dubbo.apache.org/dubbo-go/v3@v3.1.1/cluster/loadbalance/interleavedweightedroundrobin/loadbalance.go (about)

     1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   * contributor license agreements.  See the NOTICE file distributed with
     4   * this work for additional information regarding copyright ownership.
     5   * The ASF licenses this file to You under the Apache License, Version 2.0
     6   * (the "License"); you may not use this file except in compliance with
     7   * the License.  You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  
    18  package iwrr
    19  
    20  import (
    21  	"dubbo.apache.org/dubbo-go/v3/cluster/loadbalance"
    22  	"dubbo.apache.org/dubbo-go/v3/common/constant"
    23  	"dubbo.apache.org/dubbo-go/v3/common/extension"
    24  	"dubbo.apache.org/dubbo-go/v3/protocol"
    25  )
    26  
    27  func init() {
    28  	extension.SetLoadbalance(constant.LoadBalanceKeyInterleavedWeightedRoundRobin, newInterleavedWeightedRoundRobinBalance)
    29  }
    30  
    31  type interleavedWeightedRoundRobinBalance struct{}
    32  
    33  // newInterleavedWeightedRoundRobinBalance returns a interleaved weighted round robin load balance.
    34  func newInterleavedWeightedRoundRobinBalance() loadbalance.LoadBalance {
    35  	return &interleavedWeightedRoundRobinBalance{}
    36  }
    37  
    38  // Select gets invoker based on interleaved weighted round robine load balancing strategy
    39  func (lb *interleavedWeightedRoundRobinBalance) Select(invokers []protocol.Invoker, invocation protocol.Invocation) protocol.Invoker {
    40  	count := len(invokers)
    41  	if count == 0 {
    42  		return nil
    43  	}
    44  	if count == 1 {
    45  		return invokers[0]
    46  	}
    47  
    48  	iwrrp := NewInterleavedweightedRoundRobin(invokers, invocation)
    49  	return iwrrp.Pick(invocation)
    50  }