修改Flume Log4j Appender
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
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打印日志核心方法：abstract protected void append(LoggingEvent event);
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初始化加载资源：public void activateOptions()，默认实现为空
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释放资源：public void close()
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是否需要按格式输出文本：public boolean requiresLayout()
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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
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log4j.logger.helloLog=INFO, hello
log4j.appender.hello=HelloAppender
log4j.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：
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#应用程序名
log4j.appender.flume.Appname = 91pc
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在Log4jAppender类中添加：
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private String appname;
public String getAppname() {
return appname;
}
public void setAppname(String appname) {
this.appname = appname;
}
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hostname,logtype在Log4jAppender类中添加
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//author:scy
try {
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：
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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;
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：
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Received '2013-12-26 10:38:08 user log detail
FATAL 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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