backport: part 5

api/adc/types.go

@@ -505,6 +505,20 @@ func (n *UpstreamNodes) UnmarshalJSON(p []byte) error {
 	return nil
 }
 
+// MarshalJSON implements the json.Marshaler interface for UpstreamNodes.
+// By default, Go serializes a nil slice as JSON null. However, for compatibility
+// with APISIX semantics, we want a nil UpstreamNodes to be encoded as an empty
+// array ([]) instead of null. Non-nil slices are marshaled as usual.
+//
+// See APISIX upstream nodes schema definition for details:
+// https://github.com/apache/apisix/blob/77dacda31277a31d6014b4970e36bae2a5c30907/apisix/schema_def.lua#L295-L338
+func (n UpstreamNodes) MarshalJSON() ([]byte, error) {
+	if n == nil {
+		return []byte("[]"), nil
+	}
+	return json.Marshal([]UpstreamNode(n))
+}
+
 // ComposeRouteName uses namespace, name and rule name to compose
 // the route name.
 func ComposeRouteName(namespace, name string, rule string) string {
@@ -621,9 +635,9 @@ type ResponseRewriteConfig struct {
 }
 
 type ResponseHeaders struct {
-	Set    map[string]string `json:"set" yaml:"set"`
-	Add    []string          `json:"add" yaml:"add"`
-	Remove []string          `json:"remove" yaml:"remove"`
+	Set    map[string]string `json:"set,omitempty" yaml:"set,omitempty"`
+	Add    []string          `json:"add,omitempty" yaml:"add,omitempty"`
+	Remove []string          `json:"remove,omitempty" yaml:"remove,omitempty"`
 }
 
 // RequestMirror is the rule config for proxy-mirror plugin.

internal/adc/translator/httproute.go

@@ -33,6 +33,7 @@ import (
 
 	adctypes "github.com/apache/apisix-ingress-controller/api/adc"
 	"github.com/apache/apisix-ingress-controller/api/v1alpha1"
+	apiv2 "github.com/apache/apisix-ingress-controller/api/v2"
 	"github.com/apache/apisix-ingress-controller/internal/controller/label"
 	"github.com/apache/apisix-ingress-controller/internal/id"
 	"github.com/apache/apisix-ingress-controller/internal/provider"
@@ -285,7 +286,7 @@ func (t *Translator) fillHTTPRoutePolicies(routes []*adctypes.Route, policies []
 }
 
 func (t *Translator) translateEndpointSlice(portName *string, weight int, endpointSlices []discoveryv1.EndpointSlice, endpointFilter func(*discoveryv1.Endpoint) bool) adctypes.UpstreamNodes {
-	var nodes adctypes.UpstreamNodes
+	nodes := adctypes.UpstreamNodes{}
 	if len(endpointSlices) == 0 {
 		return nodes
 	}
@@ -466,32 +467,89 @@ func (t *Translator) TranslateHTTPRoute(tctx *provider.TranslateContext, httpRou
 	labels := label.GenLabel(httpRoute)
 
 	for ruleIndex, rule := range rules {
-		upstream := adctypes.NewDefaultUpstream()
-		var backendErr error
+		service := adctypes.NewDefaultService()
+		service.Labels = labels
+
+		service.Name = adctypes.ComposeServiceNameWithRule(httpRoute.Namespace, httpRoute.Name, fmt.Sprintf("%d", ruleIndex))
+		service.ID = id.GenID(service.Name)
+		service.Hosts = hosts
+
+		var (
+			upstreams         = make([]*adctypes.Upstream, 0)
+			weightedUpstreams = make([]adctypes.TrafficSplitConfigRuleWeightedUpstream, 0)
+			backendErr        error
+		)
+
 		for _, backend := range rule.BackendRefs {
 			if backend.Namespace == nil {
 				namespace := gatewayv1.Namespace(httpRoute.Namespace)
 				backend.Namespace = &namespace
 			}
+			upstream := adctypes.NewDefaultUpstream()
 			upNodes, err := t.translateBackendRef(tctx, backend.BackendRef, DefaultEndpointFilter)
 			if err != nil {
 				backendErr = err
 				continue
 			}
+			if len(upNodes) == 0 {
+				continue
+			}
+
 			t.AttachBackendTrafficPolicyToUpstream(backend.BackendRef, tctx.BackendTrafficPolicies, upstream)
-			upstream.Nodes = append(upstream.Nodes, upNodes...)
+			upstream.Nodes = upNodes
+			upstreams = append(upstreams, upstream)
 		}
 
-		// todo: support multiple backends
-		service := adctypes.NewDefaultService()
-		service.Labels = labels
+		// Handle multiple backends with traffic-split plugin
+		if len(upstreams) == 0 {
+			// Create a default upstream if no valid backends
+			upstream := adctypes.NewDefaultUpstream()
+			service.Upstream = upstream
+		} else if len(upstreams) == 1 {
+			// Single backend - use directly as service upstream
+			service.Upstream = upstreams[0]
+		} else {
+			// Multiple backends - use traffic-split plugin
+			service.Upstream = upstreams[0]
+			upstreams = upstreams[1:]
+
+			// Set weight in traffic-split for the default upstream
+			weight := apiv2.DefaultWeight
+			if rule.BackendRefs[0].Weight != nil {
+				weight = int(*rule.BackendRefs[0].Weight)
+			}
+			weightedUpstreams = append(weightedUpstreams, adctypes.TrafficSplitConfigRuleWeightedUpstream{
+				Weight: weight,
+			})
 
-		service.Name = adctypes.ComposeServiceNameWithRule(httpRoute.Namespace, httpRoute.Name, fmt.Sprintf("%d", ruleIndex))
-		service.ID = id.GenID(service.Name)
-		service.Hosts = hosts
-		service.Upstream = upstream
+			// Set other upstreams in traffic-split
+			for i, upstream := range upstreams {
+				weight := apiv2.DefaultWeight
+				// get weight from the backend refs starting from the second backend
+				if i+1 < len(rule.BackendRefs) && rule.BackendRefs[i+1].Weight != nil {
+					weight = int(*rule.BackendRefs[i+1].Weight)
+				}
+				weightedUpstreams = append(weightedUpstreams, adctypes.TrafficSplitConfigRuleWeightedUpstream{
+					Upstream: upstream,
+					Weight:   weight,
+				})
+			}
+
+			if len(weightedUpstreams) > 0 {
+				if service.Plugins == nil {
+					service.Plugins = make(map[string]any)
+				}
+				service.Plugins["traffic-split"] = &adctypes.TrafficSplitConfig{
+					Rules: []adctypes.TrafficSplitConfigRule{
+						{
+							WeightedUpstreams: weightedUpstreams,
+						},
+					},
+				}
+			}
+		}
 
-		if backendErr != nil && len(upstream.Nodes) == 0 {
+		if backendErr != nil && (service.Upstream == nil || len(service.Upstream.Nodes) == 0) {
 			if service.Plugins == nil {
 				service.Plugins = make(map[string]any)
 			}

internal/adc/translator/ingress.go

@@ -222,7 +222,7 @@ func (t *Translator) TranslateIngress(tctx *provider.TranslateContext, obj *netw
 
 // translateEndpointSliceForIngress create upstream nodes from EndpointSlice
 func (t *Translator) translateEndpointSliceForIngress(weight int, endpointSlices []discoveryv1.EndpointSlice, servicePort *corev1.ServicePort) adctypes.UpstreamNodes {
-	var nodes adctypes.UpstreamNodes
+	nodes := adctypes.UpstreamNodes{}
 	if len(endpointSlices) == 0 {
 		return nodes
 	}

internal/provider/apisix/provider.go

@@ -38,12 +38,20 @@ import (
 	"github.com/apache/apisix-ingress-controller/internal/controller/status"
 	"github.com/apache/apisix-ingress-controller/internal/manager/readiness"
 	"github.com/apache/apisix-ingress-controller/internal/provider"
+	"github.com/apache/apisix-ingress-controller/internal/provider/common"
 	"github.com/apache/apisix-ingress-controller/internal/types"
 	"github.com/apache/apisix-ingress-controller/internal/utils"
 	pkgutils "github.com/apache/apisix-ingress-controller/pkg/utils"
 )
 
-const ProviderTypeAPISIX = "apisix"
+const (
+	ProviderTypeAPISIX = "apisix"
+
+	RetryBaseDelay = 1 * time.Second
+	RetryMaxDelay  = 1000 * time.Second
+
+	MinSyncPeriod = 1 * time.Second
+)
 
 type apisixProvider struct {
 	provider.Options
@@ -229,33 +237,32 @@ func (d *apisixProvider) Start(ctx context.Context) error {
 
 	initalSyncDelay := d.InitSyncDelay
 	if initalSyncDelay > 0 {
-		time.AfterFunc(initalSyncDelay, func() {
-			if err := d.sync(ctx); err != nil {
-				log.Error(err)
-				return
-			}
-		})
+		time.AfterFunc(initalSyncDelay, d.syncNotify)
 	}
 
-	if d.SyncPeriod < 1 {
-		return nil
+	syncPeriod := d.SyncPeriod
+	if syncPeriod < MinSyncPeriod {
+		syncPeriod = MinSyncPeriod
 	}
-	ticker := time.NewTicker(d.SyncPeriod)
+	ticker := time.NewTicker(syncPeriod)
 	defer ticker.Stop()
+
+	retrier := common.NewRetrier(common.NewExponentialBackoff(RetryBaseDelay, RetryMaxDelay))
+
 	for {
-		synced := false
 		select {
 		case <-d.syncCh:
-			synced = true
 		case <-ticker.C:
-			synced = true
+		case <-retrier.C():
 		case <-ctx.Done():
+			retrier.Reset()
 			return nil
 		}
-		if synced {
-			if err := d.sync(ctx); err != nil {
-				log.Error(err)
-			}
+		if err := d.sync(ctx); err != nil {
+			log.Error(err)
+			retrier.Next()
+		} else {
+			retrier.Reset()
 		}
 	}
 }

internal/provider/common/retrier.go

@@ -0,0 +1,96 @@
+// 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 common
+
+import (
+	"sync"
+	"time"
+)
+
+type Backoff interface {
+	Next() time.Duration
+	Reset()
+}
+
+type ExponentialBackoff struct {
+	base, max, current time.Duration
+}
+
+func NewExponentialBackoff(base, max time.Duration) *ExponentialBackoff {
+	return &ExponentialBackoff{base: base, max: max, current: base}
+}
+
+func (b *ExponentialBackoff) Next() time.Duration {
+	delay := b.current
+	b.current *= 2
+	if b.current > b.max {
+		b.current = b.max
+	}
+	return delay
+}
+
+func (b *ExponentialBackoff) Reset() {
+	b.current = b.base
+}
+
+type Retrier struct {
+	mu      sync.Mutex
+	ch      chan struct{}
+	timer   *time.Timer
+	backoff Backoff
+}
+
+func NewRetrier(b Backoff) *Retrier {
+	return &Retrier{
+		ch:      make(chan struct{}, 1),
+		backoff: b,
+	}
+}
+
+func (r *Retrier) Reset() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if r.timer != nil {
+		r.timer.Stop()
+		r.timer = nil
+	}
+	r.backoff.Reset()
+}
+
+func (r *Retrier) Next() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if r.timer != nil {
+		r.timer.Stop()
+		r.timer = nil
+	}
+
+	delay := r.backoff.Next()
+	r.timer = time.AfterFunc(delay, func() {
+		select {
+		case r.ch <- struct{}{}:
+		default:
+		}
+	})
+}
+
+func (r *Retrier) C() <-chan struct{} {
+	return r.ch
+}