Disable router when a rule has an error

pkg/rules/rules.go

@@ -59,7 +59,14 @@ func (r *Router) AddRoute(rule string, priority int, handler http.Handler) error
 	}
 
 	route := r.NewRoute().Handler(handler).Priority(priority)
-	return addRuleOnRoute(route, buildTree())
+
+	err = addRuleOnRoute(route, buildTree())
+	if err != nil {
+		route.BuildOnly()
+		return err
+	}
+
+	return nil
 }
 
 type tree struct {

pkg/rules/rules_test.go

@@ -29,6 +29,16 @@ func Test_addRoute(t *testing.T) {
 			rule:          "rulewithnotmatcher",
 			expectedError: true,
 		},
+		{
+			desc:          "Host empty",
+			rule:          "Host(``)",
+			expectedError: true,
+		},
+		{
+			desc:          "PathPrefix empty",
+			rule:          "PathPrefix(``)",
+			expectedError: true,
+		},
 		{
 			desc: "PathPrefix",
 			rule: "PathPrefix(`/foo`)",

pkg/server/router/router_test.go

@@ -62,6 +62,29 @@ func TestRouterManager_Get(t *testing.T) {
 			entryPoints: []string{"web"},
 			expected:    expectedResult{StatusCode: http.StatusOK},
 		},
+		{
+			desc: "empty host",
+			routersConfig: map[string]*dynamic.Router{
+				"foo": {
+					EntryPoints: []string{"web"},
+					Service:     "foo-service",
+					Rule:        "Host(``)",
+				},
+			},
+			serviceConfig: map[string]*dynamic.Service{
+				"foo-service": {
+					LoadBalancer: &dynamic.ServersLoadBalancer{
+						Servers: []dynamic.Server{
+							{
+								URL: server.URL,
+							},
+						},
+					},
+				},
+			},
+			entryPoints: []string{"web"},
+			expected:    expectedResult{StatusCode: http.StatusNotFound},
+		},
 		{
 			desc: "no load balancer",
 			routersConfig: map[string]*dynamic.Router{