[COR-21902] Add dial timeout config for client

memcache/memcache.go

@@ -136,6 +136,11 @@ type Client struct {
 	// If zero, DefaultTimeout is used.
 	Timeout time.Duration
 
+	// DialTimeout specifies the timeout for establishing new connections,
+	// including the TLS handshake if TLS is enabled.
+	// If zero, Timeout is used (for backward compatibility).
+	DialTimeout time.Duration
+
 	// MaxIdleConns specifies the maximum number of idle connections that will
 	// be maintained per address. If less than one, DefaultMaxIdleConns will be
 	// used.
@@ -237,6 +242,14 @@ func (c *Client) netTimeout() time.Duration {
 	return DefaultTimeout
 }
 
+func (c *Client) dialTimeout() time.Duration {
+	if c.DialTimeout != 0 {
+		return c.DialTimeout
+	}
+	// Fall back to Timeout for backward compatibility
+	return c.netTimeout()
+}
+
 func (c *Client) maxIdleConns() int {
 	if c.MaxIdleConns > 0 {
 		return c.MaxIdleConns
@@ -265,7 +278,7 @@ func (c *Client) dial(addr net.Addr) (net.Conn, error) {
 		nc  net.Conn
 		err error
 	)
-	nd := net.Dialer{Timeout: c.netTimeout()}
+	nd := net.Dialer{Timeout: c.dialTimeout()}
 	if c.TlsConfig != nil {
 		nc, err = tls.DialWithDialer(&nd, addr.Network(), addr.String(), c.TlsConfig)
 	} else {

memcache/memcache_test.go

@@ -346,3 +346,126 @@ func TestLocalhostTLS(t *testing.T) {
 	c.TlsConfig = tlsConfig
 	testWithClient(t, c)
 }
+
+// TestDialTimeoutMethod tests the dialTimeout() method logic
+func TestDialTimeoutMethod(t *testing.T) {
+	tests := []struct {
+		name        string
+		dialTimeout time.Duration
+		timeout     time.Duration
+		expected    time.Duration
+	}{
+		{
+			name:        "DialTimeout set, should use DialTimeout",
+			dialTimeout: 500 * time.Millisecond,
+			timeout:     100 * time.Millisecond,
+			expected:    500 * time.Millisecond,
+		},
+		{
+			name:        "DialTimeout zero, should fall back to Timeout",
+			dialTimeout: 0,
+			timeout:     200 * time.Millisecond,
+			expected:    200 * time.Millisecond,
+		},
+		{
+			name:        "Both zero, should use DefaultTimeout",
+			dialTimeout: 0,
+			timeout:     0,
+			expected:    DefaultTimeout,
+		},
+		{
+			name:        "Only DialTimeout set",
+			dialTimeout: 300 * time.Millisecond,
+			timeout:     0,
+			expected:    300 * time.Millisecond,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			c := &Client{
+				DialTimeout: tt.dialTimeout,
+				Timeout:     tt.timeout,
+			}
+			got := c.dialTimeout()
+			if got != tt.expected {
+				t.Errorf("dialTimeout() = %v, want %v", got, tt.expected)
+			}
+		})
+	}
+}
+
+// TestNetTimeoutMethod tests the netTimeout() method remains unchanged
+func TestNetTimeoutMethod(t *testing.T) {
+	tests := []struct {
+		name     string
+		timeout  time.Duration
+		expected time.Duration
+	}{
+		{
+			name:     "Timeout set",
+			timeout:  50 * time.Millisecond,
+			expected: 50 * time.Millisecond,
+		},
+		{
+			name:     "Timeout zero, should use DefaultTimeout",
+			timeout:  0,
+			expected: DefaultTimeout,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			c := &Client{
+				Timeout: tt.timeout,
+			}
+			got := c.netTimeout()
+			if got != tt.expected {
+				t.Errorf("netTimeout() = %v, want %v", got, tt.expected)
+			}
+		})
+	}
+}
+
+// TestBackwardCompatibility verifies old behavior when DialTimeout is not set
+func TestBackwardCompatibility(t *testing.T) {
+	c := &Client{
+		Timeout: 250 * time.Millisecond,
+		// DialTimeout not set (zero value)
+	}
+
+	// dialTimeout() should fall back to netTimeout() which returns Timeout
+	dialTimeout := c.dialTimeout()
+	netTimeout := c.netTimeout()
+
+	if dialTimeout != netTimeout {
+		t.Errorf("Backward compatibility broken: dialTimeout=%v, netTimeout=%v", dialTimeout, netTimeout)
+	}
+
+	if dialTimeout != 250*time.Millisecond {
+		t.Errorf("Expected dialTimeout to be 250ms (from Timeout), got %v", dialTimeout)
+	}
+}
+
+// TestSeparateTimeouts verifies DialTimeout and Timeout can be set independently
+func TestSeparateTimeouts(t *testing.T) {
+	c := &Client{
+		DialTimeout: 500 * time.Millisecond,
+		Timeout:     50 * time.Millisecond,
+	}
+
+	dialTimeout := c.dialTimeout()
+	netTimeout := c.netTimeout()
+
+	if dialTimeout != 500*time.Millisecond {
+		t.Errorf("Expected dialTimeout to be 500ms, got %v", dialTimeout)
+	}
+
+	if netTimeout != 50*time.Millisecond {
+		t.Errorf("Expected netTimeout to be 50ms, got %v", netTimeout)
+	}
+
+	if dialTimeout == netTimeout {
+		t.Error("DialTimeout and Timeout should be independent")
+	}
+}