Flume快速入门系列(8) | 如何自定义Source

不温卜火

发布于 2020-10-28 16:04:22

8500

发布于 2020-10-28 16:04:22

文章被收录于专栏：不温卜火

这篇文章我们讲解的是如何自定义Source。

1. Source的简单介绍

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。实现相应方法：

getBackOffSleepIncrement()//暂不用
getMaxBackOffSleepInterval()//暂不用
configure(Context context)//初始化context（读取配置文件内容）

process()//获取数据封装成event并写入channel，这个方法将被循环调用。
使用场景：读取MySQL数据或者其他文件系统。

2. 需求/分析

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。

3. 编码

3.1 导入pom依赖

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
    
    <dependencies>
        <dependency>
            <groupId>org.apache.flume</groupId>
            <artifactId>flume-ng-core</artifactId>
            <version>1.7.0</version>
        </dependency>

    </dependencies>

3.2 编写代码

package com.buwenbuhuo;


import org.apache.flume.Context;
import org.apache.flume.EventDeliveryException;
import org.apache.flume.PollableSource;
import org.apache.flume.conf.Configurable;
import org.apache.flume.event.SimpleEvent;
import org.apache.flume.source.AbstractSource;

import java.util.HashMap;
import java.util.Map;

/**
 * @author 卜温不火
 * @create 2020-05-04 16:00
 * com.buwenbuhuo - the name of the target package where the new class or interface will be created.
 * flumeplugins0504 - the name of the current project.
 */

public class MySource extends AbstractSource implements Configurable, PollableSource {

    //定义需要从配置中读取的字段

    //两条数据之间的间隔
    private long delay;
    private String field;


    public Status process() throws EventDeliveryException {
        try {
            Map<String, String> header = new HashMap<>();
            SimpleEvent event = new SimpleEvent();
            //拿到数据
            for (int i = 0; i < 5; i++) {
                event.setHeaders(header);
                event.setBody((field + i).getBytes());
                getChannelProcessor().processEvent(event);
                Thread.sleep(delay);
            }
        } catch (Exception e) {
            return Status.BACKOFF;
        }
        return Status.READY;
    }

    public long getBackOffSleepIncrement() {
        return 0;
    }

    public long getMaxBackOffSleepInterval() {
        return 0;
    }

    public void configure(Context context) {
        delay = context.getLong("delay", 2000l);
        field = context.getString("field", "buwenbuhuo");
    }
}

4. 测试

1 打包上传

将写好的代码打包，并放到flume的lib目录（/opt/module/flume/lib）下。

2. 配置文件

[bigdata@hadoop002 job]$ cp flume-netcat-logger.conf flume-mysource-logger.conf
[bigdata@hadoop002 job]$ vim flume-mysource-logger.conf 


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

# Describe/configure the source
a1.sources.r1.type = com.buwenbuhuo.MySource
a1.sources.r1.delay = 2000
a1.sources.r1.field = buwenbuhuo

# 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

3. 开启任务

[bigdata@hadoop002 flume]$ [bigdata@hadoop002 flume]$ bin/flume-ng agent -c conf/ -f job/flume-mysource-logger.conf  -n a1 -Dflume.root.logger=INFO,console