springboot 日志框架 logback 自定义 appender 实现log日志数据通过websocket 推送到 前端进行滚动输出

实现效果展示

实现思路

因为考虑到服务会部署多个节点的情况下，页面前端要展示所有节点的日志，所以采用每个节点的日志发送到kafka，然后kafka的消费端，再通过websocket 发送到页面进行滚动显示
如果是单体应用，就可以再append里面直接把日志数据发送到websocket，不用发送到kafka进行归集

代码实现

appender代码

package org.lensyn.grpcserver.log;

import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.Layout;
import ch.qos.logback.core.UnsynchronizedAppenderBase;
import lombok.Getter;
import lombok.Setter;
import org.lensyn.grpcserver.common.util.DateTimeUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.SendResult;
import org.springframework.stereotype.Component;
import org.springframework.util.concurrent.ListenableFuture;

import java.net.InetAddress;
import java.net.UnknownHostException;

@Getter
@Setter
@Component
public class MyLogbackAppender extends UnsynchronizedAppenderBase<ILoggingEvent> {

    Layout<ILoggingEvent> layout;


    private InetAddress addr;


    private String GRPC_SERVER_NAME;

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;
    
    //自定义配置 
    String printString;



    
    @Override
    public void start(){
        //这里可以做些初始化判断 比如layout不能为null ,
        if(layout == null) {
            addWarn("Layout was not defined");
        }
        //或者写入数据库 或者redis时 初始化连接等等
         super.start();

        try {
            addr = InetAddress.getLocalHost();
            GRPC_SERVER_NAME = System.getenv("GRPC_SERVER_NAME");
        } catch (UnknownHostException e) {
            throw new RuntimeException(e);
        }
    }
    

    @Override
    public void stop()
    {
       //释放相关资源，如数据库连接，redis线程池等等
        System.out.println("logback-stop方法被调用");
        if(!isStarted()) {
            return;
        }
        super.stop();
    }
    
    @Override
    public void append(ILoggingEvent event) {
        if (event == null || !isStarted()){
            return;
        }
             // 此处自定义实现输出             
             // 获取输出值：event.getFormattedMessage()
             // System.out.print(event.getFormattedMessage());
             // 格式化输出        
        //System.out.print(printString + "：" + layout.doLayout(event));
        //ProducerService kafkaProducerService =  SpringContextUtil.getAppContext().getBean(ProducerServiceImpl.class);

        try {
            String pattern = "yyyy-MM-dd HH:mm:ss";
            String prfexString = "["+ GRPC_SERVER_NAME +"|"+ addr.getHostAddress()+"]" + DateTimeUtils.convertTimestamp2Date(event.getTimeStamp(),pattern) +"  "+ event.getLevel().levelStr +"  [ "+ event.getThreadName() + " ]  "+event.getLoggerName();
            if(event.getLoggerName().indexOf("kafka") != -1
                    || event.getLoggerName().indexOf("MyLogbackAppender") != -1){
                return;
            }
            //kafkaProducerService.sendMessage("test-topic",prfexString + " : " + event.getFormattedMessage());
            ListenableFuture<SendResult<String, String>> future = kafkaTemplate.send("test-topic",prfexString + " : " + event.getFormattedMessage());
            future.addCallback(success -> {
                //log.info("send to kafka sucess ! ");
            }, failure -> {
                //log.error("send to kafka Failure !  ression :{}", failure.getMessage());
            });
            //webSocketServer.sendMessage( prfexString + " : " + event.getFormattedMessage());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
          
    }
}

核心代码说明

继承UnsynchronizedAppenderBase<ILoggingEvent> 实现append方法

kafka消费端启动，和注册自定义的appender

package org.lensyn.grpcserver.kafka;

import ch.qos.logback.classic.LoggerContext;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.lensyn.grpcserver.log.MyLogbackAppender;
import org.lensyn.grpcserver.server.WebSocketServer;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.event.EventListener;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.kafka.config.KafkaListenerEndpointRegistry;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class KafkaConsumer {

    @Value("${spring.kafka.consumer.auto-startup}")
    private boolean autoStartup;

    @Autowired
    private KafkaListenerEndpointRegistry kafkaListenerEndpointRegistry;

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;
	
	@KafkaListener(id = "logConsumer", topics = "test-topic",groupId = "test-group",autoStartup = "false")
    public void onMassage(ConsumerRecord<Integer, String> record) {
		String topic = record.topic();
        String msg = record.value();
        WebSocketServer.SESSIONS.forEach( (s, session) -> {
            try {
                session.getBasicRemote().sendText(msg);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        });
        //LOGGER.info("msg-->{}",msg);
    }


    /**
    * 启动kafka消费端，通过配置项决定是否启动
    * 注册自定义实现的appender
    **/
    @EventListener(ApplicationReadyEvent.class)
    public void initialLogConsumer() {
        if(autoStartup){
            // 判断监听容器是否启动，未启动则将其启动
            if (!kafkaListenerEndpointRegistry.getListenerContainer("logConsumer").isRunning()) {
                kafkaListenerEndpointRegistry.getListenerContainer("logConsumer").start();
            }
            // 将其恢复
            kafkaListenerEndpointRegistry.getListenerContainer("logConsumer").resume();
        }

         
        //注册 自定义的日志Appender
        LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
        // 第二步：获取日志对象 （日志是有继承关系的，关闭上层，下层如果没有特殊说明也会关闭）
        ch.qos.logback.classic.Logger rootLogger = lc.getLogger("root");
        MyLogbackAppender myAppender = new MyLogbackAppender();
        myAppender.setContext(lc);
        // 自定义Appender设置name
        myAppender.setName("MyLogbackAppender");
        myAppender.start();
        myAppender.setKafkaTemplate(kafkaTemplate);
        rootLogger.addAppender(myAppender);


    }

}

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