springboot 启动时校验rabbitmq是否连接成功

1.业务场景

当springboot项目启动时，rabbitmq中间件可能还没有启动成功，这时候springboot项目会直接挂掉，业务需要等待rabbitmq启动成功之后再进行连接redis。

2.项目结构配置

pom文件使用redisson依赖，配置如下：

<dependency>
 <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
    <version>2.3.12.RELEASE</version>
</dependency>

rabbitmq连接配置：

package com.hero.rabbitmq.config;

import org.apache.commons.lang.StringUtils;
import org.springframework.amqp.rabbit.connection.CachingConnectionFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;

@Configuration
@DependsOn(value = "springContextHolder")
@Conditional(RabbitmqCondition.class)
public class RabbitmqConfig {
    

    @Bean
    public CachingConnectionFactory connectionFactory(
          @Value("${myConfig.rabbitmq.host}") String host,
          @Value("${myConfig.rabbitmq.port}") int port,
            @Value("${myConfig.rabbitmq.username}") String username,
            @Value("${myConfig.rabbitmq.password}") String password,
            @Value("${myConfig.rabbitmq.virtual-host}") String virtualHost,
            @Value("${myConfig.rabbitmq.publisher-returns}") Boolean publisherReturns
    ) {


        if (StringUtils.isNotEmpty(host)) {
            CachingConnectionFactory connectionFactory = new CachingConnectionFactory();
            connectionFactory.setHost(host);
            connectionFactory.setPort(port);
            connectionFactory.setUsername(username);
            connectionFactory.setPassword(password);
            connectionFactory.setVirtualHost(virtualHost);
            connectionFactory.setPublisherReturns(publisherReturns);

            return connectionFactory;
        } else {
            return null;
        }
    }

}

3.增加项目启动时rabbitmq校验

校验逻辑：rabbitmq连接失败则一直重试直到连接成功为止，代码如下：

3.1. 获取 Spring 应用上下文的抽象类

参考文章：springboot 启动时校验redis是否连接成功 中的抽象类部分AbstractValidateItem

3.2 具体校验实现类

package com.hero.validate;

import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.DependsOn;
import org.springframework.stereotype.Component;

@Slf4j
@Component
@DependsOn(value = "springContextHolder")
public class ValidateMessageBroker extends AbstractValidateItem {
    
    private String host;
    @Value("${myConfig.rabbitmq.port}")
    private Integer port;
    @Value("${myConfig.rabbitmq.username}")
    private String userName;
    @Value("${myConfig.rabbitmq.password}")
    private String password;
    

    @Override
    public void validate() {
        log.info(">>> ValidateMessageBroker ,validate ");
        rabbitMqValid();
    }

    public void rabbitMqValid() {
        for (int i = 1; i <= 1000000; i++) {
            try {
                Thread.sleep(backoff(i));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            try {
                Connection connection = getRabbitmqConnection();
                if (connection != null) {
                    log.info(" check connect rabbitmq ok");
                    return;
                } else {
                    log.warn("  retry connect ysp-kube qry rabbitmqaddr {} fail", i);
                }

            } catch (Exception e) {
                if (i == 1) {
                    e.printStackTrace();
                }
                log.warn("  retry connect rabbitmq {} fail", i);
                if (i == 1000000) {
                    log.error(" nms will be restarted for retry connect rabbitmq {} fail ,error:{}", i, e);
                    getContext().close();
                }
            } finally {

            }
        }
    }

    public Connection getRabbitmqConnection() throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost(host);
        factory.setPort(port);
        factory.setUsername(userName);
        factory.setPassword(password);
        factory.setVirtualHost("/");
        factory.setExceptionHandler(new RabbitMQExceptionHandler());
        Connection connection = factory.newConnection();
        return connection;

    }


    public static int backoff(int n) {
        if (n > 5) {
            n = 5;
        }
        return 2000 * n;
    }


}

这样，当srpingboot项目启动时会校验rabbitmq是否可以成功连接，如果失败则会一直重试直到连接成功。