四.Flume拦截器

Flume内置拦截器

官方文档 http://flume.apache.org/FlumeUserGuide.html
Timestamp Interceptor、Host Interceptor、Static Interceptor等等，可以直接拿来用，
以Timestamp Interceptor为例,在header中添加一个时间戳：
1）创建配置文件
vim timestramp_interceptor_demo.conf

# Name the components on this agent
a1.sources = r1
a1.sinks = k1
a1.channels = c1


# Describe/configure the source
a1.sources.r1.type = netcat
a1.sources.r1.bind = localhost
a1.sources.r1.port = 44444

# Describe interceptor
a1.sources.r1.interceptors = i1
a1.sources.r1.interceptors.i1.type = timestamp

# Describe the sink
a1.sinks.k1.type = logger


# Use a channel which buffers events in memory
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100


# Bind the source and sink to the channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

2)启动flume

flume-ng agent -n a1 -c conf/ -f jobs/timestramp_interceptor_demo.conf -Dflume.root.logger=INFO,console

3)另启一个终端测试

[v2admin@hadoop10 ~]$ nc localhost 44444
hello world
OK

4)在监听处观察

2020-12-26 17:31:33,919 (SinkRunner-PollingRunner-DefaultSinkProcessor) [INFO - org.apache.flume.sink.LoggerSink.process(LoggerSink.java:95)] Event: { headers:{timestamp=1608975093917} body: 68 65 6C 6C 6F 20 77 6F 72 6C 64                hello world }  // headers中可以看到时间戳

Flume自定义拦截器

认识Interceptor接口

public interface Interceptor {
  /**
  * 运行前的初始化，一般不需要实现
  */
  public void initialize();
  
  /**
  * 处理单个event
  */
  public Event intercept(Event event);

  /**
  * 批量处理event
  */
  public List intercept(List events);

  /**
  * 退出时做一些关闭工作
  */
  public void close();
  
  /**
  * 构建Interceptor对象，外部使用这个Builder来获取Interceptor对象。
  */
  public interface Builder extends Configurable {
    public Interceptor build();
  }
}

自定义一个拦截器

• 需求

有这样一server，产生这样的日志信息

qq.com 2020-11-10 11:10 XXXXXXXXXXXXXXXXXXXXXX
baidu.com 2020-10 11:11 XXXXXXXXXXXXXXXXXXXXXx
.....

flume采集数据，实现区分不同域名的内容，落在hdfs上
那么需要自定义一个拦截器

public class AddHeaderDomainIntecreptor implements Interceptor {
    @Override
    public void initialize() {
    }

    @Override
    public Event intercept(Event event) {
        Map headers = event.getHeaders();
        byte[] body = event.getBody();
        String strBody = null;
        try {
            strBody = new String(body,"utf-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        String[] s = strBody.split(" ");
        headers.put("domain",s[0]);
        return event;
    }

    @Override
    public List intercept(List list) {
        for (Event event : list) {
            intercept(event);
        }
        return list;
    }

    @Override
    public void close() {

    }

    public static class Builder implements Interceptor.Builder{

        @Override
        public Interceptor build() {
            return new AddHeaderDomainIntecreptor();
        }

        @Override
        public void configure(Context context) {

        }
    }
}