fix(network): use RemoteAddr for consistent hashing key (#599)

Author: sinadarbouy

network/consistenthash.go

@@ -45,7 +45,9 @@ func (ch *ConsistentHash) NextProxy(conn IConnWrapper) (IProxy, *gerr.GatewayDEr
 		}
 		key = sourceIP
 	} else {
-		key = conn.LocalAddr().String() // Fallback to use full address as the key if `useSourceIp` is false
+		// Fallback to using the full remote address (IP:port) as the key if `useSourceIP` is false.
+		// This effectively disables consistent hashing, as the remote address has a random port each time.
+		key = conn.RemoteAddr().String()
 	}
 
 	hash := hashKey(key)
@@ -74,10 +76,10 @@ func hashKey(key string) uint64 {
 	return murmur3.Sum64([]byte(key))
 }
 
-// extractIPFromConn extracts the IP address from the connection's local address. It splits the address
+// extractIPFromConn extracts the IP address from the connection's remote address. It splits the address
 // into IP and port components and returns the IP part. This is useful for hashing based on the source IP.
 func extractIPFromConn(con IConnWrapper) (string, error) {
-	addr := con.LocalAddr().String()
+	addr := con.RemoteAddr().String() // RemoteAddr is the address of the request, LocalAddress is the gateway address.
 	// addr will be in the format "IP:port"
 	ip, _, err := net.SplitHostPort(addr)
 	if err != nil {

network/consistenthash_test.go

@@ -42,9 +42,9 @@ func TestConsistentHashNextProxyUseSourceIpExists(t *testing.T) {
 	consistentHash := NewConsistentHash(server, originalStrategy)
 	mockConn := new(MockConnWrapper)
 
-	// Mock LocalAddr to return a specific IP:port format
+	// Mock RemoteAddr to return a specific IP:port format
 	mockAddr := &net.TCPAddr{IP: net.ParseIP("192.168.1.1"), Port: 1234}
-	mockConn.On("LocalAddr").Return(mockAddr)
+	mockConn.On("RemoteAddr").Return(mockAddr)
 
 	key := "192.168.1.1"
 	hash := hashKey(key)
@@ -77,9 +77,9 @@ func TestConsistentHashNextProxyUseFullAddress(t *testing.T) {
 	}
 	mockStrategy := NewRoundRobin(server)
 
-	// Mock LocalAddr to return full address
+	// Mock RemoteAddr to return full address
 	mockAddr := &net.TCPAddr{IP: net.ParseIP("192.168.1.1"), Port: 1234}
-	mockConn.On("LocalAddr").Return(mockAddr)
+	mockConn.On("RemoteAddr").Return(mockAddr)
 
 	consistentHash := NewConsistentHash(server, mockStrategy)
 
@@ -120,8 +120,8 @@ func TestConsistentHashNextProxyConcurrency(t *testing.T) {
 	// Mock IP addresses
 	mockAddr1 := &net.TCPAddr{IP: net.ParseIP("192.168.1.1"), Port: 1234}
 	mockAddr2 := &net.TCPAddr{IP: net.ParseIP("192.168.1.2"), Port: 1234}
-	conn1.On("LocalAddr").Return(mockAddr1)
-	conn2.On("LocalAddr").Return(mockAddr2)
+	conn1.On("RemoteAddr").Return(mockAddr1)
+	conn2.On("RemoteAddr").Return(mockAddr2)
 
 	// Initialize the ConsistentHash
 	consistentHash := NewConsistentHash(server, originalStrategy)