optimize the DeriveClusterFromDomain function

1. validate domain only for proxy urls
2. use registered target cluster for custom domain extraction

management/internals/modules/reverseproxy/domain/manager/manager.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"net"
-	"net/url"
 	"strings"
 
 	log "github.com/sirupsen/logrus"
@@ -223,57 +222,19 @@ func (m Manager) ValidateDomain(ctx context.Context, accountID, userID, domainID
 }
 
 // proxyURLAllowList retrieves a list of currently connected proxies and
-// their URLs (as reported by the proxy servers). It performs some clean
+// their URLs
-// up on those URLs to attempt to retrieve domain names as we would
-// expect to see them in a validation check.
 func (m Manager) proxyURLAllowList() []string {
 	var reverseProxyAddresses []string
 	if m.proxyURLProvider != nil {
 		reverseProxyAddresses = m.proxyURLProvider.GetConnectedProxyURLs()
 	}
-	var allowedProxyURLs []string
+	return reverseProxyAddresses
-	for _, addr := range reverseProxyAddresses {
-		if addr == "" {
-			continue
-		}
-		host := extractHostFromAddress(addr)
-		if host != "" {
-			allowedProxyURLs = append(allowedProxyURLs, host)
-		}
-	}
-	return allowedProxyURLs
-}
-
-// extractHostFromAddress extracts the hostname from an address string.
-// It handles both URL format (https://host:port) and plain hostname (host or host:port).
-func extractHostFromAddress(addr string) string {
-	// If it looks like a URL with a scheme, parse it
-	if strings.Contains(addr, "://") {
-		proxyUrl, err := url.Parse(addr)
-		if err != nil {
-			log.WithError(err).Debugf("failed to parse proxy URL %s", addr)
-			return ""
-		}
-		host, _, err := net.SplitHostPort(proxyUrl.Host)
-		if err != nil {
-			return proxyUrl.Host
-		}
-		return host
-	}
-
-	// Otherwise treat as hostname or host:port
-	host, _, err := net.SplitHostPort(addr)
-	if err != nil {
-		// No port, use as-is
-		return addr
-	}
-	return host
 }
 
 // DeriveClusterFromDomain determines the proxy cluster for a given domain.
 // For free domains (those ending with a known cluster suffix), the cluster is extracted from the domain.
-// For custom domains, the cluster is determined by looking up the CNAME target.
+// For custom domains, the cluster is determined by checking the registered custom domain's target cluster.
-func (m Manager) DeriveClusterFromDomain(ctx context.Context, domain string) (string, error) {
+func (m Manager) DeriveClusterFromDomain(ctx context.Context, accountID, domain string) (string, error) {
 	allowList := m.proxyURLAllowList()
 	if len(allowList) == 0 {
 		return "", fmt.Errorf("no proxy clusters available")
@@ -283,14 +244,28 @@ func (m Manager) DeriveClusterFromDomain(ctx context.Context, domain string) (st
 		return cluster, nil
 	}
 
-	cluster, valid := m.validator.ValidateWithCluster(ctx, domain, allowList)
+	customDomains, err := m.store.ListCustomDomains(ctx, accountID)
+	if err != nil {
+		return "", fmt.Errorf("list custom domains: %w", err)
+	}
+
+	targetCluster, valid := extractClusterFromCustomDomains(domain, customDomains)
 	if valid {
-		return cluster, nil
+		return targetCluster, nil
 	}
 
 	return "", fmt.Errorf("domain %s does not match any available proxy cluster", domain)
 }
 
+func extractClusterFromCustomDomains(domain string, customDomains []*domain.Domain) (string, bool) {
+	for _, customDomain := range customDomains {
+		if strings.HasSuffix(domain, "."+customDomain.Domain) {
+			return customDomain.TargetCluster, true
+		}
+	}
+	return "", false
+}
+
 // ExtractClusterFromFreeDomain extracts the cluster address from a free domain.
 // Free domains have the format: <name>.<nonce>.<cluster> (e.g., myapp.abc123.eu.proxy.netbird.io)
 // It matches the domain suffix against available clusters and returns the matching cluster.

management/internals/modules/reverseproxy/manager/manager.go

@@ -23,7 +23,7 @@ const unknownHostPlaceholder = "unknown"
 
 // ClusterDeriver derives the proxy cluster from a domain.
 type ClusterDeriver interface {
-	DeriveClusterFromDomain(ctx context.Context, domain string) (string, error)
+	DeriveClusterFromDomain(ctx context.Context, accountID, domain string) (string, error)
 }
 
 type managerImpl struct {
@@ -137,7 +137,7 @@ func (m *managerImpl) CreateService(ctx context.Context, accountID, userID strin
 
 	var proxyCluster string
 	if m.clusterDeriver != nil {
-		proxyCluster, err = m.clusterDeriver.DeriveClusterFromDomain(ctx, service.Domain)
+		proxyCluster, err = m.clusterDeriver.DeriveClusterFromDomain(ctx, accountID, service.Domain)
 		if err != nil {
 			log.WithError(err).Warnf("could not derive cluster from domain %s, updates will broadcast to all proxy servers", service.Domain)
 			return nil, status.Errorf(status.PreconditionFailed, "could not derive cluster from domain %s: %v", service.Domain, err)
@@ -239,7 +239,7 @@ func (m *managerImpl) UpdateService(ctx context.Context, accountID, userID strin
 			}
 
 			if m.clusterDeriver != nil {
-				newCluster, err := m.clusterDeriver.DeriveClusterFromDomain(ctx, service.Domain)
+				newCluster, err := m.clusterDeriver.DeriveClusterFromDomain(ctx, accountID, service.Domain)
 				if err != nil {
 					log.WithError(err).Warnf("could not derive cluster from domain %s", service.Domain)
 				}