优化结构

pkg/mq/mq.go

@@ -0,0 +1,58 @@
+// Package mq exposes the broker-agnostic messaging seam used by services.
+package mq
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"time"
+)
+
+var ErrUnavailable = errors.New("message broker unavailable")
+
+const (
+	AtMostOnce  byte = 0
+	AtLeastOnce byte = 1
+	ExactlyOnce byte = 2
+)
+
+type Message struct {
+	Topic   string
+	Payload []byte
+	QoS     byte
+	Retain  bool
+}
+
+func (m Message) DecodeJSON(target any) error { return json.Unmarshal(m.Payload, target) }
+
+type Handler func(context.Context, Message)
+
+type Client interface {
+	Publish(context.Context, string, []byte, byte, bool) error
+	Subscribe(context.Context, string, byte, Handler) error
+	Unsubscribe(context.Context, ...string) error
+	Connected() bool
+	Close() error
+}
+
+type Config struct {
+	Enabled        bool
+	Broker         string
+	ClientID       string
+	Username       string
+	Password       string
+	KeepAlive      time.Duration
+	CleanSession   bool
+	ConnectTimeout time.Duration
+}
+
+func PublishJSON(ctx context.Context, client Client, topic string, value any, qos byte, retain bool) error {
+	if client == nil {
+		return ErrUnavailable
+	}
+	payload, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+	return client.Publish(ctx, topic, payload, qos, retain)
+}