key is entered
        }

        // Will start logging events after exiting the using block

        Console.ReadKey();
    }
}

而实际的 SerilogExtensions：

/// <summary>
///     Provides helper extensions to Serilog logging.
/// </summary>
public static class SerilogExtensions
{
    private const           String        SuppressLoggingProperty = "SuppressLogging";
    private static readonly HashSet<Guid> ActiveSuppressions      = new HashSet<Guid>();

    /// <summary>
    ///     Get disposable token to supress logging for context.
    /// </summary>
    /// <remarks>
    ///     Pushes "SuppressLogging" property with unique value to SerilogContext.
    ///     When disposed, disposes Serilog property push token and invalidates stored value so new log messages are no longer
    ///     supressed.
    /// </remarks>
    public static IDisposable SuppressLogging()
    {
        return new SuppressLoggingDisposableToken();
    }

    /// <summary>
    ///     Determines whether the given log event suppressed.
    /// </summary>
    /// <remarks>
    ///     Also removes "SuppressLogging" property if present.
    /// </remarks>
    public static Boolean IsSuppressed(this LogEvent logEvent)
    {
        Boolean containsProperty = logEvent.Properties.TryGetValue(SuppressLoggingProperty, out var val);
        if (!containsProperty)
            return false;

        logEvent.RemovePropertyIfPresent(SuppressLoggingProperty); //No need for that in logs

        if (val is ScalarValue scalar && scalar.Value is Guid id)
            return ActiveSuppressions.Contains(id);

        return false;
    }

    /// <summary>
    ///     Disposable wrapper around logging supression property push/pop and value generation/invalidation.
    /// </summary>
    private class SuppressLoggingDisposableToken : IDisposable
    {
        private readonly IDisposable _pushPropertyDisposable;
        private readonly Guid        _guid;

        public SuppressLoggingDisposableToken()
        {
            _guid                   = Guid.NewGuid();
            _pushPropertyDisposable = LogContext.PushProperty(SuppressLoggingProperty, _guid);

            ActiveSuppressions.Add(_guid);
        }

        public void Dispose()
        {
            ActiveSuppressions.Remove(_guid);
            _pushPropertyDisposable.Dispose();
        }
    }
}

可以在 github 上找到完整的示例项目。

我想在这里留下这个自我回答的问题，也想问问更多有经验的 Serilog 用户他们对这个问题的看法。可能有一些我没有找到的记录抑制的常用方法？

Answer 2

我想添加到 ArXen42 答案中。

建议的用于跟踪 activesuppression 键的哈希集不是线程安全的，并且在使用多线程时会产生问题。

一种解决方案是使用 ConcurrentDictionary<T,T2> 而不是 HashSet<T> 或下面所述的解决方案，而不跟踪 GUID 来抑制日志。

///     Provides helper extensions to Serilog logging.
/// </summary>
public static class SerilogExtensions
{
    private const string SuppressLoggingProperty
        = "SuppressLogging";

    /// <summary>
    ///     Get disposable token to supress logging for context.
    /// </summary>
    public static IDisposable SuppressLogging()
    {
        return LogContext.PushProperty(SuppressLoggingProperty, true);
    }

    /// <summary>
    ///     Determines whether the given log event suppressed.
    /// </summary>
    /// <remarks>
    ///     Also removes "SuppressLogging" property if present.
    /// </remarks>
    public static bool IsSuppressed(this LogEvent logEvent)
    {
        var containsProperty = logEvent.Properties
            .TryGetValue(SuppressLoggingProperty, out var val);

        if (!containsProperty)
            return false;

        // remove suppression property from logs
        logEvent.RemovePropertyIfPresent(SuppressLoggingProperty);

        if (val is ScalarValue scalar && scalar.Value is bool isSuppressed)
            return isSuppressed;

        return false;
    }
}

Serilog 范围的临时日志记录抑制

Temporary logging suppression for a scope in Serilog

c#

logging

serilog