增加轮询负载均衡

[twomiao]

hi，你好

GatewayWorker 负载均衡模式随机性分配，导致每个worker 服务连接负载不均匀，有的进程连接数比较少，有的连接数比较多。 所以扩展了一下轮询负载均衡，Nginx 默认也是轮询负载均衡。

测试代码： 并发连接数 5000，测试负载均衡是否均匀。

增加负载均衡模式两种：随机，轮询（已更改为默认）

// 设置轮询 Gateway::$selectLoadBalancingMode = Gateway::ROUTER_ROUND_ROBIN;

// 设置随机 Gateway::$selectLoadBalancingMode = Gateway::ROUTER_RANDOM;

测试负载均衡结果如下：

随机负载均衡： { "127.0.0.1:ChatBusinessWorker:28": 180, "127.0.0.1:ChatBusinessWorker:22": 160, "127.0.0.1:ChatBusinessWorker:12": 144, "127.0.0.1:ChatBusinessWorker:16": 151, "127.0.0.1:ChatBusinessWorker:31": 150, "127.0.0.1:ChatBusinessWorker:13": 146, "127.0.0.1:ChatBusinessWorker:15": 164, "127.0.0.1:ChatBusinessWorker:24": 163, "127.0.0.1:ChatBusinessWorker:25": 169, "127.0.0.1:ChatBusinessWorker:18": 157, "127.0.0.1:ChatBusinessWorker:29": 142, "127.0.0.1:ChatBusinessWorker:6": 168, "127.0.0.1:ChatBusinessWorker:3": 153, "127.0.0.1:ChatBusinessWorker:26": 148, "127.0.0.1:ChatBusinessWorker:21": 134, "127.0.0.1:ChatBusinessWorker:9": 131, "127.0.0.1:ChatBusinessWorker:27": 155, "127.0.0.1:ChatBusinessWorker:30": 173, "127.0.0.1:ChatBusinessWorker:23": 169, "127.0.0.1:ChatBusinessWorker:1": 156, "127.0.0.1:ChatBusinessWorker:4": 154, "127.0.0.1:ChatBusinessWorker:20": 156, "127.0.0.1:ChatBusinessWorker:7": 146, "127.0.0.1:ChatBusinessWorker:17": 149, "127.0.0.1:ChatBusinessWorker:10": 162, "127.0.0.1:ChatBusinessWorker:19": 163, "127.0.0.1:ChatBusinessWorker:5": 147, "127.0.0.1:ChatBusinessWorker:2": 163, "127.0.0.1:ChatBusinessWorker:8": 162, "127.0.0.1:ChatBusinessWorker:11": 164, "127.0.0.1:ChatBusinessWorker:14": 166, "127.0.0.1:ChatBusinessWorker:0": 155 }

// 可见随机的劣势，最小值131，最大值180，分配不均衡导致性能问题。

轮询负载均衡： { "127.0.0.1:ChatBusinessWorker:24": 157, "127.0.0.1:ChatBusinessWorker:13": 157, "127.0.0.1:ChatBusinessWorker:29": 157, "127.0.0.1:ChatBusinessWorker:11": 157, "127.0.0.1:ChatBusinessWorker:30": 157, "127.0.0.1:ChatBusinessWorker:20": 157, "127.0.0.1:ChatBusinessWorker:4": 157, "127.0.0.1:ChatBusinessWorker:18": 157, "127.0.0.1:ChatBusinessWorker:10": 156, "127.0.0.1:ChatBusinessWorker:0": 156, "127.0.0.1:ChatBusinessWorker:1": 156, "127.0.0.1:ChatBusinessWorker:28": 156, "127.0.0.1:ChatBusinessWorker:21": 156, "127.0.0.1:ChatBusinessWorker:2": 156, "127.0.0.1:ChatBusinessWorker:7": 156, "127.0.0.1:ChatBusinessWorker:3": 156, "127.0.0.1:ChatBusinessWorker:14": 156, "127.0.0.1:ChatBusinessWorker:19": 156, "127.0.0.1:ChatBusinessWorker:17": 156, "127.0.0.1:ChatBusinessWorker:26": 156, "127.0.0.1:ChatBusinessWorker:6": 156, "127.0.0.1:ChatBusinessWorker:22": 156, "127.0.0.1:ChatBusinessWorker:9": 156, "127.0.0.1:ChatBusinessWorker:15": 156, "127.0.0.1:ChatBusinessWorker:27": 156, "127.0.0.1:ChatBusinessWorker:16": 156, "127.0.0.1:ChatBusinessWorker:25": 156, "127.0.0.1:ChatBusinessWorker:5": 156, "127.0.0.1:ChatBusinessWorker:8": 156, "127.0.0.1:ChatBusinessWorker:12": 156, "127.0.0.1:ChatBusinessWorker:23": 156, "127.0.0.1:ChatBusinessWorker:31": 156 }

从结果来看轮询负载均衡能够好分配连接到业务逻辑服务器，不会出现某些业务服务器空闲，有些繁忙。 可自定义选择使用随机，轮询，我已经修改默认为轮询均衡分配连接给BusinessWorker服务器。

// array_search(min($roundRobinRecord), $roundRobinRecord, true); 使用最小值就是方便分布式部署新的服务器进程上线空闲，这时候连接上线初始化连接为0， Gateway根据内部轮询表判断哪台服务器连接数少就分配给谁，这样达到连接数最终均衡的目的。

[walkor]

感谢pr