allow configuring register action for nats

Signed-off-by: jkoberg <[email protected]>

v4/registry/nats/nats.go

@@ -14,11 +14,12 @@ import (
 )
 
 type natsRegistry struct {
-	addrs      []string
-	opts       registry.Options
-	nopts      nats.Options
-	queryTopic string
-	watchTopic string
+	addrs          []string
+	opts           registry.Options
+	nopts          nats.Options
+	queryTopic     string
+	watchTopic     string
+	registerAction string
 
 	sync.RWMutex
 	conn      *nats.Conn
@@ -27,8 +28,9 @@ type natsRegistry struct {
 }
 
 var (
-	defaultQueryTopic = "micro.registry.nats.query"
-	defaultWatchTopic = "micro.registry.nats.watch"
+	defaultQueryTopic     = "micro.registry.nats.query"
+	defaultWatchTopic     = "micro.registry.nats.watch"
+	defaultRegisterAction = "create"
 )
 
 func init() {
@@ -55,6 +57,11 @@ func configure(n *natsRegistry, opts ...registry.Option) error {
 		watchTopic = wt
 	}
 
+	registerAction := defaultRegisterAction
+	if ra, ok := n.opts.Context.Value(registerActionKey{}).(string); ok {
+		registerAction = ra
+	}
+
 	// registry.Options have higher priority than nats.Options
 	// only if Addrs, Secure or TLSConfig were not set through a registry.Option
 	// we read them from nats.Option
@@ -78,6 +85,7 @@ func configure(n *natsRegistry, opts ...registry.Option) error {
 	n.nopts = natsOptions
 	n.queryTopic = queryTopic
 	n.watchTopic = watchTopic
+	n.registerAction = registerAction
 
 	return nil
 }
@@ -322,7 +330,7 @@ func (n *natsRegistry) Register(s *registry.Service, opts ...registry.RegisterOp
 		return err
 	}
 
-	b, err := json.Marshal(&registry.Result{Action: "create", Service: s})
+	b, err := json.Marshal(&registry.Result{Action: n.registerAction, Service: s})
 	if err != nil {
 		return err
 	}

v4/registry/nats/options.go

@@ -11,6 +11,7 @@ type contextQuorumKey struct{}
 type optionsKey struct{}
 type watchTopicKey struct{}
 type queryTopicKey struct{}
+type registerActionKey struct{}
 
 var (
 	DefaultQuorum = 0
@@ -70,3 +71,17 @@ func WatchTopic(s string) registry.Option {
 		o.Context = context.WithValue(o.Context, watchTopicKey{}, s)
 	}
 }
+
+// RegisterAction allows to set the action to use when registering to nats.
+// As of now there are three different options:
+// - "create" (default) only registers if there is noone already registered under the same key.
+// - "update" only updates the registration if it already exists.
+// - "put" creates or updates a registration
+func RegisterAction(s string) registry.Option {
+	return func(o *registry.Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, registerActionKey{}, s)
+	}
+}