[GitHub] [apisix-ingress-controller] gxthrj commented on a change in pull request #308: feat: traffic split

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

gxthrj commented on a change in pull request #308:
URL: https://github.com/apache/apisix-ingress-controller/pull/308#discussion_r598109279



##########
File path: docs/en/latest/concepts/apisix_route.md
##########
@@ -139,12 +139,46 @@ spec:
           - /*
         methods:
           - GET
-      backend:
-        serviceName: foo
-        servicePort: 80
-        resolveGranularity: service
+      backends:
+        - serviceName: foo
+          servicePort: 80
+          resolveGranularity: service
 ```
 
+Weight Based Traffic Split
+--------------------------
+
+There can more than one backend specified in one route rule,
+when multiple backends co-exist there, the traffic split based on weights
+will be applied (which actually uses the [traffic-split](http://apisix.apache.org/docs/apisix/plugins/traffic-split/) plugin in Apache APISIX).
+You can specify weight for each backend, the default weight is `100`.
+
+```yaml
+apiVersion: apisix.apache.org/v2alpha1
+kind: ApisixRoute
+metadata:
+  name: method-route
+spec:
+  http:
+    - name: method
+      match:
+        paths:
+          - /*
+        methods:
+          - GET
+      backends:
+        - serviceName: foo
+          servicePort: 80
+          weight: 100
+        - serviceName: bar
+          servicePort: 81
+          weight: 50
+```
+
+The above `ApisixRoute` has one route rule, which contains two backends `foo` and `bar`, the
+weight ratio is `100:50`, which means `2/3` requests will be sent to service `foo` and `1/3` requests
+will be proxied to serivce `bar`.
+

Review comment:
       Need example to show `match` with `vars`.

##########
File path: pkg/kube/translation/util.go
##########
@@ -0,0 +1,86 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You 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 translation
+
+import (
+	"errors"
+
+	"go.uber.org/zap"
+	"k8s.io/apimachinery/pkg/util/intstr"
+
+	"github.com/apache/apisix-ingress-controller/pkg/id"
+	configv2alpha1 "github.com/apache/apisix-ingress-controller/pkg/kube/apisix/apis/config/v2alpha1"
+	"github.com/apache/apisix-ingress-controller/pkg/log"
+	apisixv1 "github.com/apache/apisix-ingress-controller/pkg/types/apisix/v1"
+)
+
+func (t *translator) getServiceClusterIPAndPort(backend *configv2alpha1.ApisixRouteHTTPBackend, ar *configv2alpha1.ApisixRoute) (string, int32, error) {
+	svc, err := t.ServiceLister.Services(ar.Namespace).Get(backend.ServiceName)
+	if err != nil {
+		return "", 0, err
+	}
+	svcPort := int32(-1)
+loop:
+	for _, port := range svc.Spec.Ports {
+		switch backend.ServicePort.Type {
+		case intstr.Int:
+			if backend.ServicePort.IntVal == port.Port {
+				svcPort = port.Port
+				break loop
+			}
+		case intstr.String:
+			if backend.ServicePort.StrVal == port.Name {
+				svcPort = port.Port
+				break loop
+			}
+		}
+	}
+	if svcPort == -1 {
+		log.Errorw("ApisixRoute refers to non-existent Service port",
+			zap.Any("ApisixRoute", ar),
+			zap.String("port", backend.ServicePort.String()),
+		)
+		return "", 0, err
+	}
+
+	if backend.ResolveGranularity == "service" && svc.Spec.ClusterIP == "" {
+		log.Errorw("ApisixRoute refers to a headless service but want to use the service level resolve granularity",
+			zap.Any("ApisixRoute", ar),
+			zap.Any("service", svc),
+		)
+		return "", 0, errors.New("conflict headless service and backend resolve granularity")
+	}
+	return svc.Spec.ClusterIP, svcPort, nil
+}
+
+func (t *translator) translateUpstream(namespace, svcName, svcResolveGranularity, svcClusterIP string, svcPort int32) (*apisixv1.Upstream, error) {
+	ups, err := t.TranslateUpstream(namespace, svcName, svcPort)
+	if err != nil {
+		return nil, err
+	}
+	if svcResolveGranularity == "service" {
+		ups.Nodes = []apisixv1.UpstreamNode{
+			{
+				IP:     svcClusterIP,
+				Port:   int(svcPort),
+				Weight: _defaultWeight,
+			},
+		}
+	}
+	ups.FullName = apisixv1.ComposeUpstreamName(namespace, svcName, svcPort)
+	ups.Name = ups.FullName
+	ups.ID = id.GenID(ups.FullName)

Review comment:
       If upstream.ID is nil, what is the behavior of the controller ?

##########
File path: pkg/kube/translation/apisix_route.go
##########
@@ -108,40 +108,29 @@ func (t *translator) TranslateRouteV2alpha1(ar *configv2alpha1.ApisixRoute) ([]*
 		if len(part.Match.Paths) < 1 {
 			return nil, nil, errors.New("empty route paths match")
 		}
-		svc, err := t.ServiceLister.Services(ar.Namespace).Get(part.Backend.ServiceName)
-		if err != nil {
-			return nil, nil, err
+		if part.Backend != nil && len(part.Backends) > 1 {
+			return nil, nil, errors.New("backend and backends are exclusive")
 		}
-		svcPort := int32(-1)
-	loop:
-		for _, port := range svc.Spec.Ports {
-			switch part.Backend.ServicePort.Type {
-			case intstr.Int:
-				if part.Backend.ServicePort.IntVal == port.Port {
-					svcPort = port.Port
-					break loop
-				}
-			case intstr.String:
-				if part.Backend.ServicePort.StrVal == port.Name {
-					svcPort = port.Port
-					break loop
-				}
-			}
-		}
-		if svcPort == -1 {
-			log.Errorw("ApisixRoute refers to non-existent Service port",
-				zap.Any("ApisixRoute", ar),
-				zap.String("port", part.Backend.ServicePort.String()),
-			)
-			return nil, nil, err
+		if part.Backend == nil && len(part.Backends) == 0 {
+			return nil, nil, errors.New("no specified backend")
 		}
+		backends := part.Backends
+		backend := part.Backend
+		if len(backends) > 0 {
+			// Use the first backend as the default backend in Route,
+			// others will be configured in traffic-split plugin.
+			backend = backends[0]

Review comment:
       Confused here, `backend ` will be covered if backends is not empty ?




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