简介

Source是负责接收数据到Flume Agent的组件。Source组件可以处理各种类型、各种格式的日志数据，包括avro、thrift、exec、jms、spooling directory、netcat、sequence generator、syslog、http、legacy。官方提供的source类型已经很多，但是有时候并不能满足实际开发当中的需求，此时我们就需要根据实际需求自定义某些source。

官方也提供了自定义source的接口：
https://flume.apache.org/FlumeDeveloperGuide.html#source根据官方说明自定义MySource需要继承AbstractSource类并实现Configurable和PollableSource接口。

需求

使用flume接收数据，并给每条数据添加前缀，输出到控制台。前缀可从flume配置文件中配置。
Flume自定义Source - 图1

编写代码

创建个Maven工程

依赖

 <dependency>
        <groupId>org.apache.flume</groupId>
        <artifactId>flume-ng-core</artifactId>
        <version>1.7.0</version>
</dependency>

具体代码


import java.util.ArrayList;
import java.util.List;
import org.apache.flume.Context;
import org.apache.flume.Event;
import org.apache.flume.PollableSource;
import org.apache.flume.channel.ChannelProcessor;
import org.apache.flume.conf.Configurable;
import org.apache.flume.event.SimpleEvent;
import org.apache.flume.source.AbstractSource;
/*
 * 使用flume接收数据，并给每条数据添加前缀，输出到控制台。前缀可从flume配置文件中配置
 */
public class MySource extends AbstractSource implements Configurable, PollableSource {
    private String prefix;
    // 最核心方法，在process()中，创建Event，将event放入channel
    // Status{ READY, BACKOFF}
    // READY: source成功第封装了event，存入到channel，返回READY
    // BACKOFF： source无法封装了event，无法存入到channel，返回BACKOFF
    // process()方法会被Source所在的线程循环调用！
    @Override
    public Status process() {
        Status status = Status.READY;
        //封装event
        List<Event> datas = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            SimpleEvent e = new SimpleEvent();
            //向body中封装数据
            e.setBody((prefix + "hello" + i).getBytes());
            datas.add(e);
        }
        //将数据放入channel
        // 获取当前source对象对应的channelprocessor
        try {
            Thread.sleep(5000);
            ChannelProcessor cp = getChannelProcessor();
            cp.processEventBatch(datas);
        } catch (Exception e) {
            status = Status.BACKOFF;
            e.printStackTrace();
        }
        return status;
    }
    // 当source没有数据可封装时，会让source所在的线程先休息一会，休息的时间，由以下值*计数器系数
    @Override
    public long getBackOffSleepIncrement() {
        return 2000;
    }
    @Override
    public long getMaxBackOffSleepInterval() {
        return 5000;
    }
    // 从配置中来读取信息
    @Override
    public void configure(Context context) {
        //从配置文件中读取key为prefix的属性值，如果没有配置，提供默认值default:
        prefix = context.getString("prefix", "default:");
    }
}

Maven打包

Maven 先clean 再package

打成 Flume-0.0.1-SNAPSHOT.jar 之后放到apache-flume-1.7.0/lib目录下面

编写配置文件

# Name the components on this agent
a1.sources = r1
a1.sinks = k1
a1.channels = c1
# Describe/configure the source
a1.sources.r1.type = com.zjj.flume.custom.MySource
a1.sources.r1.delay = 1000
# 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 = 10000
a1.channels.c1.transactionCapacity = 1000
# Bind the source and sink to the channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

启动agent


[root@zjj101 job]# flume-ng agent -n a1  -c conf/  -f  "/root/soft/apache-flume-1.7.0/conf/job/demo1.conf"  -Dflume.root.logger=DEBUG,console

等待几秒控制台打印内容

20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 30       default:hello0 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 31       default:hello1 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 32       default:hello2 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 33       default:hello3 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 34       default:hello4 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 35       default:hello5 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 36       default:hello6 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 37       default:hello7 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 38       default:hello8 }
20/10/26 15:24:19 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 39       default:hello9 }
20/10/26 15:24:24 INFO sink.LoggerSink: Event: { headers:{} body: 64 65 66 61 75 6C 74 3A 68 65 6C 6C 6F 30       default:hello0 }

说明配置生效了..

代码

https://gitee.com/crow1/flume-my-source