udpate topicmapper policy route from map to array to eliminate random…

… order (easegress-io#622)

pkg/filters/topicmapper/topic.go

@@ -27,17 +27,22 @@ import (
 
 type topicMapFunc func(mqttTopic string) (topic string, headers map[string]string, err error)
 
-func getPolicyRoute(routes []*PolicyRe) map[string]*regexp.Regexp {
- ans := make(map[string]*regexp.Regexp)
+type policyRe struct {
+ name string
+ re *regexp.Regexp
+}
+
+func getPolicyRoute(routes []*PolicyRe) []*policyRe {
+ res := make([]*policyRe, 0, len(routes))
  for _, route := range routes {
  r, err := regexp.Compile(route.MatchExpr)
  if err != nil {
  logger.SpanErrorf(nil, "topicMapper policy <%s> match expr <%s> compile failed: %v", route.Name, route.MatchExpr, err)
  } else {
- ans[route.Name] = r
+ res = append(res, &policyRe{name: route.Name, re: r})
  }
  }
- return ans
+ return res
 }
 
 type topicRouteType map[string][]*regexp.Regexp
@@ -77,9 +82,9 @@ func getTopicMapFunc(topicMapper *Spec) topicMapFunc {
  }
 
  getPolicy := func(level string) *Policy {
- for name, r := range policyRoute {
- if r.MatchString(level) {
- return policyMap[name]
+ for _, route := range policyRoute {
+ if route.re.MatchString(level) {
+ return policyMap[route.name]
  }
  }
  return nil