feat: 增加balancerFilter优先匹配

[tyouzu1]

https://github.com/sofastack/sofa-rpc-node/issues/96

在使用registry的情况下，如果有较多的地址，在这里希望能够进行部分地址增加优先级优先掉用

我的需求： 如地址1、2、3 、4、5、6。希望能够先掉用 1、2、3，并且兜底不可用情况，重新走之前的逻辑 随机掉用1-6

所以在此增加一个balancerFilter，在_loadbalancer.select之前先掉用一次，筛选出需要优先掉用的地址，优先连接一次。不可用时使用原逻辑。

例子

const { RpcClient } = require('sofa-rpc-node').client;
const { ZookeeperRegistry } = require('sofa-rpc-node').registry;
const logger = console;

// 1. 创建 zk 注册中心客户端
const registry = new ZookeeperRegistry({
  logger,
  address: '127.0.0.1:2181',
});

async function invoke() {
  // 2. 创建 RPC Client 实例
  const client = new RpcClient({
    logger,
    registry,
  });
  // 3. 创建服务的 consumer
  const consumer = client.createConsumer({
    interfaceName: 'com.nodejs.test.TestService',
    balancerFilter: addressList => {
        // 可以重写addressList,进行filter可以实现优先级功能
        // 如: 优先匹配`host === '127.0.0.1:13202'`的地址
        return addressList.filter(v => v.host === '127.0.0.1:13202');
    },
  });
  // 4. 等待 consumer ready（从注册中心订阅服务列表...）
  await consumer.ready();

  // 5. 执行泛化调用
  const result = await consumer.invoke('plus', [ 1, 2 ], { responseTimeout: 3000 });
  console.log('1 + 2 = ' + result);
}

invoke().catch(console.error);

[tyouzu1]

@fengmk2 麻烦帮忙看一下啦，谢谢

[codecov[bot]]

Codecov Report

Merging #97 (55d857d) into master (1921e7d) will increase coverage by 0.02%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #97      +/-   ##
==========================================
+ Coverage   98.31%   98.33%   +0.02%     
==========================================
  Files          38       38              
  Lines        2311     2344      +33     
  Branches      367      378      +11     
==========================================
+ Hits         2272     2305      +33     
  Misses         39       39              

Impacted Files	Coverage Δ
lib/client/address_group.js	99.13% <100.00%> (+0.03%)	:arrow_up:
lib/client/loadbalancer/base.js	97.80% <100.00%> (+0.24%)	:arrow_up:
lib/client/loadbalancer/weight_rr.js	100.00% <100.00%> (ø)

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[tyouzu1]

@fengmk2 老哥这个还有合进去的可能么

[tyouzu1]

@fengmk2 老哥这个还有合进去的可能么

如果可以的话，或者简单点这样，https://github.com/sofastack/sofa-rpc-node/pull/100 把createLoadBalancer增加到参数里。把createLoadBalancer透出也方便去定制功能

const defaultOptions = {
  loadbalancerClass: 'roundRobin',
  retryFaultInterval: 30000, // 30s 重新尝试连接下不可用的地址
  waitConnect: true,
  createLoadBalancer,
};
class AddressGroup extends Base {
  constructor(options = {}) {
    ...
    this._loadbalancer = options.createLoadBalancer(this);