add minimalsub interface

pubsub.go

@@ -24,6 +24,15 @@ import (
 
 var log = logging.Logger("pubsub-valuestore")
 
+// MinimalPubsub allows us to provide the bare minimum pubsub functionality
+// to the router, while still using the same pubsub instance in other goroutines.
+// This is primarily done to allow callers to not have to worry about topic management
+// due to topics only allowing a single "joiner".
+type MinimalPubsub interface {
+	RegisterTopicValidator(topic string, val pubsub.Validator, opts ...pubsub.ValidatorOpt) error
+	Join(topic string, opts ...pubsub.TopicOpt) (*pubsub.Topic, error)
+}
+
 type watchGroup struct {
 	// Note: this chan must be buffered, see notifyWatchers
 	listeners map[chan []byte]struct{}
@@ -32,7 +41,7 @@ type watchGroup struct {
 type PubsubValueStore struct {
 	ctx context.Context
 	ds  ds.Datastore
-	ps  *pubsub.PubSub
+	ps  MinimalPubsub
 
 	host  host.Host
 	fetch *fetchProtocol
@@ -72,7 +81,7 @@ func KeyToTopic(key string) string {
 type Option func(*PubsubValueStore) error
 
 // NewPubsubValueStore constructs a new ValueStore that gets and receives records through pubsub.
-func NewPubsubValueStore(ctx context.Context, host host.Host, ps *pubsub.PubSub, validator record.Validator, opts ...Option) (*PubsubValueStore, error) {
+func NewPubsubValueStore(ctx context.Context, host host.Host, ps MinimalPubsub, validator record.Validator, opts ...Option) (*PubsubValueStore, error) {
 	psValueStore := &PubsubValueStore{
 		ctx: ctx,