Question

我有一个azure worker角色，我已将其配置为使用log4net Trace Appender写入WindowsAzure.Diagnostics。这是通过在辅助角色的RoleEntryPoint中进行以下调用来完成的。

using System;
using Microsoft.WindowsAzure.Diagnostics;
using log4net.Config;

namespace XXX
{
    public class WorkerRole : RoleEntryPoint
    {
        public override bool OnStart()
        {
            var config = DiagnosticMonitor.GetDefaultInitialConfiguration();

            config.Logs.ScheduledTransferLogLevelFilter = LogLevel.Warning;
            config.Logs.ScheduledTransferPeriod = TimeSpan.FromMinutes(5);

            config.WindowsEventLog.DataSources.Add("System!*");
            config.WindowsEventLog.DataSources.Add("Application!*");
            config.WindowsEventLog.ScheduledTransferLogLevelFilter = LogLevel.Error;
            config.WindowsEventLog.ScheduledTransferPeriod = TimeSpan.FromMinutes(5);

            DiagnosticMonitor.Start("Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString", config);

        XmlConfigurator.Configure();
        }
    }
}

App.config文件按以下方式配置：

<log4net>
    <appender name="TraceAppender" type="log4net.Appender.TraceAppender">
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%logger - %message" />
        </layout>
    </appender>
    <root>
        <level value="ALL" />
        <appender-ref ref="TraceAppender" />
    </root>
</log4net>

<system.diagnostics>
    <trace>
        <listeners>
            <add type="Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener, Microsoft.WindowsAzure.Diagnostics, Version=1.7.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" name="AzureDiagnostics">
                <filter type="" />
            </add>
        </listeners>
    </trace>
</system.diagnostics>

结果是所有消息（甚至错误）都以“详细”级别记录在表存储中。

如何解决这个问题？

Answer 1

有几篇博客文章涉及此问题:( here和here）

事实证明，log4net TraceAppender会转换所有日志消息 Trace.Write消息以及DiagnosticMonitorTraceListener将所有Trace.Write消息转换为详细信息。

我的答案是使用Pete McEvoy的解决方案并以下列方式扩展TraceAppender：

using System.Diagnostics;
using log4net.Appender;
using log4net.Core;
namespace XXX.Logging
{
    public class AzureTraceAppender : TraceAppender
    {
        protected override void Append(LoggingEvent loggingEvent)
        {
            var level = loggingEvent.Level;
            var message = RenderLoggingEvent(loggingEvent);

            if (level >= Level.Error)
              Trace.TraceError(message);
            else if (level >= Level.Warn)
              Trace.TraceWarning(message);
            else if (level >= Level.Info)
              Trace.TraceInformation(message);
            else
              Trace.WriteLine(message);
            if (ImmediateFlush)
              Trace.Flush();
        }
    }
}

然后在我的App.config中实现了这个扩展：

<log4net>
    <appender name="AzureTraceAppender" type="XXX.Logging.AzureTraceAppender">
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%logger - %message" />
        </layout>
    </appender>
    <root>
        <level value="ALL" />
        <appender-ref ref="AzureTraceAppender" />
    </root>
</log4net>

log4net traceappender仅记录级别为“详细”的消息。使用Windows Azure DiagnosticsMonitor时

1 个答案: