166 lines
3.1 KiB
Go
166 lines
3.1 KiB
Go
package client
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import (
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"errors"
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"math/rand"
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"sync"
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)
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const (
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poolSize = 10
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)
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var (
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ErrNotFound = errors.New("Server Not Found")
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)
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type PoolClient struct {
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*Client
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Rate int
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mutex sync.Mutex
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}
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type SelectionHandler func(map[string]*PoolClient, string) string
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func SelectWithRate(pool map[string]*PoolClient,
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last string) (addr string) {
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total := 0
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for _, item := range pool {
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total += item.Rate
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if rand.Intn(total) < item.Rate {
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return item.addr
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}
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}
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return last
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}
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func SelectRandom(pool map[string]*PoolClient,
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last string) (addr string) {
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r := rand.Intn(len(pool))
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i := 0
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for k, _ := range pool {
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if r == i {
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return k
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}
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i++
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}
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return last
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}
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type Pool struct {
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SelectionHandler SelectionHandler
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ErrorHandler ErrorHandler
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Clients map[string]*PoolClient
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last string
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mutex sync.Mutex
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}
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// NewPool returns a new pool.
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func NewPool() (pool *Pool) {
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return &Pool{
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Clients: make(map[string]*PoolClient, poolSize),
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SelectionHandler: SelectWithRate,
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}
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}
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// Add a server with rate.
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func (pool *Pool) Add(net, addr string, rate int) (err error) {
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pool.mutex.Lock()
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defer pool.mutex.Unlock()
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var item *PoolClient
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var ok bool
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if item, ok = pool.Clients[addr]; ok {
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item.Rate = rate
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} else {
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var client *Client
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client, err = New(net, addr)
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if err == nil {
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item = &PoolClient{Client: client, Rate: rate}
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pool.Clients[addr] = item
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}
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}
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return
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}
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// Remove a server.
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func (pool *Pool) Remove(addr string) {
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pool.mutex.Lock()
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defer pool.mutex.Unlock()
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delete(pool.Clients, addr)
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}
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func (pool *Pool) Do(funcname string, data []byte,
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flag byte, h ResponseHandler) (addr, handle string, err error) {
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client := pool.selectServer()
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client.Lock()
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defer client.Unlock()
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handle, err = client.Do(funcname, data, flag, h)
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addr = client.addr
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return
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}
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func (pool *Pool) DoBg(funcname string, data []byte,
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flag byte) (addr, handle string, err error) {
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client := pool.selectServer()
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client.Lock()
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defer client.Unlock()
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handle, err = client.DoBg(funcname, data, flag)
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addr = client.addr
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return
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}
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// Status gets job status from job server.
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// !!!Not fully tested.!!!
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func (pool *Pool) Status(addr, handle string) (status *Status, err error) {
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if client, ok := pool.Clients[addr]; ok {
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client.Lock()
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defer client.Unlock()
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status, err = client.Status(handle)
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} else {
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err = ErrNotFound
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}
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return
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}
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// Send a something out, get the samething back.
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func (pool *Pool) Echo(addr string, data []byte) (echo []byte, err error) {
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var client *PoolClient
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if addr == "" {
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client = pool.selectServer()
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} else {
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var ok bool
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if client, ok = pool.Clients[addr]; !ok {
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err = ErrNotFound
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return
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}
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}
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client.Lock()
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defer client.Unlock()
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echo, err = client.Echo(data)
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return
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}
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// Close
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func (pool *Pool) Close() (err map[string]error) {
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err = make(map[string]error)
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for _, c := range pool.Clients {
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err[c.addr] = c.Close()
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}
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return
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}
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// selecting server
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func (pool *Pool) selectServer() (client *PoolClient) {
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for client == nil {
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addr := pool.SelectionHandler(pool.Clients, pool.last)
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var ok bool
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if client, ok = pool.Clients[addr]; ok {
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pool.last = addr
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break
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}
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}
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return
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}
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