registry: gossip unify registry option passing, optimize

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

registry/gossip/options.go

@@ -12,34 +12,35 @@ type contextSecretKey struct{}
 // Secret specifies an encryption key. The value should be either
 // 16, 24, or 32 bytes to select AES-128, AES-192, or AES-256.
 func Secret(k []byte) registry.Option {
-	return func(o *registry.Options) {
-		o.Context = context.WithValue(o.Context, contextSecretKey{}, k)
-	}
+	return setRegistryOption(contextSecretKey{}, k)
 }
 
 type contextAddress struct{}
 
 // Address to bind to - host:port
 func Address(a string) registry.Option {
-	return func(o *registry.Options) {
-		o.Context = context.WithValue(o.Context, contextAddress{}, a)
-	}
+	return setRegistryOption(contextAddress{}, a)
 }
 
 type contextConfig struct{}
 
 // Config allow to inject a *memberlist.Config struct for configuring gossip
 func Config(c *memberlist.Config) registry.Option {
-	return func(o *registry.Options) {
-		o.Context = context.WithValue(o.Context, contextConfig{}, c)
-	}
+	return setRegistryOption(contextConfig{}, c)
 }
 
 type contextAdvertise struct{}
 
 // The address to advertise for other gossip members - host:port
 func Advertise(a string) registry.Option {
-	return func(o *registry.Options) {
-		o.Context = context.WithValue(o.Context, contextAdvertise{}, a)
-	}
+	return setRegistryOption(contextAdvertise{}, a)
+}
+
+type contextContext struct{}
+
+// Context specifies a context for the registry.
+// Can be used to signal shutdown of the registry.
+// Can be used for extra option values.
+func Context(ctx context.Context) registry.Option {
+	return setRegistryOption(contextContext{}, ctx)
 }