springboot+logback+kafka日志发送到Kafka

下载安装Kafka

下载安装zookeeper参考：https://blog.csdn.net/she_lock/article/details/80435176
下载安装Kafka参考：https://blog.csdn.net/qq_29116427/article/details/79949402

本文假设你已经有一个配置好logback的spring boot项目

maven

<dependency>
    <groupId>org.springframework.kafka</groupId>
    <artifactId>spring-kafka</artifactId>
</dependency>

logback.xml文件添加Kafka配置

<appender name="kafkaAppender" 
class="com.zoe.virtual.card.manage.infrastructure.kafkalog.KafkaAppender">
    </appender>
    
<root level="debug">
        <appender-ref ref="kafkaAppender" />
    </root>

添加KafkaAppender.Class

import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.ConsoleAppender;
import com.zoe.virtual.card.infrastructure.context.bean.SpringContextHolder;
import org.springframework.kafka.core.KafkaTemplate;

public class KafkaAppender extends ConsoleAppender<ILoggingEvent> {

    private KafkaTemplate kafkaTemplate;

    @Override
    public void start() {
        super.start();
        Map<String, Object> props = new HashMap();
        props.put("bootstrap.servers", "ip:端口号");
        props.put("retries", 0);
        props.put("batch.size", 16384);
        props.put("buffer.memory", 33554432);
        props.put("key.serializer", StringSerializer.class);
        props.put("value.serializer", StringSerializer.class);
        kafkaTemplate = new KafkaTemplate(DefaultKafkaProducerFactory(props));
        kafkaTemplate.send("test", "连接到Kafka。。。。。。。");// 先连接一遍，如果去掉可能报   Failed to update metadata after 60000 ms
    }


    @Override
    protected void append(ILoggingEvent eventObject) {
        kafkaTemplate.send("test", eventObject.getFormattedMessage());
    }

}

yml配置注意(踩到的坑，没有遇到的可以忽略)！！！

kafaka整合springboot 错误：Failed to update metadata after 60000 ms
如果你用spring boot直接连接Kafka不报错的话，而加上logback报错的话可能是下原因。

如果你要换成yml配置方式，那你需要注意以下几点
1、KafkaAppender 加载比spring容器启动还快，自己写个@Configuration的类去加载配置文件吧！在KafkaAppender中写是 获取不到值的。(除非你手动获取yml文件)
2、如果你换成了@Configuration文件配置，那你需要在一个@Controller注释的类中注入KafkaTemplate类。
3、在KafkaAppender类中的append()方法中不能直接去连接Kafka(kafkaTemplate.send()方法)，必须要在@Configuration 中先连接一次(在执行append()方法前需要先连接一遍)

我也不知道为啥少一个就报错，连接不上，这里把问题记一下，坑！

我的配置@Configuration类的配置

import org.apache.kafka.common.serialization.StringSerializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;

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

@Configuration
@EnableKafka//配合@Configuration注解一起用，会激活Kafka的基于注解驱动的消息消费功能
public class KafkaConfig {

    @Value("${spring.kafka.bootstrap-servers}")
    private String servers;
    @Value("${spring.kafka.producer.retries}")
    private int retries;
    @Value("${spring.kafka.producer.batch-size}")
    private int batchSize;
    @Value("${spring.kafka.producer.buffer-memory}")
    private int bufferMemory;


    public Map<String, Object> producerConfigs() {
        Map<String, Object> props = new HashMap();
        props.put("bootstrap.servers", this.servers);
        props.put("retries", this.retries);
        props.put("batch.size", this.batchSize);
        props.put("buffer.memory", this.bufferMemory);
        props.put("key.serializer", StringSerializer.class);
        props.put("value.serializer", StringSerializer.class);
        return props;
    }

    public ProducerFactory<String, String> producerFactory() {
        return new DefaultKafkaProducerFactory(this.producerConfigs());
    }

    @Bean
    public KafkaTemplate<String, String> kafkaTemplate() {
        KafkaTemplate kafkaTemplate = new KafkaTemplate(this.producerFactory());
        kafkaTemplate.send("test", "连接到Kafka。。。。。。。");
        return kafkaTemplate;
    }

}

我的KafkaAppender

import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.ConsoleAppender;
import com.zoe.virtual.card.infrastructure.context.bean.SpringContextHolder;
import org.springframework.kafka.core.KafkaTemplate;

public class KafkaAppender extends ConsoleAppender<ILoggingEvent> {

    private KafkaTemplate<String, String> kafkaTemplate;

    @Override
    public void start() {
        super.start();
    }


    @Override
    protected void append(ILoggingEvent eventObject) {
        if (kafkaTemplate != null){
            kafkaTemplate.send("test", eventObject.getFormattedMessage());
        }else if (SpringContextHolder.applicationContext != null){// 配置加载完毕发送消息到Kafka SpringContextHolder获取spring上下文（这个代码就不贴了）
            kafkaTemplate = (KafkaTemplate<String, String>)SpringContextHolder.getBean("kafkaTemplate");
            kafkaTemplate.send("test", eventObject.getFormattedMessage());
        }
    }

}

在Controller中添加KafkaTemplate

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping(value = "kafka")
public class KafkaConreoller {

    @Autowired
    private KafkaTemplate template;

}

后言

其实还有个思路，以后可能会完善。
使用@PostConstruct注解，启动前去连接Kafka，当这个配置加载完毕的时候，再去KafkaAppender的append()方法中发送消息到Kafka，就不要那么麻烦了