64 lines
1.8 KiB
Markdown
64 lines
1.8 KiB
Markdown
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# 消息队列MQ
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## 初识MQ
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### **同步调用**
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<img src="https://pic.bitday.top/i/2025/05/27/so4pss-0.png" alt="image-20250527173401081" style="zoom: 67%;" />
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同步调用有3个问题：
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- **拓展性差**，每次有新的需求，现有支付逻辑都要跟着变化，代码经常变动
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- **性能下降**，每次远程调用，调用者都是阻塞等待状态。最终整个业务的响应时长就是每次远程调用的执行时长之和
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- **级联失败**，当交易服务、通知服务出现故障时，整个事务都会回滚，交易失败。
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### 异步调用
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### 技术选型
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## RabbitMQ
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### 部署
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```yml
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mq:
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image: rabbitmq:3.8-management
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container_name: mq
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restart: unless-stopped
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hostname: mq
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environment:
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RABBITMQ_DEFAULT_USER: admin
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RABBITMQ_DEFAULT_PASS: "admin"
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RABBITMQ_PLUGINS_DIR: "/plugins:/custom-plugins"
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ports:
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- "15672:15672"
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- "5672:5672"
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volumes:
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- ./mq-plugins:/custom-plugins
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networks:
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- hmall-net
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```
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http://localhost:15672/ 访问控制台
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### 架构图
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- **`publisher`**：生产者，发送消息的一方
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- **`consumer`**：消费者，消费消息的一方
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- **`queue`**：队列，存储消息。生产者投递的消息会暂存在消息队列中，等待消费者处理
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- **`exchange`**：交换机，负责消息路由。生产者发送的消息由交换机决定投递到哪个队列。**不存储**
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- **`virtual host`**：虚拟主机，起到数据隔离的作用。每个虚拟主机相互独立，有各自的exchange、queue
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