/
weight_round_robin_selector.go
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/
weight_round_robin_selector.go
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// 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 selector
import (
"errors"
"github.com/apache/eventmesh/eventmesh-sdk-go/http/conf"
"go.uber.org/atomic"
)
const WeightRoundRobinSelectorType = "weight_round_robin"
func init() {
registerSelectorBuilder(WeightRoundRobinSelectorType, buildWeightRoundRobinLoadSelector)
}
func buildWeightRoundRobinLoadSelector(config *conf.EventMeshHttpClientConfig) (LoadBalanceSelector, error) {
meshNodes, err := parseWeightedMeshNodeFromConfig(config)
if err != nil {
return nil, err
}
return NewWeightRoundRobinLoadSelector(meshNodes)
}
type WeightRoundRobinMeshNode struct {
MeshNode
currentWeight *atomic.Int64
}
type WeightRoundRobinLoadSelector struct {
clusterGroup []WeightRoundRobinMeshNode
totalWeight int64
}
func NewWeightRoundRobinLoadSelector(clusterGroup []MeshNode) (*WeightRoundRobinLoadSelector, error) {
if len(clusterGroup) == 0 {
return nil, errors.New("fail to create weight round robin load balancer selector, cluster group is empty")
}
var totalWeight int64 = 0
weightRoundRobinClusterGroup := make([]WeightRoundRobinMeshNode, 0, len(clusterGroup))
for _, node := range clusterGroup {
totalWeight += node.Weight
weightRoundRobinClusterGroup = append(weightRoundRobinClusterGroup, WeightRoundRobinMeshNode{
MeshNode: node,
currentWeight: atomic.NewInt64(0),
})
}
return &WeightRoundRobinLoadSelector{
clusterGroup: weightRoundRobinClusterGroup,
totalWeight: totalWeight,
}, nil
}
func (s *WeightRoundRobinLoadSelector) Select() MeshNode {
var targetWeight *WeightRoundRobinMeshNode = nil
for i := range s.clusterGroup {
node := &s.clusterGroup[i]
node.currentWeight.Add(node.Weight)
if targetWeight == nil || targetWeight.currentWeight.Load() < node.currentWeight.Load() {
targetWeight = node
}
}
targetWeight.currentWeight.Sub(s.totalWeight)
return targetWeight.MeshNode
}
func (s *WeightRoundRobinLoadSelector) GetType() string {
return WeightRoundRobinSelectorType
}