optimize destinationRule generate (#782)

pkg/ingress/kube/annotations/upstreamtls.go

@@ -65,7 +65,12 @@ func (u upstreamTLS) Parse(annotations Annotations, config *Ingress, _ *GlobalCo
 	}
 
 	defer func() {
-		config.UpstreamTLS = upstreamTLSConfig
+		if upstreamTLSConfig.BackendProtocol == defaultBackendProtocol {
+			// no need destination rule when use HTTP protocol
+			config.UpstreamTLS = nil
+		} else {
+			config.UpstreamTLS = upstreamTLSConfig
+		}
 	}()
 
 	if proto, err := annotations.ParseStringASAP(backendProtocol); err == nil {

pkg/ingress/kube/annotations/upstreamtls_test.go

@@ -33,6 +33,12 @@ func TestUpstreamTLSParse(t *testing.T) {
 			input:  Annotations{},
 			expect: nil,
 		},
+		{
+			input: Annotations{
+				buildNginxAnnotationKey(backendProtocol): "HTTP",
+			},
+			expect: nil,
+		},
 		{
 			input: Annotations{
 				buildNginxAnnotationKey(proxySSLSecret):     "",