add router chain

cluster/router/condition/router.go

@@ -45,7 +45,7 @@ const (
 )
 
 var (
-	routerPatternReg = regexp.MustCompile(ROUTE_PATTERN)
+	routerPatternReg = regexp.MustCompile(`([&!=,]*)\s*([^&!=,\s]+)`)
 )
 
 //ConditionRouter condition router struct

registry/directory/directory_test.go

@@ -33,6 +33,7 @@ import (
 import (
 	"github.com/apache/dubbo-go/cluster/cluster_impl"
 	_ "github.com/apache/dubbo-go/cluster/router"
+	_ "github.com/apache/dubbo-go/cluster/router/condition"
 	"github.com/apache/dubbo-go/common"
 	"github.com/apache/dubbo-go/common/constant"
 	"github.com/apache/dubbo-go/common/extension"