增加第一个简版的轮询负载均衡

balance/poll.go

@@ -0,0 +1,76 @@
+// Package balance ...
+//
+// Description : 轮询机制的负载均衡
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 2021-10-19 12:35 下午
+package balance
+
+import (
+	"sync"
+
+	"git.zhangdeman.cn/zhangdeman/gopkg/balance/define"
+	"github.com/pkg/errors"
+)
+
+// NewPoll 获取轮询实例
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 12:40 下午 2021/10/19
+func NewPoll(serverList []*define.ServerNode) (*Poll, error) {
+	if nil == serverList || len(serverList) == 0 {
+		return nil, errors.New("server list is empty")
+	}
+	return &Poll{
+		base: base{
+			lock: &sync.RWMutex{},
+		},
+		serverList:         serverList,
+		currentServerIndex: 0,
+	}, nil
+}
+
+// Poll ...
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 12:41 下午 2021/10/19
+type Poll struct {
+	base
+	serverList         []*define.ServerNode
+	currentServerIndex int
+}
+
+// GetServerNode 获取服务节点
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 12:43 下午 2021/10/19
+func (p *Poll) GetServerNode() (*define.ServerNode, error) {
+	if len(p.serverList) == 0 {
+		return nil, errors.New("server list is empty")
+	}
+	p.Lock()
+	defer p.Unlock()
+	var (
+		serverNode *define.ServerNode
+	)
+	// 循环次数
+	loopTimes := 0
+	for loopTimes < len(p.serverList) {
+		loopTimes++
+		p.currentServerIndex = (p.currentServerIndex + 1) % len(p.serverList)
+		if serverNode = p.serverList[p.currentServerIndex]; serverNode.Status != define.ServerNodeStatusNormal {
+			continue
+		}
+		break
+	}
+
+	if nil == serverNode || serverNode.Status != define.ServerNodeStatusNormal {
+		return nil, errors.New("has no server node be used")
+	}
+
+	return serverNode, nil
+}