优化结构

pkg/mq/mq.go

@@ -10,6 +10,11 @@ import (
 
 var ErrUnavailable = errors.New("message broker unavailable")
 
+const (
+	ProviderEMQX     = "emqx"
+	ProviderRabbitMQ = "rabbitmq"
+)
+
 const (
 	AtMostOnce  byte = 0
 	AtLeastOnce byte = 1
@@ -27,6 +32,37 @@ func (m Message) DecodeJSON(target any) error { return json.Unmarshal(m.Payload,
 
 type Handler func(context.Context, Message)
 
+// TopicSubscription is one logical module subscription. The handler is kept
+// by the runtime and is replayed after a client reconnects or is rebuilt.
+type TopicSubscription struct {
+	Topic   string
+	QoS     byte
+	Handler Handler
+}
+
+// SubscriptionSet is the complete subscription declaration for one module and
+// provider. Registering the same owner/provider replaces its previous set.
+// Owner must be a stable module name, not a request or goroutine identifier.
+type SubscriptionSet struct {
+	Owner    string
+	Provider string
+	Topics   []TopicSubscription
+}
+
+// SubscriptionRegistrar is the module-facing seam for durable-in-process
+// subscription intent. Register does not require a live broker; the runtime
+// will bind the declared topics when the provider becomes available.
+type SubscriptionRegistrar interface {
+	Register(SubscriptionSet) error
+	Unregister(owner string) error
+}
+
+// SubscriptionContributor lets a module expose its broker subscriptions
+// without depending on the concrete integration implementation.
+type SubscriptionContributor interface {
+	RegisterSubscriptions(SubscriptionRegistrar) error
+}
+
 type Client interface {
 	Publish(context.Context, string, []byte, byte, bool) error
 	Subscribe(context.Context, string, byte, Handler) error
@@ -38,6 +74,7 @@ type Client interface {
 // Registry exposes named broker clients while preserving Client as the
 // default EMQX/MQTT boundary for existing modules.
 type Registry interface {
+	SubscriptionRegistrar
 	Client(provider string) Client
 	PublishTo(context.Context, string, string, []byte, byte, bool) error
 	SubscribeTo(context.Context, string, string, byte, Handler) error

pkg/mq/subscription.go

@@ -0,0 +1,55 @@
+package mq
+
+import (
+	"fmt"
+	"strings"
+)
+
+// NormalizeSubscriptionSet validates and canonicalizes a module declaration.
+func NormalizeSubscriptionSet(set SubscriptionSet) (SubscriptionSet, error) {
+	set.Owner = strings.TrimSpace(set.Owner)
+	set.Provider = strings.ToLower(strings.TrimSpace(set.Provider))
+	if set.Owner == "" {
+		return SubscriptionSet{}, fmt.Errorf("mq subscription owner is empty")
+	}
+	if set.Provider != ProviderEMQX && set.Provider != ProviderRabbitMQ {
+		return SubscriptionSet{}, fmt.Errorf("unsupported mq provider %q", set.Provider)
+	}
+	if len(set.Topics) == 0 {
+		return SubscriptionSet{}, fmt.Errorf("mq subscription topics are empty")
+	}
+	seen := make(map[string]struct{}, len(set.Topics))
+	for index := range set.Topics {
+		set.Topics[index].Topic = strings.TrimSpace(set.Topics[index].Topic)
+		if set.Topics[index].Topic == "" {
+			return SubscriptionSet{}, fmt.Errorf("mq subscription topic at index %d is empty", index)
+		}
+		if set.Topics[index].QoS > ExactlyOnce {
+			return SubscriptionSet{}, fmt.Errorf("invalid mq qos %d for topic %q", set.Topics[index].QoS, set.Topics[index].Topic)
+		}
+		if set.Topics[index].Handler == nil {
+			return SubscriptionSet{}, fmt.Errorf("mq subscription handler is nil for topic %q", set.Topics[index].Topic)
+		}
+		if _, exists := seen[set.Topics[index].Topic]; exists {
+			return SubscriptionSet{}, fmt.Errorf("duplicate mq subscription topic %q", set.Topics[index].Topic)
+		}
+		seen[set.Topics[index].Topic] = struct{}{}
+	}
+	return set, nil
+}
+
+// ApplySubscriptions activates dependency-bearing module contributors.
+func ApplySubscriptions(registrar SubscriptionRegistrar, contributors ...SubscriptionContributor) error {
+	if registrar == nil {
+		return fmt.Errorf("mq subscription registrar is nil")
+	}
+	for _, contributor := range contributors {
+		if contributor == nil {
+			continue
+		}
+		if err := contributor.RegisterSubscriptions(registrar); err != nil {
+			return err
+		}
+	}
+	return nil
+}