Flume案例十：多路复用通道选择器(Multiplexing Channel Selector)

灰太狼 2022-10-10 12:52 231阅读 0赞

> 本文接上篇博客：[Flume介绍、安装、使用案例、自定义Source/Sink、监控][Flume_Source_Sink]  
> Flume 版本：1.9.0

## 1.多路复用通道选择器(Multiplexing Channel Selector) ##

> Flume多路复用：  
>   同一时刻，source只能传输给一个channel，source是通过 event header 来决定传输到哪一个 channel。  
>   即：Flume 多路复用，需配合自定义Interceptor来使用。比如：一个日志文件(多个系统的日志都在该文件中)，根据日志中某个字段值，比如type=1，是系统A日志，sink to hdfs；type=2，是系统B日志，sink to kafka，此时就可以使用Flume多路复用，通过event header 来决定传输到哪个Channel)  
>    
> 案例：  
>   Flume-1 监听 multiplex.log 日志文件；  
>   根据日志输入内容，配合 `Flume 自定义 Interceptor`，  
>   以`1`开头的，交给 Flume-2 处理；`2`开头的数据，交给 Flume-3 处理  
>    
> 选型：  
>  Flume-1：`taildir source` \+ `memory channel` \+ `avro sink` \+ `Multiplexing Channel Selector(多路复用渠道选择器)`  
>  Flume-2：`avro source` \+ `memory channel` \+ `logger sink`  
>  Flume-3：`avro source` \+ `memory channel` \+ `logger sink`  
>    
> 文档参考：  
>  **taildir source**：[http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html\#taildir-source][http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_taildir-source]  
>  **memory channel**：[http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html\#memory-channel][http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_memory-channel]  
>  **avro sink**：[http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html\#avro-sink][http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_avro-sink]  
>  **logger sink**：[http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html\#logger-sink][http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_logger-sink]  
>  **Multiplexing Channel Selector**：[http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html\#multiplexing-channel-selector][http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_multiplexing-channel-selector]

## 2.需求图示 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x6YjM0ODExMDE3NQ_size_16_color_FFFFFF_t_70]

## 3.自定义Interceptor ##

> 创建 Maven 工程，添加 Maven 依赖，自定义 Interceptor 即可

<dependency>
        <groupId>org.apache.flume</groupId>
        <artifactId>flume-ng-core</artifactId>
        <version>1.9.0</version>
    </dependency>

package com.flume.interceptor;
    
    import org.apache.flume.Context;
    import org.apache.flume.Event;
    import org.apache.flume.interceptor.Interceptor;
    
    import java.util.List;
    import java.util.Map;
    
    /** * 自定义Flume Interceptor拦截器 * @author : lzb * @date: 2021-06-22 11:15 */
    public class MyInterceptor implements Interceptor { 
    
        @Override
        public void initialize() { 
    
        }
    
        @Override
        public Event intercept(Event event) { 
            // 获取Event事件中的header信息
            Map<String, String> headers = event.getHeaders();
            // 获取Event事件中的body信息
            String body = new String(event.getBody());
            System.out.println("数据:" + body);
            // 根据body中的内容【如果1开头,则是系统A的日志;如果2开头,则是系统B的日志】这样来决定添加怎么样的头信息
            if ("1".equals(body.substring(0,1))) { 
                headers.put("type", "systemA");
                System.out.println("数据为1开头,进入header1-systemA");
            } else if ("2".equals(body.substring(0,1))) { 
                headers.put("type", "systemB");
                System.out.println("数据为2开头,进入header2-systemB");
            }
            return event;
        }
    
        @Override
        public List<Event> intercept(List<Event> events) { 
            // list参数,循环执行intercept()方法
            events.forEach(this::intercept);
            return events;
        }
    
        @Override
        public void close() { 
    
        }
    
        // 创建一个静态类
        public static class Builder implements Interceptor.Builder { 
    
            @Override
            public Interceptor build() { 
                return new MyInterceptor();
            }
    
            @Override
            public void configure(Context context) { 
    
            }
        }
    }

> 自定义Interceptor代码，来这里拿 [https://pan.baidu.com/s/1p4uToEcfLbJ0Nr-7ac1Y3Q ][https_pan.baidu.com_s_1p4uToEcfLbJ0Nr-7ac1Y3Q] （提取码：5fpy ）

## 4.flume配置 ##

### Ⅰ.Flume-1 ###

flume-taildir-avro-multiplexing.conf

# Name the components on this agent
    a1.sources = r1
    a1.sinks = k1 k2
    a1.channels = c1 c2
    
    # Flume Interceptors configure
    a1.sources.r1.interceptors = i1
    a1.sources.r1.interceptors.i1.type = com.flume.interceptor.MyInterceptor$Builder
    
    # Multiplexing Channel Selector configure(多路复用通道选择器配置)
    a1.sources.r1.selector.type = multiplexing
    a1.sources.r1.selector.header = type
    a1.sources.r1.selector.mapping.systemA = c1
    a1.sources.r1.selector.mapping.systemB = c2
    
    # Describe/configure the source
    a1.sources.r1.type = TAILDIR
    a1.sources.r1.positionFile = /opt/module/flume/position/taildir_multiplexing_position.json1
    a1.sources.r1.filegroups = f1
    a1.sources.r1.filegroups.f1 = /opt/module/testdir/multiplex.log
    
    # Describe the sink
    a1.sinks.k1.type = avro
    a1.sinks.k1.hostname = 192.168.204.202
    a1.sinks.k1.port = 41414
    
    a1.sinks.k2.type = avro
    a1.sinks.k2.hostname = 192.168.204.203
    a1.sinks.k2.port = 41414
    
    # Use a channel which buffers events in memory
    a1.channels.c1.type = memory
    a1.channels.c1.capacity = 1000
    a1.channels.c1.transactionCapacity = 100
    
    a1.channels.c2.type = memory
    a1.channels.c2.capacity = 1000
    a1.channels.c2.transactionCapacity = 100
    
    # Bind the source and sink to the channel
    a1.sources.r1.channels = c1 c2
    a1.sinks.k1.channel = c1
    a1.sinks.k2.channel = c2

### Ⅱ.Flume-2 ###

flume-avro-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 = avro
    a1.sources.r1.bind = 192.168.204.202
    a1.sources.r1.port = 41414
    
    # 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

### Ⅲ.Flume-3 ###

flume-avro-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 = avro
    a1.sources.r1.bind = 192.168.204.203
    a1.sources.r1.port = 41414
    
    # 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

## 5.启动命令 ##

> 注意：  
>   1.启动前，需要将自定义的 Interceptor 打包，并将jar包放到flume所在目录下的 lib 文件夹下；  
>   2.必须先启动 Flume-2 和 Flume-3，再启动 Flume-1。

# Flume-2 启动命令
    bin/flume-ng agent -c conf -n a1 -f job/multiplexing/flume-avro-logger.conf -Dflume.root.logger=INFO,console
    # Flume-3 启动命令
    bin/flume-ng agent -c conf -n a1 -f job/multiplexing/flume-avro-logger.conf -Dflume.root.logger=INFO,console
    # Flume-1 启动命令
    bin/flume-ng agent -c conf -n a1 -f job/multiplexing/flume-taildir-avro-multiplexing.conf

## 6.测试图示 ##

> Taildir Source 实时监听 `testdir/test.log` 和 `testdir/hive.log`
> 
> 1.  echo 方式追加数据至 `hive.log` 文件，模拟实时日志；会将数据写入hdfs 的 `/flume/aggregate` 目录下文件中
> 2.  echo 方式追加数据至 `test.log` 文件，模拟实时日志；也会将数据写入hdfs 的 `/flume/aggregate` 目录下文件中

**测试结果，如图所示：**  
![在这里插入图片描述][20210628170903258.gif]

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[Flume_Source_Sink]: https://blog.csdn.net/lzb348110175/article/details/118154430
[http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_taildir-source]: http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html#taildir-source
[http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_memory-channel]: http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html#memory-channel
[http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_avro-sink]: http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html#avro-sink
[http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_logger-sink]: http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html#logger-sink
[http_flume.apache.org_releases_content_1.9.0_FlumeUserGuide.html_multiplexing-channel-selector]: http://flume.apache.org/releases/content/1.9.0/FlumeUserGuide.html#multiplexing-channel-selector
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x6YjM0ODExMDE3NQ_size_16_color_FFFFFF_t_70]: /images/20221005/14c6b12d7fec45e495a64f8ee0971d13.png
[https_pan.baidu.com_s_1p4uToEcfLbJ0Nr-7ac1Y3Q]: https://pan.baidu.com/s/1p4uToEcfLbJ0Nr-7ac1Y3Q
[20210628170903258.gif]: /images/20221005/923ff3b59b4b4613884793a95544e0ce.png