140 lines
2.4 KiB
Go
140 lines
2.4 KiB
Go
package pool
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import (
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"fmt"
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"io"
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"sync"
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"time"
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)
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//TODO: 保存所有的连接, 而不是只保存连接计数
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var ErrMaxConn = fmt.Errorf("maximum connections reached")
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//
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type NConn interface {
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io.Closer
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Name() string
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Closed() bool
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}
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type ConnPool struct {
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sync.RWMutex
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Name string
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Address string
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MaxConns int
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MaxIdle int
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Cnt int64
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New func(name string) (NConn, error)
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active int
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free []NConn
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all map[string]NConn
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}
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func NewConnPool(name string, address string, maxConns int, maxIdle int) *ConnPool {
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return &ConnPool{Name: name, Address: address, MaxConns: maxConns, MaxIdle: maxIdle, Cnt: 0, all: make(map[string]NConn)}
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}
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func (this *ConnPool) Proc() string {
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this.RLock()
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defer this.RUnlock()
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return fmt.Sprintf("Name:%s,Cnt:%d,active:%d,all:%d,free:%d",
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this.Name, this.Cnt, this.active, len(this.all), len(this.free))
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}
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func (this *ConnPool) Fetch() (NConn, error) {
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this.Lock()
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defer this.Unlock()
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conn := this.fetchFree()
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if conn != nil {
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return conn, nil
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}
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if this.overMax() {
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return nil, ErrMaxConn
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}
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conn, err := this.newConn()
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if err != nil {
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return nil, err
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}
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this.increActive()
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return conn, nil
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}
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func (this *ConnPool) ForceClose(conn NConn) {
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this.Lock()
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defer this.Unlock()
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this.deleteConn(conn)
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this.decreActive()
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}
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func (this *ConnPool) Release(conn NConn) {
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this.Lock()
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defer this.Unlock()
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if this.overMaxIdle() {
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this.deleteConn(conn)
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this.decreActive()
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} else {
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this.addFree(conn)
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}
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}
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// internal, concurrently unsafe
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func (this *ConnPool) newConn() (NConn, error) {
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name := fmt.Sprintf("%s_%d_%d", this.Name, this.Cnt, time.Now().Unix())
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conn, err := this.New(name)
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if err != nil {
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if conn != nil {
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conn.Close()
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}
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return nil, err
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}
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this.Cnt++
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this.all[conn.Name()] = conn
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return conn, nil
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}
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func (this *ConnPool) fetchFree() NConn {
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if len(this.free) == 0 {
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return nil
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}
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conn := this.free[0]
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this.free = this.free[1:]
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return conn
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}
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func (this *ConnPool) addFree(conn NConn) {
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this.free = append(this.free, conn)
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}
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func (this *ConnPool) overMax() bool {
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return this.active >= this.MaxConns
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}
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func (this *ConnPool) overMaxIdle() bool {
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return len(this.free) >= this.MaxIdle
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}
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func (this *ConnPool) increActive() {
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this.active += 1
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}
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func (this *ConnPool) decreActive() {
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this.active -= 1
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}
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func (this *ConnPool) deleteConn(conn NConn) {
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if conn != nil {
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conn.Close()
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}
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delete(this.all, conn.Name())
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}
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