Go语言消息队列事务：Exactly-Once与At-Least-Once语义

Go语言消息队列事务Exactly-Once与At-Least-Once语义1. 消息语义消息队列有三种传递语义At-Most-Once最多一次、At-Least-Once至少一次和Exactly-Once恰好一次。type DeliverySemantics int const ( AtMostOnce DeliverySemantics 1 AtLeastOnce DeliverySemantics 2 ExactlyOnce DeliverySemantics 3 )2. At-Least-Once实现At-Least-Once需要消费者进行消息确认。type AtLeastOnceConsumer struct { consumer *RabbitMQConsumer processed map[string]bool mu sync.RWMutex } func NewAtLeastOnceConsumer(consumer *RabbitMQConsumer) *AtLeastOnceConsumer { return AtLeastOnceConsumer{ consumer: consumer, processed: make(map[string]bool), } } func (c *AtLeastOnceConsumer) Process(ctx context.Context, handler func([]byte) error) error { return c.consumer.ConsumeWithContext(ctx, func(msg []byte) error { msgID : generateMsgID(msg) c.mu.RLock() if c.processed[msgID] { c.mu.RUnlock() return nil } c.mu.RUnlock() if err : handler(msg); err ! nil { return err } c.mu.Lock() c.processed[msgID] true c.mu.Unlock() return nil }) } func generateMsgID(msg []byte) string { h : fnv.New32a() h.Write(msg) return fmt.Sprintf(%d-%d, time.Now().UnixNano(), h.Sum32()) }3. Exactly-Once实现Exactly-Once需要生产者和消费者配合通过事务和幂等性保证。type ExactlyOnceProducer struct { producer *RabbitMQProducer txn *amqp.Tx } func (p *ExactlyOnceProducer) PublishWithTransaction(ctx context.Context, routingKey string, body []byte) error { if p.txn nil { tx, err : p.producer.conn.Channel().Tx() if err ! nil { return err } p.txn tx } err : p.producer.conn.Channel().PublishWithContext( ctx, p.exchange, routingKey, false, false, amqp.Publishing{ ContentType: application/json, Body: body, DeliveryMode: amqp.Persistent, }, ) if err ! nil { p.txn.Rollback() return err } return p.txn.Commit() } type IdempotentHandler struct { storage map[string]bool mu sync.RWMutex } func NewIdempotentHandler() *IdempotentHandler { return IdempotentHandler{ storage: make(map[string]bool), } } func (h *IdempotentHandler) Handle(msgID string, handler func() error) error { h.mu.RLock() if h.storage[msgID] { h.mu.RUnlock() return nil } h.mu.RUnlock() if err : handler(); err ! nil { return err } h.mu.Lock() h.storage[msgID] true h.mu.Unlock() return nil }4. 总结本文介绍了At-Least-Once和Exactly-Once消息语义的实现方法开发者应根据业务需求选择合适的传递语义。