Go项目实战—RabbitMq篇

技术栈

• gin
• gorm
• rabbitmq

---

数据库表结构：

CREATE TABLE `article` (
  `id` int NOT NULL AUTO_INCREMENT,
  `article_name` varchar(64) COLLATE utf8mb4_unicode_ci NOT NULL,
  `content` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `user_id` int NOT NULL,
  `desc` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL,
  `status` smallint NOT NULL COMMENT '状态',
  `created_at` datetime NOT NULL COMMENT '创建时间',
  `updated_at` datetime NOT NULL COMMENT '更新时间',
  `deleted_at` datetime DEFAULT NULL COMMENT '删除时间',
  PRIMARY KEY (`id`),
  KEY `idx_article_deleted_at` (`deleted_at`),
  KEY `idx_article_user_id` (`user_id`),
  KEY `idx_article_status` (`status`),
  KEY `idx_content` (`article_name`,`content`)
) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

---

向队列中插入数据

---

err := db.Table("article").Where("id= ?", id).Update(&article).Error

消费数据

---

db.Transaction(func(tx *gorm.DB) error {
  if err := tx.Select("update article set `status`=1 where `id` =?", id).Error; err != nil {
    return err
  }
  return nil
})

---

具体代码

// ProductMq 生产数据
func (t RabbitMqController) ProductMq(c *gin.Context) {

	var entity database.MessageEntity
	if err := c.ShouldBindJSON(&entity); err != nil {
		c.JSON(400, Response{
			Code: 0,
			Msg:  err.Error(),
			Data: nil,
		})
		return
	}

	go func() {
		defer func() {
			if err := recover(); err != nil {
				logrus.Errorf("publish message fail :%v ", err)
			}
		}()
		var articles []models.Article
		db := database.GetDb()
		err := db.Where("status=1").Limit(10).Select("id").Find(&articles).Error
		if err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				logrus.Errorf("article no data err:%v", err.Error())
				return
			}
			logrus.Errorf("database err:%v", err.Error())
			return
		}
		rabbit := database.GetRabbitMqConn()
		err = rabbit.Channel.Confirm(false)
		if err != nil {
			logrus.Errorf("Failed to enable publisher confirms:%v", err.Error())
			return
		}
		confirms := rabbit.Channel.NotifyPublish(make(chan amqp.Confirmation, len(articles)))
		//defer rabbit.Close()
		for _, data := range articles {
			res, err := json.Marshal(data.Id)
			if err != nil {
				logrus.Errorf("json marshal err:%v", err.Error())
				return
			}
			// TODO: 需要开启confirm模式 手动ack
			if err = rabbit.Channel.Publish(entity.Exchange, entity.Key, false, false, amqp.Publishing{
				DeliveryMode:    amqp.Persistent,
				Headers:         amqp.Table{},
				ContentType:     "text/plain",
				ContentEncoding: "",
				Priority:        entity.Priority,
				Body:            res,
			}); err != nil {
				logrus.Errorf("database err:%v", err.Error())
				return
			}
		}
		select {
		case confirm := <-confirms:
			if !confirm.Ack {
				logrus.Errorf("Failed delivery of message with body...", confirm)
				// 可以在这里实现重试逻辑
				return
			}
		}
	}()

	c.JSON(200, Response{
		Code: 0,
		Msg:  "ok",
		Data: nil,
	})
	return
}

type ConsumeMqReq struct {
	QueueName        string `json:"queueName"`
	Consumer         string `json:"consumer"` // 指定消费者
	HasNewConnection bool   `json:"hasNewConnection"`
}

// ConsumeMq 消费
func (t RabbitMqController) ConsumeMq(c *gin.Context) {

	var req ConsumeMqReq
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(400, Response{
			Code: 0,
			Msg:  err.Error(),
			Data: nil,
		})
		return
	}
	redisClient := database.GetRedisClient()
	go database.ConsumeMessagesWithAck(req.QueueName, func(body amqp.Delivery) error {
		var data int
		err := json.Unmarshal(body.Body, &data)
		if err != nil {
			logrus.Errorf("err:%v", err)
			return err
		}
		// 避免重复消费 可以使用全局唯一字段判断，或者将消费的数据id存入redis
		result, err := redisClient.Get(strconv.Itoa(data)).Result()
		if !errors.Is(err, redis.Nil) {
			logrus.Infof("消息已被消费,忽略 %s", strconv.Itoa(data))
			// _ = body.Reject(false)
			return nil
		}
		if len(result) > 0 {
			logrus.Infof("redis data: %s", result)
		}
		if err := updateArticleData(data); err != nil {
			logrus.Errorf("updateArticleData err:%v", err)
			return err
		}
		return nil
	}, func() {})

	c.JSON(200, Response{
		Code: 0,
		Msg:  "ok",
		Data: nil,
	})
	return
}