Log4j2 SyslogAppender not working

问题

I'm using Log4j version 2.1 (the latest stable version) and trying to use a Syslog appender to log to a syslog server. I'm using the configuration given at their official site (http://logging.apache.org/log4j/2.x/manual/appenders.html#SyslogAppender):

<Syslog name="RFC5424" format="RFC5424" host="localhost" port="514"
        protocol="UDP" appName="MyApp" includeMDC="true"
        facility="LOCAL0" enterpriseNumber="18060" newLine="true"
        messageId="Audit" id="App"/>

When I start my app and do a LogManager.getLogger(), I get an error (stack trace bellow), so, before I report an error to their bug tracker, am I doing something wrong?

014-11-17 18:26:23,640 ERROR Unable to invoke factory method in class class org.apache.logging.log4j.core.appender.SyslogAppender for element Syslog. java.lang.reflect.InvocationTargetException
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:606)
  at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:135)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:766)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:706)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:698)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:358)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:161)
  at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:359)
  at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:420)
  at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:138)
  at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:147)
  at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:41)
  at org.apache.logging.log4j.LogManager.getContext(LogManager.java:175)
  at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:426)
  at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:408)
  at Log.<clinit>(Log.java:7)
Caused by: java.lang.IllegalArgumentException: No structured id name was supplied
  at org.apache.logging.log4j.message.StructuredDataId.<init>(StructuredDataId.java:92)
  at org.apache.logging.log4j.core.layout.Rfc5424Layout.<init>(Rfc5424Layout.java:139)
  at org.apache.logging.log4j.core.layout.Rfc5424Layout.createLayout(Rfc5424Layout.java:657)
  at org.apache.logging.log4j.core.appender.SyslogAppender.createAppender(SyslogAppender.java:133)
... 19 more

回答1:

You need to include the mdcId attribute. e.g.:

<Syslog name="RFC5424" format="RFC5424" host="localhost" port="514"
        protocol="UDP" appName="MyApp" mdcId="mdc" includeMDC="true"
        facility="LOCAL0" enterpriseNumber="18060" newLine="true"
        messageId="Audit" id="App"/>

来源：https://stackoverflow.com/questions/26978520/log4j2-syslogappender-not-working

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java

logging

log4j

log4j2

syslog