修改Flume Log4j Appender

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自定义Log4j Appender

要修改Flume Log4j Appender的实现，我们先了解一下Log4j Appender是如何自定义的。

自定义log4j appender需要继承log4j公共的基类：AppenderSkeleton

打印日志核心方法：abstract protected void append(LoggingEvent event);
初始化加载资源：public void activateOptions()，默认实现为空
释放资源：public void close()
是否需要按格式输出文本：public boolean requiresLayout()
正常情况下我们只需要覆盖append方法即可。然后就可以在log4j中使用了

Demo:

1. import org.apache.log4j.AppenderSkeleton;  2. import org.apache.log4j.spi.LoggingEvent;  3.   4. public class HelloAppender extends AppenderSkeleton {  5.   6.     private String account ;  7.       8.     @Override  9.     protected void append(LoggingEvent event) {  10.         System.out.println("Hello, " + account + " : "+ event.getMessage());  11.     }  12.   13.     @Override  14.     public void close() {  15.         // TODO Auto-generated method stub  16.   17.     }  18.   19.     @Override  20.     public boolean requiresLayout() {  21.         // TODO Auto-generated method stub  22.         return false;  23.     }  24.   25.     public String getAccount() {  26.         return account;  27.     }  28.   29.     public void setAccount(String account) {  30.         this.account = account;  31.     }  32. }

1. public static void main(String[] args) {  2.     Log log = LogFactory.getLog("helloLog") ;  3.     log.info("I am ready.") ;  4. }

log4j.properties 配置

log4j.logger.helloLog=INFO, hellolog4j.appender.hello=HelloAppenderlog4j.appender.hello.account=World

执行main函数，输出结果 Hello, World : I am ready.

修改FLume Log4j Appender

Event Header加入appname,hostname,logtype

由于hostname,logtype是固定不变的。所以直接写死在代码中。appname则用log4j.properties进行配置 – appname在log4j.properties中配置,添加：

#应用程序名log4j.appender.flume.Appname = 91pc

在Log4jAppender类中添加：

123456789

private String appname;public String getAppname() {  return appname;}public void setAppname(String appname) {  this.appname = appname;}

hostname,logtype在Log4jAppender类中添加

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//author:scytry {  hdrs.put("hostname", InetAddress.getLocalHost()+"");} catch (UnknownHostException e1) {      String msg = "Cant't get localhost IP";      LogLog.error(msg);      if (unsafeMode) {        return;      }      throw new FlumeException(msg + " Exception follows.", e1);}//author:scy Need to alarm(>Info)if(event.getLevel().toInt() > 20000){  hdrs.put("logtype", "alarm");}else{  hdrs.put("logtype", "log4j");}

Flume Log4j Appender添加log4j的异常详细信息

由于Flume Log4j Appender并没有将Log4j的错误异常栈详细信息封装到Event中，不利于我们的告警系统分析原因。 Log4jAppender.append()中添加如下：

12345678910111213141516171819202122232425

Event flumeEvent;Object message = event.getMessage();if (message instanceof GenericRecord) {..} else {  hdrs.put(Log4jAvroHeaders.MESSAGE_ENCODING.toString(), "UTF8");  //按照log4j.properties配置格式化日志  String msg = layout != null ? layout.format(event) : message.toString();          //author:edwardsbean  if(layout.ignoresThrowable()) {      String[] s = event.getThrowableStrRep();      if (s != null) {  int len = s.length;  for(int i = 0; i < len; i++) {      msg += s[i];      msg += Layout.LINE_SEP;  }    }  }    flumeEvent = EventBuilder.withBody(msg, Charset.forName("UTF8"), hdrs);}try {  rpcClient.append(flumeEvent);

日志接收端就可以接受到日志的详细信息：

 [x] Received '2013-12-26 10:38:08 user log detail [nd-PC2600/192.168.253.126] FATAL [com.xx.test.Main] java.lang.Exception: error detail  at com.xx.test.Main.main(Main.java:35)

Posted by EdwardsBean Dec 26th, 2013 Flume

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