Initial QSfera import

Server/pkg/natsjsregistry/watcher.go

@@ -0,0 +1,78 @@
+package natsjsregistry
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+
+	natsjskv "github.com/go-micro/plugins/v4/store/nats-js-kv"
+	"github.com/nats-io/nats.go"
+	"go-micro.dev/v4/registry"
+)
+
+// NatsWatcher is the watcher of the nats interface
+type NatsWatcher interface {
+	WatchAll(bucket string, opts ...nats.WatchOpt) (<-chan *natsjskv.StoreUpdate, func() error, error)
+}
+
+// Watcher is used to keep track of changes in the registry
+type Watcher struct {
+	updates <-chan *natsjskv.StoreUpdate
+	stop    func() error
+	reg     *storeregistry
+}
+
+// NewWatcher returns a new watcher
+func NewWatcher(s *storeregistry) (*Watcher, error) {
+	w, ok := s.store.(NatsWatcher)
+	if !ok {
+		return nil, errors.New("store does not implement watcher interface")
+	}
+
+	watcher, stop, err := w.WatchAll("service-registry")
+	if err != nil {
+		return nil, err
+	}
+
+	return &Watcher{
+		updates: watcher,
+		stop:    stop,
+		reg:     s,
+	}, nil
+}
+
+// Next returns the next result. It is a blocking call
+func (w *Watcher) Next() (*registry.Result, error) {
+	kve := <-w.updates
+	if kve == nil {
+		return nil, errors.New("watcher stopped")
+	}
+
+	var svc registry.Service
+	if kve.Value.Data == nil {
+		// fake a service
+		parts := strings.SplitN(kve.Value.Key, _serviceDelimiter, 3)
+		if len(parts) != 3 {
+			return nil, errors.New("invalid service key")
+		}
+		svc.Name = parts[0]
+		// КуСфера registers nodes with a - separator
+		svc.Nodes = []*registry.Node{{Id: parts[0] + "-" + parts[1]}}
+		svc.Version = parts[2]
+	} else {
+		if err := json.Unmarshal(kve.Value.Data, &svc); err != nil {
+			_ = w.stop()
+			return nil, err
+		}
+	}
+
+	return &registry.Result{
+		Service: &svc,
+		Action:  kve.Action,
+	}, nil
+}
+
+// Stop stops the watcher
+func (w *Watcher) Stop() {
+	_ = w.stop()
+}