[GitHub] [dubbo-go] zouyx commented on a change in pull request #703: Ftr: add dynamic tag router

[GitBox <gi...@apache.org>]

zouyx commented on a change in pull request #703:
URL: https://github.com/apache/dubbo-go/pull/703#discussion_r467545829



##########
File path: cluster/router/tag/tag_router.go
##########
@@ -55,15 +64,118 @@ func (c *tagRouter) isEnabled() bool {
 	return c.enabled
 }
 
+func (c *tagRouter) tagRouterRuleCopy() RouterRule {
+	routerRule := *c.tagRouterRule
+	return routerRule
+}
+
 // Route gets a list of invoker
 func (c *tagRouter) Route(invokers []protocol.Invoker, url *common.URL, invocation protocol.Invocation) []protocol.Invoker {
-	if !c.isEnabled() {
+	var (
+		result    []protocol.Invoker
+		addresses []string
+	)
+
+	if !c.isEnabled() || len(invokers) == 0 {
 		return invokers
 	}
+
+	// Use static tags if dynamic tags are not set or invalid
+	if c.tagRouterRule == nil || !c.tagRouterRule.Valid || !c.tagRouterRule.Enabled {
+		return filterUsingStaticTag(invokers, url, invocation)
+	}
+
+	// since the rule can be changed by config center, we should copy one to use.
+	tagRouterRuleCopy := c.tagRouterRuleCopy()
+	tag, ok := invocation.Attachments()[constant.Tagkey]
+	if !ok {
+		tag = url.GetParam(constant.Tagkey, "")
+	}
+
+	// if we are requesting for a Provider with a specific tag
+	if len(tag) > 0 {
+		return filterInvokersWithTag(invokers, url, invocation, tagRouterRuleCopy, tag)
+	}
+
+	// return all addresses in dynamic tag group.
+	addresses = tagRouterRuleCopy.getAddresses()
+	if len(addresses) > 0 {
+		filterAddressNotMatches := func(invoker protocol.Invoker) bool {
+			url := invoker.GetUrl()
+			return len(addresses) == 0 || !checkAddressMatch(addresses, url.Ip, url.Port)
+		}
+		result = filterInvoker(invokers, filterAddressNotMatches)
+		// 1. all addresses are in dynamic tag group, return empty list.
+		if len(result) == 0 {
+			return result
+		}
+	}
+	// 2. if there are some addresses that are not in any dynamic tag group, continue to filter using the
+	// static tag group.
+	filter := func(invoker protocol.Invoker) bool {
+		localTag := invoker.GetUrl().GetParam(constant.Tagkey, "")
+		return localTag == "" || !(tagRouterRuleCopy.hasTag(localTag))

Review comment:
       ```suggestion
   		return len(localTag)==0|| !(tagRouterRuleCopy.hasTag(localTag))
   ```

##########
File path: cluster/router/router.go
##########
@@ -50,3 +50,14 @@ type PriorityRouter interface {
 	// 0 to ^int(0) is better
 	Priority() int64
 }
+
+// NotifyRouter notify router use the invoker list. Invoker list may change from time to time. This method gives the router a
+// chance to prepare before {@link Router#route(List, URL, Invocation)} gets called.
+type NotifyRouter interface {
+	router

Review comment:
       ```suggestion
   	PriorityRouter
   ```
   if `NotifyRouter ` is a `PriorityRouter` , you just extends `PriorityRouter` not router.




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