package protocol
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import (
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"sync"
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)
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type ServerList struct {
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sync.RWMutex
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servers []*ServerSpec
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}
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func NewServerList() *ServerList {
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return &ServerList{}
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}
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func (sl *ServerList) AddServer(server *ServerSpec) {
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sl.Lock()
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defer sl.Unlock()
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sl.servers = append(sl.servers, server)
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}
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func (sl *ServerList) Size() uint32 {
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sl.RLock()
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defer sl.RUnlock()
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return uint32(len(sl.servers))
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}
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func (sl *ServerList) GetServer(idx uint32) *ServerSpec {
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sl.Lock()
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defer sl.Unlock()
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for {
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if idx >= uint32(len(sl.servers)) {
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return nil
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}
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server := sl.servers[idx]
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if !server.IsValid() {
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sl.removeServer(idx)
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continue
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}
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return server
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}
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}
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func (sl *ServerList) removeServer(idx uint32) {
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n := len(sl.servers)
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sl.servers[idx] = sl.servers[n-1]
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sl.servers = sl.servers[:n-1]
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}
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type ServerPicker interface {
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PickServer() *ServerSpec
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}
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type RoundRobinServerPicker struct {
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sync.Mutex
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serverlist *ServerList
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nextIndex uint32
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}
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func NewRoundRobinServerPicker(serverlist *ServerList) *RoundRobinServerPicker {
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return &RoundRobinServerPicker{
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serverlist: serverlist,
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nextIndex: 0,
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}
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}
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func (p *RoundRobinServerPicker) PickServer() *ServerSpec {
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p.Lock()
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defer p.Unlock()
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next := p.nextIndex
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server := p.serverlist.GetServer(next)
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if server == nil {
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next = 0
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server = p.serverlist.GetServer(0)
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}
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next++
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if next >= p.serverlist.Size() {
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next = 0
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}
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p.nextIndex = next
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return server
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}
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