[relay] Use instanceURL instead of Exposed address. (#4905)

Replaces string-based exposed address handling with URL-based InstanceURL() (type url.URL) across relay/server and relay/healthcheck; adds SchemeREL/SchemeRELS constants; updates getInstanceURL to return *url.URL with scheme and TLS validation; adjusts WS dialing and health-check logic to use URL fields.

Author: pappz

relay/cmd/root.go

@@ -160,7 +160,8 @@ func execute(cmd *cobra.Command, args []string) error {
 		log.Debugf("failed to create relay server: %v", err)
 		return fmt.Errorf("failed to create relay server: %v", err)
 	}
-	log.Infof("server will be available on: %s", srv.InstanceURL())
+	instanceURL := srv.InstanceURL()
+	log.Infof("server will be available on: %s", instanceURL.String())
 	wg.Add(1)
 	go func() {
 		defer wg.Done()

relay/healthcheck/healthcheck.go

@@ -6,13 +6,14 @@ import (
 	"errors"
 	"net"
 	"net/http"
-	"strings"
+	"net/url"
 	"sync"
 	"time"
 
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/relay/protocol"
+	"github.com/netbirdio/netbird/relay/server"
 )
 
 const (
@@ -26,7 +27,7 @@ const (
 
 type ServiceChecker interface {
 	ListenerProtocols() []protocol.Protocol
-	ExposedAddress() string
+	InstanceURL() url.URL
 }
 
 type HealthStatus struct {
@@ -134,7 +135,7 @@ func (s *Server) getHealthStatus(ctx context.Context) (*HealthStatus, bool) {
 	}
 	status.Listeners = listeners
 
-	if !strings.HasPrefix(s.config.ServiceChecker.ExposedAddress(), "rels") {
+	if s.config.ServiceChecker.InstanceURL().Scheme != server.SchemeRELS {
 		status.CertificateValid = false
 	}
 
@@ -156,14 +157,9 @@ func (s *Server) validateListeners() ([]protocol.Protocol, bool) {
 }
 
 func (s *Server) validateConnection(ctx context.Context) bool {
-	exposedAddress := s.config.ServiceChecker.ExposedAddress()
-	if exposedAddress == "" {
-		log.Error("exposed address is empty, cannot validate certificate")
-		return false
-	}
-
-	if err := dialWS(ctx, exposedAddress); err != nil {
-		log.Errorf("failed to dial WebSocket listener at %s: %v", exposedAddress, err)
+	addr := s.config.ServiceChecker.InstanceURL()
+	if err := dialWS(ctx, addr); err != nil {
+		log.Errorf("failed to dial WebSocket listener at %s: %v", addr.String(), err)
 		return false
 	}
 

relay/healthcheck/ws.go

@@ -3,22 +3,22 @@ package healthcheck
 import (
 	"context"
 	"fmt"
-	"strings"
+	"net/url"
 
 	"github.com/coder/websocket"
 
+	"github.com/netbirdio/netbird/relay/server"
 	"github.com/netbirdio/netbird/shared/relay"
 )
 
-func dialWS(ctx context.Context, address string) error {
-	addressSplit := strings.Split(address, "/")
+func dialWS(ctx context.Context, address url.URL) error {
 	scheme := "ws"
-	if addressSplit[0] == "rels:" {
+	if address.Scheme == server.SchemeRELS {
 		scheme = "wss"
 	}
-	url := fmt.Sprintf("%s://%s%s", scheme, addressSplit[2], relay.WebSocketURLPath)
+	wsURL := fmt.Sprintf("%s://%s%s", scheme, address.Host, relay.WebSocketURLPath)
 
-	conn, resp, err := websocket.Dial(ctx, url, nil)
+	conn, resp, err := websocket.Dial(ctx, wsURL, nil)
 	if resp != nil {
 		defer func() {
 			if resp.Body != nil {

relay/server/relay.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net"
+	"net/url"
 	"sync"
 	"time"
 
@@ -22,7 +23,7 @@ type Config struct {
 	TLSSupport     bool
 	AuthValidator  Validator
 
-	instanceURL string
+	instanceURL url.URL
 }
 
 func (c *Config) validate() error {
@@ -37,7 +38,7 @@ func (c *Config) validate() error {
 	if err != nil {
 		return fmt.Errorf("invalid url: %v", err)
 	}
-	c.instanceURL = instanceURL
+	c.instanceURL = *instanceURL
 
 	if c.AuthValidator == nil {
 		return fmt.Errorf("auth validator is required")
@@ -53,7 +54,7 @@ type Relay struct {
 
 	store          *store.Store
 	notifier       *store.PeerNotifier
-	instanceURL    string
+	instanceURL    url.URL
 	exposedAddress string
 	preparedMsg    *preparedMsg
 
@@ -97,7 +98,7 @@ func NewRelay(config Config) (*Relay, error) {
 		notifier:       store.NewPeerNotifier(),
 	}
 
-	r.preparedMsg, err = newPreparedMsg(r.instanceURL)
+	r.preparedMsg, err = newPreparedMsg(r.instanceURL.String())
 	if err != nil {
 		metricsCancel()
 		return nil, fmt.Errorf("prepare message: %v", err)
@@ -177,11 +178,6 @@ func (r *Relay) Shutdown(ctx context.Context) {
 }
 
 // InstanceURL returns the instance URL of the relay server
-func (r *Relay) InstanceURL() string {
+func (r *Relay) InstanceURL() url.URL {
 	return r.instanceURL
 }
-
-// ExposedAddress returns the exposed address (domain:port) where clients connect
-func (r *Relay) ExposedAddress() string {
-	return r.exposedAddress
-}

relay/server/server.go

@@ -3,6 +3,7 @@ package server
 import (
 	"context"
 	"crypto/tls"
+	"net/url"
 	"sync"
 
 	"github.com/hashicorp/go-multierror"
@@ -39,7 +40,7 @@ type Server struct {
 //
 //	config: A Config struct containing the necessary configuration:
 //	  - Meter: An OpenTelemetry metric.Meter used for recording metrics. If nil, a default no-op meter is used.
-//	  - ExposedAddress: The public address (in domain:port format) used as the server's instance URL. Required.
+//	  - InstanceURL: The public address (in domain:port format) used as the server's instance URL. Required.
 //	  - TLSSupport: A boolean indicating whether TLS is enabled for the server.
 //	  - AuthValidator: A Validator used to authenticate peers. Required.
 //
@@ -119,11 +120,6 @@ func (r *Server) Shutdown(ctx context.Context) error {
 	return nberrors.FormatErrorOrNil(multiErr)
 }
 
-// InstanceURL returns the instance URL of the relay server.
-func (r *Server) InstanceURL() string {
-	return r.relay.instanceURL
-}
-
 func (r *Server) ListenerProtocols() []protocol.Protocol {
 	result := make([]protocol.Protocol, 0)
 
@@ -135,6 +131,6 @@ func (r *Server) ListenerProtocols() []protocol.Protocol {
 	return result
 }
 
-func (r *Server) ExposedAddress() string {
-	return r.relay.ExposedAddress()
+func (r *Server) InstanceURL() url.URL {
+	return r.relay.InstanceURL()
 }

relay/server/url.go

@@ -6,9 +6,14 @@ import (
 	"strings"
 )
 
+const (
+	SchemeREL  = "rel"
+	SchemeRELS = "rels"
+)
+
 // getInstanceURL checks if user supplied a URL scheme otherwise adds to the
 // provided address according to TLS definition and parses the address before returning it
-func getInstanceURL(exposedAddress string, tlsSupported bool) (string, error) {
+func getInstanceURL(exposedAddress string, tlsSupported bool) (*url.URL, error) {
 	addr := exposedAddress
 	split := strings.Split(exposedAddress, "://")
 	switch {
@@ -17,17 +22,22 @@ func getInstanceURL(exposedAddress string, tlsSupported bool) (string, error) {
 	case len(split) == 1 && !tlsSupported:
 		addr = "rel://" + exposedAddress
 	case len(split) > 2:
-		return "", fmt.Errorf("invalid exposed address: %s", exposedAddress)
+		return nil, fmt.Errorf("invalid exposed address: %s", exposedAddress)
 	}
 
 	parsedURL, err := url.ParseRequestURI(addr)
 	if err != nil {
-		return "", fmt.Errorf("invalid exposed address: %v", err)
+		return nil, fmt.Errorf("invalid exposed address: %v", err)
+	}
+
+	if parsedURL.Scheme != SchemeREL && parsedURL.Scheme != SchemeRELS {
+		return nil, fmt.Errorf("invalid scheme: %s", parsedURL.Scheme)
 	}
 
-	if parsedURL.Scheme != "rel" && parsedURL.Scheme != "rels" {
-		return "", fmt.Errorf("invalid scheme: %s", parsedURL.Scheme)
+	// Validate scheme matches TLS configuration
+	if tlsSupported && parsedURL.Scheme == SchemeREL {
+		return nil, fmt.Errorf("non-TLS scheme '%s' provided but TLS is supported", SchemeREL)
 	}
 
-	return parsedURL.String(), nil
+	return parsedURL, nil
 }

relay/server/relay_test.go renamed to relay/server/url_test.go

@@ -13,7 +13,7 @@ func TestGetInstanceURL(t *testing.T) {
 		{"Valid address with TLS", "example.com", true, "rels://example.com", false},
 		{"Valid address without TLS", "example.com", false, "rel://example.com", false},
 		{"Valid address with scheme", "rel://example.com", false, "rel://example.com", false},
-		{"Valid address with non TLS scheme and TLS true", "rel://example.com", true, "rel://example.com", false},
+		{"Invalid address with non TLS scheme and TLS true", "rel://example.com", true, "", true},
 		{"Valid address with TLS scheme", "rels://example.com", true, "rels://example.com", false},
 		{"Valid address with TLS scheme and TLS false", "rels://example.com", false, "rels://example.com", false},
 		{"Valid address with TLS scheme and custom port", "rels://example.com:9300", true, "rels://example.com:9300", false},
@@ -28,8 +28,11 @@ func TestGetInstanceURL(t *testing.T) {
 			if (err != nil) != tt.expectError {
 				t.Errorf("expected error: %v, got: %v", tt.expectError, err)
 			}
-			if url != tt.expectedURL {
-				t.Errorf("expected URL: %s, got: %s", tt.expectedURL, url)
+			if !tt.expectError && url != nil && url.String() != tt.expectedURL {
+				t.Errorf("expected URL: %s, got: %s", tt.expectedURL, url.String())
+			}
+			if tt.expectError && url != nil {
+				t.Errorf("expected nil URL on error, got: %s", url.String())
 			}
 		})
 	}