Support nacos discovery (#108)

pkg/ingress/kube/annotations/annotations.go

@@ -61,6 +61,8 @@ type Ingress struct {
 	Fallback *FallbackConfig
 
 	Auth *AuthConfig
+
+	Destination *DestinationConfig
 }
 
 func (i *Ingress) NeedRegexMatch() bool {
@@ -129,6 +131,7 @@ func NewAnnotationHandlerManager() AnnotationHandler {
 			loadBalance{},
 			fallback{},
 			auth{},
+			destination{},
 		},
 		gatewayHandlers: []GatewayHandler{
 			downstreamTLS{},

pkg/ingress/kube/annotations/destination.go

@@ -0,0 +1,122 @@
+// Copyright (c) 2022 Alibaba Group Holding Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package annotations
+
+import (
+	"bufio"
+	"strconv"
+	"strings"
+
+	networking "istio.io/api/networking/v1alpha3"
+
+	. "github.com/alibaba/higress/pkg/ingress/log"
+)
+
+const (
+	destinationKey = "destination"
+)
+
+var _ Parser = destination{}
+
+type DestinationConfig struct {
+	McpDestination []*networking.HTTPRouteDestination
+}
+
+type destination struct{}
+
+func (a destination) Parse(annotations Annotations, config *Ingress, globalContext *GlobalContext) error {
+	if !needDestinationConfig(annotations) {
+		return nil
+	}
+	value, err := annotations.ParseStringForHigress(destinationKey)
+	if err != nil {
+		IngressLog.Errorf("parse destination error %v within ingress %s/%s", err, config.Namespace, config.Name)
+		return nil
+	}
+	lines := splitLines(value)
+	var destinations []*networking.HTTPRouteDestination
+	var weightSum int64
+	for _, line := range lines {
+		// fmt: [weight] <host>[:port] [subset]
+		// example: 100% my-svc.DEFAULT-GROUP.xxxx.nacos:8080 v1
+		pairs := strings.Fields(line)
+		var weight int64 = 100
+		var addrIndex int
+		if strings.HasSuffix(pairs[0], "%") {
+			weight, err = strconv.ParseInt(strings.TrimSuffix(pairs[0], "%"), 10, 32)
+			if err != nil {
+				IngressLog.Errorf("parse destination atoi error %v within ingress %s/%s", err, config.Namespace, config.Name)
+				return nil
+			}
+			addrIndex++
+		}
+		weightSum += weight
+		if len(pairs) < addrIndex+1 {
+			IngressLog.Errorf("destination %s has no address within ingress %s/%s", value, config.Namespace, config.Name)
+			return nil
+		}
+		address := pairs[addrIndex]
+		host := address
+		var port string
+		colon := strings.LastIndex(address, ":")
+		if colon != -1 {
+			host, port = address[:colon], address[colon+1:]
+		}
+		var subset string
+		if len(pairs) >= addrIndex+2 {
+			subset = pairs[addrIndex+1]
+		}
+		dest := &networking.HTTPRouteDestination{
+			Destination: &networking.Destination{
+				Host:   host,
+				Subset: subset,
+			},
+			Weight: int32(weight),
+		}
+		if port != "" {
+			portNumber, err := strconv.ParseUint(port, 10, 32)
+			if err != nil {
+				IngressLog.Errorf("destination addr %s has invalid port %s within ingress %s/%s", address, port, config.Namespace, config.Name)
+				return nil
+			}
+			dest.Destination.Port = &networking.PortSelector{
+				Number: uint32(portNumber),
+			}
+		}
+		IngressLog.Debugf("destination generated for ingress %s/%s: %v", config.Namespace, config.Name, dest)
+		destinations = append(destinations, dest)
+	}
+	if weightSum != 100 {
+		IngressLog.Errorf("destination has invalid weight sum %d within ingress %s/%s", weightSum, config.Namespace, config.Name)
+		return nil
+	}
+	config.Destination = &DestinationConfig{
+		McpDestination: destinations,
+	}
+	return nil
+}
+
+func needDestinationConfig(annotations Annotations) bool {
+	return annotations.HasHigress(destinationKey)
+}
+
+func splitLines(s string) []string {
+	var lines []string
+	sc := bufio.NewScanner(strings.NewReader(s))
+	for sc.Scan() {
+		lines = append(lines, sc.Text())
+	}
+	return lines
+}