115 lines
2.4 KiB
Go
115 lines
2.4 KiB
Go
package etcd
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import (
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"context"
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"net"
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"strconv"
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"time"
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clientV3 "go.etcd.io/etcd/client/v3"
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)
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type Client struct {
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v3 *clientV3.Client
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lease *clientV3.LeaseGrantResponse
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interval int32
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serviceName string
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}
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func NewClient(endpoint []string) (*Client, error) {
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client, err := clientV3.New(clientV3.Config{
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Endpoints: endpoint,
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DialTimeout: 5 * time.Second,
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})
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if err != nil {
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return nil, err
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}
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return &Client{v3: client, interval: 5}, nil
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}
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// Close 关闭client
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func (e *Client) Close() error {
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return e.v3.Close()
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}
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// Register 注册服务
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func (e *Client) Register(serviceName string, serviceAddress string) error {
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var err error
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ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
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defer cancel()
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e.lease, err = e.v3.Grant(ctx, int64(e.interval+1))
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if err != nil {
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return err
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}
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e.serviceName = serviceName + "/" + strconv.Itoa(int(e.lease.ID))
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_, err = e.v3.Put(ctx, e.serviceName, getValue(serviceAddress), clientV3.WithLease(e.lease.ID))
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if err != nil {
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return err
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}
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e.keepAlive(serviceName, serviceAddress)
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return nil
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}
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// Deregister 注销服务
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func (e *Client) Deregister() error {
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ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
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defer cancel()
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_, err := e.v3.Delete(ctx, e.serviceName)
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if err != nil {
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return err
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}
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return nil
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}
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// keepAlive 异步续约
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func (e *Client) keepAlive(name string, addr string) {
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// 永久续约，续约成功后，etcd客户端和服务器会保持通讯，通讯成功会写数据到返回的通道中
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// 停止进程后，服务器链接不上客户端，相应key租约到期会被服务器自动删除
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c, err := e.v3.KeepAlive(e.v3.Ctx(), e.lease.ID)
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go func() {
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if err == nil {
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for {
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select {
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case _, ok := <-c:
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if !ok { //续约失败
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e.v3.Revoke(e.v3.Ctx(), e.lease.ID)
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e.Register(name, addr)
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return
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}
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}
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}
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defer e.v3.Revoke(e.v3.Ctx(), e.lease.ID)
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}
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}()
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}
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// getValue etcd服务发现时，底层解析的是一个json串，且包含Addr字段
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func getValue(addr string) string {
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// return "{\"Addr\":\"" + localIP() + addr + "\"}"
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return localIP() + addr
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}
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// localIP 获取当前ip
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func localIP() string {
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addrList, err := net.InterfaceAddrs()
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if err != nil {
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return ""
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}
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for _, address := range addrList {
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if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
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if ipnet.IP.To4() != nil {
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return ipnet.IP.String()
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}
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}
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}
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return ""
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}
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