feat: only check preferred/fallback protocols availability

reach/client/client.go

@@ -30,58 +30,61 @@ func (c *Client) Protocol(ctx context.Context) (protocol.Identifier, protocol.Op
 
 func (c *Client) getProtocol(ctx context.Context) (protocol.Identifier, protocol.Operations, error) {
 	c.getProtocolOnce.Do(func() {
-		availables, err := c.opts.Protocols.Availables(
+		opts := []protocol.ProtocolOptionFunc{
-			ctx, c.addr, c.opts.AvailableTimeout,
 			protocol.WithProtocolLogger(c.opts.Logger),
 			protocol.WithProtocolDial(c.opts.Dial),
-		)
+		}
+
+		preferred, err := c.opts.Protocols.Get(c.opts.PreferredProtocol, opts...)
+		if err != nil && c.opts.FallbackProtocol == "" {
+			c.getProtocolOnceErr = errors.WithStack(err)
+			return
+		}
+
+		if preferred != nil {
+			preferredCtx, cancel := context.WithTimeout(ctx, c.opts.AvailableTimeout)
+			defer cancel()
+
+			ok, err := preferred.Available(preferredCtx, c.addr)
+			if err != nil && c.opts.FallbackProtocol == "" {
+				c.getProtocolOnceErr = errors.WithStack(err)
+				return
+			}
+
+			if ok {
+				c.proto = preferred.Identifier()
+				c.ops = preferred.Operations(c.addr)
+				return
+			}
+		}
+
+		if c.opts.FallbackProtocol == "" {
+			c.getProtocolOnceErr = errors.WithStack(err)
+			return
+		}
+
+		fallback, err := c.opts.Protocols.Get(c.opts.FallbackProtocol, opts...)
 		if err != nil {
 			c.getProtocolOnceErr = errors.WithStack(err)
 			return
 		}
 
-		var preferred protocol.Protocol
+		fallbackCtx, cancel := context.WithTimeout(ctx, c.opts.AvailableTimeout)
-		var fallback protocol.Protocol
+		defer cancel()
 
-		for _, proto := range availables {
+		ok, err := fallback.Available(fallbackCtx, c.addr)
-			if proto.Identifier() == c.opts.FallbackProtocol {
+		if err != nil && c.opts.FallbackProtocol == "" {
-				fallback = proto
+			c.getProtocolOnceErr = errors.WithStack(err)
-			}
-
-			if proto.Identifier() == c.opts.PreferredProtocol {
-				preferred = proto
-				break
-			}
-		}
-
-		if preferred != nil {
-			c.proto = preferred.Identifier()
-			c.ops = preferred.Operations(c.addr)
 			return
 		}
 
-		if fallback != nil {
+		if ok {
 			c.proto = fallback.Identifier()
 			c.ops = fallback.Operations(c.addr)
 			return
 		}
 
-		for _, proto := range availables {
+		c.getProtocolOnceErr = errors.Errorf("neither preferred protocol '%v' or fallback '%v' are available", c.opts.PreferredProtocol, c.opts.FallbackProtocol)
-			if proto.Identifier() != c.opts.FallbackProtocol {
-				continue
-			}
-
-			fallback = proto
-			break
-		}
-
-		if fallback == nil {
-			c.getProtocolOnceErr = errors.Errorf("neither preferred protocol '%v' or fallback '%v' are available", c.opts.PreferredProtocol, c.opts.FallbackProtocol)
-			return
-		}
-
-		c.proto = fallback.Identifier()
-		c.ops = fallback.Operations(c.addr)
 	})
 	if c.getProtocolOnceErr != nil {
 		return "", nil, errors.WithStack(c.getProtocolOnceErr)

reach/client/protocol/registry.go

@@ -15,6 +15,22 @@ func (r *Registry) Register(identifier Identifier, factory ProtocolFactory) {
 	r.protocols[identifier] = factory
 }
 
+func (r *Registry) Get(identifier Identifier, funcs ...ProtocolOptionFunc) (Protocol, error) {
+	factory, exists := r.protocols[identifier]
+	if !exists {
+		return nil, errors.WithStack(ErrNotFound)
+	}
+
+	protocolOpts := NewProtocolOptions(funcs...)
+
+	proto, err := factory(protocolOpts)
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return proto, nil
+}
+
 func (r *Registry) Availables(ctx context.Context, addr string, timeout time.Duration, funcs ...ProtocolOptionFunc) ([]Protocol, error) {
 	availables := make([]Protocol, 0)
 	protocolOpts := NewProtocolOptions(funcs...)