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170 lines
4.3 KiB
170 lines
4.3 KiB
package clientPkg
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import (
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"math/rand"
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"simple-kv-store/internal/logprovider"
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"simple-kv-store/internal/nodes"
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"time"
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"go.uber.org/zap"
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)
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var log, _ = logprovider.CreateDefaultZapLogger(zap.InfoLevel)
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type Client struct {
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ClientId string // 每个client唯一标识
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NextLogId int
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// 连接的server端节点群
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PeerIds []string
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Transport nodes.Transport
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}
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type Status = uint8
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const (
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Ok Status = iota + 1
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NotFound
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Fail
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)
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func NewClient(clientId string, peerIds []string, transport nodes.Transport) *Client {
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return &Client{ClientId: clientId, NextLogId: 0, PeerIds: peerIds, Transport: transport}
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}
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func getRandomAddress(peerIds []string) string {
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// 随机选一个 id
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randomKey := peerIds[rand.Intn(len(peerIds))]
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return randomKey
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}
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func (client *Client) FindActiveNode() nodes.ClientInterface {
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var err error
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var c nodes.ClientInterface
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for { // 直到找到一个可连接的节点（保证至少一个节点活着）
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peerId := getRandomAddress(client.PeerIds)
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c, err = client.Transport.DialHTTPWithTimeout("tcp", "", peerId)
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if err != nil {
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log.Error("dialing: ", zap.Error(err))
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} else {
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log.Sugar().Infof("client发现活跃节点[%s]", peerId)
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return c
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}
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}
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}
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func (client *Client) CloseRpcClient(c nodes.ClientInterface) {
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err := c.Close()
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if err != nil {
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log.Error("client close err: ", zap.Error(err))
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}
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}
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func (client *Client) Write(kv nodes.LogEntry) Status {
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defer logprovider.DebugTraceback("client")
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log.Info("client write request key :" + kv.Key)
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kvCall := nodes.LogEntryCall{LogE: kv,
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Id: nodes.LogEntryCallId{ClientId: client.ClientId, LogId: client.NextLogId}}
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client.NextLogId++
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c := client.FindActiveNode()
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var err error
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timeout := time.Second
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deadline := time.Now().Add(timeout)
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for { // 根据存活节点的反馈，直到找到leader
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if time.Now().After(deadline) {
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log.Error("系统繁忙，疑似出错")
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return Fail
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}
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var reply nodes.ServerReply
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reply.Isleader = false
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callErr := client.Transport.CallWithTimeout(c, "Node.WriteKV", &kvCall, &reply) // RPC
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if callErr != nil { // dial和call之间可能崩溃，重新找存活节点
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log.Error("dialing: ", zap.Error(callErr))
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client.CloseRpcClient(c)
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c = client.FindActiveNode()
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continue
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}
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if !reply.Isleader { // 对方不是leader，根据反馈找leader
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leaderId := reply.LeaderId
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client.CloseRpcClient(c)
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if leaderId == "" { // 这个节点不知道leader是谁，再随机找
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c = client.FindActiveNode()
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} else { // dial leader
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c, err = client.Transport.DialHTTPWithTimeout("tcp", "", leaderId)
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if err != nil { // dial失败，重新找下一个存活节点
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c = client.FindActiveNode()
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}
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}
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} else { // 成功
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client.CloseRpcClient(c)
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return Ok
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}
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}
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}
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func (client *Client) Read(key string, value *string) Status { // 查不到value为空
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log.Info("client read request key :" + key)
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if value == nil {
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return Fail
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}
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var c nodes.ClientInterface
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for {
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c = client.FindActiveNode()
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var reply nodes.ServerReply
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callErr := client.Transport.CallWithTimeout(c, "Node.ReadKey", &key, &reply) // RPC
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if callErr != nil {
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log.Error("dialing: ", zap.Error(callErr))
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client.CloseRpcClient(c)
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continue
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}
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// 目前一定发送成功
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if reply.HaveValue {
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*value = reply.Value
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client.CloseRpcClient(c)
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return Ok
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} else {
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client.CloseRpcClient(c)
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return NotFound
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}
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}
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}
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func (client *Client) FindLeader() string {
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var arg struct{}
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var reply nodes.FindLeaderReply
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reply.Isleader = false
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c := client.FindActiveNode()
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var err error
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for !reply.Isleader { // 根据存活节点的反馈，直到找到leader
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callErr := client.Transport.CallWithTimeout(c, "Node.FindLeader", &arg, &reply) // RPC
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if callErr != nil { // dial和call之间可能崩溃，重新找存活节点
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log.Error("dialing: ", zap.Error(callErr))
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client.CloseRpcClient(c)
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c = client.FindActiveNode()
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continue
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}
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if !reply.Isleader { // 对方不是leader，根据反馈找leader
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client.CloseRpcClient(c)
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c, err = client.Transport.DialHTTPWithTimeout("tcp", "", reply.LeaderId)
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for err != nil { // 重新找下一个存活节点
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c = client.FindActiveNode()
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}
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} else { // 成功
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client.CloseRpcClient(c)
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return reply.LeaderId
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}
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}
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log.Fatal("客户端会一直找存活节点，不会运行到这里")
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return "fault"
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}
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