NLog 自定义Target

http://nlog-project.org/2015/06/30/extending-nlog-is-easy.html

新建一个类库，命名规则为NLog.*.dll

定义一个类输出日志到RabbitMQ

    [Target("MQ")]
    public class MQTarget : TargetWithLayout
    {
        public MQTarget()
        {
        }
        public string Host { get; set; }

        public string UserName { get; set; }
        public string Password { get; set; }
        public string VirtualHost { get; set; }
        protected override void Write(LogEventInfo logEvent)
        {
            string message = this.Layout.Render(logEvent);
            SendMessageToMQ(Host,message);
        }
        private void SendMessageToMQ(string host,string message)
        {
            var factory = new ConnectionFactory() { HostName = Host,UserName= UserName, Password= Password, VirtualHost= VirtualHost};
            using (var connection = factory.CreateConnection())
            using (var channel = connection.CreateModel())
            {
                channel.QueueDeclare(queue: "apicenter",
                                     durable: false,
                                     exclusive: false,
                                     autoDelete: false,
                                     arguments: null);

                //string message = "Hello World!";
                var body = Encoding.UTF8.GetBytes(message);

                channel.BasicPublish(exchange: "",
                                     routingKey: "apicenter",
                                     basicProperties: null,
                                     body: body);
                Console.WriteLine(" [x] Sent {0}", message);
            }

        }
    }

nlog.config

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      autoReload="true"
      internalLogLevel="info"
      internalLogFile="Logs\internal-nlog.txt">

  <!-- enable asp.net core layout renderers -->
  <extensions>
    <add assembly="NLog.Web.AspNetCore"/>
    <add assembly="NLog.MQ"/>
  </extensions>

  <!-- the targets to write to -->
  <targets>
    <!-- write logs to file  -->
    <target xsi:type="File" name="allfile" fileName="Logs\nlog-all-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

    <!-- another file log, only own logs. Uses some ASP.NET core renderers -->
    <target xsi:type="File" name="info" fileName="Logs\nlog-info-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" />

    <target xsi:type="File" name="error" fileName="Logs\nlog-error-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" />

    <target xsi:type="MQ" name="mq" host="10.202.80.196" UserName="bm" Password="bm_p@ss" VirtualHost="NIST"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" />
  </targets>

  <!-- rules to map from logger name to target -->
  <rules>
    <!--All logs, including from Microsoft-->
    <logger name="*" minlevel="Info" writeTo="allfile" />

    <!--Skip non-critical Microsoft logs and so log only own logs-->
    <logger name="Microsoft.*" maxLevel="Info" final="true" />
    <!-- BlackHole without writeTo -->
    <logger name="*" level="Info" writeTo="info" />

    <logger name="*" level="Error" writeTo="error" />
    <logger name="*" level="Error" writeTo="mq" />
  </rules>
</nlog>

这里需要注意一点，部署到Linux中的话，需要把nlog.config中的\ 替换成 /

Filter

定义一个日志记录sql

namespace LogExtension
{
    public class NLogSql
    {
        private static NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();

        public static void Info(string message)
        {
            logger.Info(message);
        }
    }
}

调用方法

public static void LogSql(string txt)
        {
            NLogSql.Info(txt);
        }

配置target

    <target xsi:type="File" name="sql" fileName="Logs/sql/nlog-sql-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

    <target xsi:type="File" name="info" fileName="Logs/info/nlog-info-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

配置rule

    <logger name="*" level="Info" writeTo="info" />
    <logger name="LogExtension.NLogSql" level="Info" writeTo="sql" />

这样日志不仅会写到sql文件中，也会写到info中

定义filter

    <logger name="*" level="Info" writeTo="info" >
      <filters>
        <when condition="equals(logger,'LogExtension.NLogSql')" action="Ignore"/>
      </filters>
    </logger>

这样就在info中排除了sql的日志。

File

Configuration File

<target xsi:type="
            layout="${longdate}|${event-properties:item=EventId_Id}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

文件大小每超过1M就生成一个新的文件

<?xml version="1.0" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <targets>
        <!-- Log in a separate thread, possibly queuing up to
         messages. When the queue overflows, discard any
        extra messages-->

        <target name=" overflowAction="Discard">
            <target xsi:type="File" fileName="${basedir}/logs/${level}.txt" keepFileOpen="true" />
        </target>
    </targets>

    <rules>
        <logger name="*" minlevel="Debug" writeTo="file" />
    </rules>
</nlog>

支持异步写文件

wrapper

https://github.com/nlog/nlog/wiki/Configuration-file#default-wrappers

https://github.com/nlog/nlog/wiki/Configuration-file#asynchronous-processing-and-wrapper-targets