replication: add GoCDK PubSub support

weed/replication/sub/notification_gocdk_pub_sub.go

@@ -0,0 +1,50 @@
+package sub
+
+import (
+	"context"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+	"github.com/golang/protobuf/proto"
+	"gocloud.dev/pubsub"
+	_ "gocloud.dev/pubsub/awssnssqs"
+	_ "gocloud.dev/pubsub/azuresb"
+	_ "gocloud.dev/pubsub/gcppubsub"
+	_ "gocloud.dev/pubsub/natspubsub"
+	_ "gocloud.dev/pubsub/rabbitpubsub"
+)
+
+func init() {
+	NotificationInputs = append(NotificationInputs, &GoCDKPubSubInput{})
+}
+
+type GoCDKPubSubInput struct {
+	sub *pubsub.Subscription
+}
+
+func (k *GoCDKPubSubInput) GetName() string {
+	return "gocdk_pub_sub"
+}
+
+func (k *GoCDKPubSubInput) Initialize(config util.Configuration) error {
+	subURL := config.GetString("sub_url")
+	glog.V(0).Infof("notification.gocdk_pub_sub.topic_url: %v", subURL)
+	sub, err := pubsub.OpenSubscription(context.Background(), subURL)
+	if err != nil {
+		return err
+	}
+	k.sub = sub
+	return nil
+}
+
+func (k *GoCDKPubSubInput) ReceiveMessage() (key string, message *filer_pb.EventNotification, err error) {
+	msg, err := k.sub.Receive(context.Background())
+	key = msg.Metadata["key"]
+	message = &filer_pb.EventNotification{}
+	err = proto.Unmarshal(msg.Body, message)
+	if err != nil {
+		return "", nil, err
+	}
+	return key, message, nil
+}