fix host

weed/mq/kafka/gateway/server.go

@@ -11,6 +11,42 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/mq/kafka/protocol"
 )
 
+// resolveAdvertisedAddress resolves the appropriate address to advertise to Kafka clients
+// when the server binds to all interfaces (:: or 0.0.0.0)
+func resolveAdvertisedAddress() string {
+	// Try to find a non-loopback interface
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		glog.V(1).Infof("Failed to get network interfaces, using localhost: %v", err)
+		return "127.0.0.1"
+	}
+
+	for _, iface := range interfaces {
+		// Skip loopback and inactive interfaces
+		if iface.Flags&net.FlagLoopback != 0 || iface.Flags&net.FlagUp == 0 {
+			continue
+		}
+
+		addrs, err := iface.Addrs()
+		if err != nil {
+			continue
+		}
+
+		for _, addr := range addrs {
+			if ipNet, ok := addr.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
+				// Prefer IPv4 addresses for better Kafka client compatibility
+				if ipv4 := ipNet.IP.To4(); ipv4 != nil {
+					return ipv4.String()
+				}
+			}
+		}
+	}
+
+	// Fallback to localhost if no suitable interface found
+	glog.V(1).Infof("No non-loopback interface found, using localhost")
+	return "127.0.0.1"
+}
+
 type Options struct {
 	Listen       string
 	AgentAddress string // Optional: SeaweedMQ Agent address for production mode
@@ -136,17 +172,17 @@ func (s *Server) GetListenerAddr() (string, int) {
 	if strings.HasPrefix(addr, "[::]:") {
 		port := strings.TrimPrefix(addr, "[::]:") 
 		if p, err := strconv.Atoi(port); err == nil {
-			// Revert to 127.0.0.1 for broader compatibility  
-			return "127.0.0.1", p
+			// Resolve appropriate address when bound to IPv6 all interfaces
+			return resolveAdvertisedAddress(), p
 		}
 	}
 	
 	// Handle host:port format
 	if host, port, err := net.SplitHostPort(addr); err == nil {
 		if p, err := strconv.Atoi(port); err == nil {
-			// Use 127.0.0.1 instead of localhost for better kafka-go compatibility
-			if host == "::" || host == "" {
-				host = "127.0.0.1"
+			// Resolve appropriate address when bound to all interfaces
+			if host == "::" || host == "" || host == "0.0.0.0" {
+				host = resolveAdvertisedAddress()
 			}
 			return host, p
 		}

weed/mq/kafka/gateway/server_test.go

@@ -2,6 +2,7 @@ package gateway
 
 import (
     "net"
+    "strings"
     "testing"
     "time"
 )
@@ -29,4 +30,58 @@ func TestServerStartAndClose(t *testing.T) {
     }
 }
 
+func TestGetListenerAddr(t *testing.T) {
+    // Test with localhost binding - should return the actual address
+    srv := NewServer(Options{Listen: "127.0.0.1:0"})
+    if err := srv.Start(); err != nil {
+        t.Fatalf("start: %v", err)
+    }
+    defer srv.Close()
+    
+    host, port := srv.GetListenerAddr()
+    if host != "127.0.0.1" {
+        t.Errorf("expected 127.0.0.1, got %s", host)
+    }
+    if port <= 0 {
+        t.Errorf("expected valid port, got %d", port)
+    }
+    
+    // Test IPv6 all interfaces binding - should resolve to non-loopback IP
+    srv6 := NewServer(Options{Listen: "[::]:0"})
+    if err := srv6.Start(); err != nil {
+        t.Fatalf("start IPv6: %v", err)
+    }
+    defer srv6.Close()
+    
+    host6, port6 := srv6.GetListenerAddr()
+    // Should not be localhost when bound to all interfaces
+    if host6 == "localhost" {
+        t.Errorf("IPv6 all interfaces should not resolve to localhost, got %s", host6)
+    }
+    if port6 <= 0 {
+        t.Errorf("expected valid port, got %d", port6)
+    }
+    t.Logf("IPv6 all interfaces resolved to: %s:%d", host6, port6)
+}
+
+func TestResolveAdvertisedAddress(t *testing.T) {
+    addr := resolveAdvertisedAddress()
+    if addr == "" {
+        t.Error("resolveAdvertisedAddress returned empty string")
+    }
+    
+    // Should be a valid IP address
+    ip := net.ParseIP(addr)
+    if ip == nil {
+        t.Errorf("resolveAdvertisedAddress returned invalid IP: %s", addr)
+    }
+    
+    // Should not be IPv6 (we prefer IPv4 for Kafka compatibility)
+    if strings.Contains(addr, ":") {
+        t.Errorf("Expected IPv4 address, got IPv6: %s", addr)
+    }
+    
+    t.Logf("Resolved advertised address: %s", addr)
+}
+