Registration Retry / Interval (#1651)

* Change the default ttl to 90 seconds

* add retries to registration

* Add retry to web register

server/rpc_server.go

@@ -20,6 +20,7 @@ import (
 	"github.com/micro/go-micro/v2/registry"
 	"github.com/micro/go-micro/v2/transport"
 	"github.com/micro/go-micro/v2/util/addr"
+	"github.com/micro/go-micro/v2/util/backoff"
 	mnet "github.com/micro/go-micro/v2/util/net"
 	"github.com/micro/go-micro/v2/util/socket"
 )
@@ -514,18 +515,39 @@ func (s *rpcServer) Subscribe(sb Subscriber) error {
 }
 
 func (s *rpcServer) Register() error {
-
 	s.RLock()
 	rsvc := s.rsvc
 	config := s.Options()
 	s.RUnlock()
 
-	if rsvc != nil {
+	regFunc := func(service *registry.Service) error {
+		// create registry options
 		rOpts := []registry.RegisterOption{registry.RegisterTTL(config.RegisterTTL)}
-		if err := config.Registry.Register(rsvc, rOpts...); err != nil {
-			return err
+
+		var regErr error
+
+		for i := 0; i < 3; i++ {
+			// attempt to register
+			if err := config.Registry.Register(service, rOpts...); err != nil {
+				// set the error
+				regErr = err
+				// backoff then retry
+				time.Sleep(backoff.Do(i + 1))
+				continue
+			}
+			// success so nil error
+			regErr = nil
+			break
 		}
 
+		return regErr
+	}
+
+	// have we registered before?
+	if rsvc != nil {
+		if err := regFunc(rsvc); err != nil {
+			return err
+		}
 		return nil
 	}
 
@@ -635,10 +657,8 @@ func (s *rpcServer) Register() error {
 		}
 	}
 
-	// create registry options
-	rOpts := []registry.RegisterOption{registry.RegisterTTL(config.RegisterTTL)}
-
-	if err := config.Registry.Register(service, rOpts...); err != nil {
+	// register the service
+	if err := regFunc(service); err != nil {
 		return err
 	}