Flume自定义Source

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。

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

[[e-mail] 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