gitea/vendor/github.com/go-redis/redis/v8/internal/pool/pool.go

527 lines
9.7 KiB
Go
Raw Normal View History

package pool
import (
"context"
"errors"
"net"
"sync"
"sync/atomic"
"time"
"github.com/go-redis/redis/v8/internal"
)
var (
// ErrClosed performs any operation on the closed client will return this error.
ErrClosed = errors.New("redis: client is closed")
// ErrPoolTimeout timed out waiting to get a connection from the connection pool.
ErrPoolTimeout = errors.New("redis: connection pool timeout")
)
var timers = sync.Pool{
New: func() interface{} {
t := time.NewTimer(time.Hour)
t.Stop()
return t
},
}
// Stats contains pool state information and accumulated stats.
type Stats struct {
Hits uint32 // number of times free connection was found in the pool
Misses uint32 // number of times free connection was NOT found in the pool
Timeouts uint32 // number of times a wait timeout occurred
TotalConns uint32 // number of total connections in the pool
IdleConns uint32 // number of idle connections in the pool
StaleConns uint32 // number of stale connections removed from the pool
}
type Pooler interface {
NewConn(context.Context) (*Conn, error)
CloseConn(*Conn) error
Get(context.Context) (*Conn, error)
Put(context.Context, *Conn)
Remove(context.Context, *Conn, error)
Len() int
IdleLen() int
Stats() *Stats
Close() error
}
type Options struct {
Dialer func(context.Context) (net.Conn, error)
OnClose func(*Conn) error
PoolSize int
MinIdleConns int
MaxConnAge time.Duration
PoolTimeout time.Duration
IdleTimeout time.Duration
IdleCheckFrequency time.Duration
}
type lastDialErrorWrap struct {
err error
}
type ConnPool struct {
opt *Options
dialErrorsNum uint32 // atomic
lastDialError atomic.Value
queue chan struct{}
connsMu sync.Mutex
conns []*Conn
idleConns []*Conn
poolSize int
idleConnsLen int
stats Stats
_closed uint32 // atomic
closedCh chan struct{}
}
var _ Pooler = (*ConnPool)(nil)
func NewConnPool(opt *Options) *ConnPool {
p := &ConnPool{
opt: opt,
queue: make(chan struct{}, opt.PoolSize),
conns: make([]*Conn, 0, opt.PoolSize),
idleConns: make([]*Conn, 0, opt.PoolSize),
closedCh: make(chan struct{}),
}
p.connsMu.Lock()
p.checkMinIdleConns()
p.connsMu.Unlock()
if opt.IdleTimeout > 0 && opt.IdleCheckFrequency > 0 {
go p.reaper(opt.IdleCheckFrequency)
}
return p
}
func (p *ConnPool) checkMinIdleConns() {
if p.opt.MinIdleConns == 0 {
return
}
for p.poolSize < p.opt.PoolSize && p.idleConnsLen < p.opt.MinIdleConns {
p.poolSize++
p.idleConnsLen++
go func() {
err := p.addIdleConn()
if err != nil {
p.connsMu.Lock()
p.poolSize--
p.idleConnsLen--
p.connsMu.Unlock()
}
}()
}
}
func (p *ConnPool) addIdleConn() error {
cn, err := p.dialConn(context.TODO(), true)
if err != nil {
return err
}
p.connsMu.Lock()
p.conns = append(p.conns, cn)
p.idleConns = append(p.idleConns, cn)
p.connsMu.Unlock()
return nil
}
func (p *ConnPool) NewConn(ctx context.Context) (*Conn, error) {
return p.newConn(ctx, false)
}
func (p *ConnPool) newConn(ctx context.Context, pooled bool) (*Conn, error) {
cn, err := p.dialConn(ctx, pooled)
if err != nil {
return nil, err
}
p.connsMu.Lock()
p.conns = append(p.conns, cn)
if pooled {
// If pool is full remove the cn on next Put.
if p.poolSize >= p.opt.PoolSize {
cn.pooled = false
} else {
p.poolSize++
}
}
p.connsMu.Unlock()
return cn, nil
}
func (p *ConnPool) dialConn(ctx context.Context, pooled bool) (*Conn, error) {
if p.closed() {
return nil, ErrClosed
}
if atomic.LoadUint32(&p.dialErrorsNum) >= uint32(p.opt.PoolSize) {
return nil, p.getLastDialError()
}
netConn, err := p.opt.Dialer(ctx)
if err != nil {
p.setLastDialError(err)
if atomic.AddUint32(&p.dialErrorsNum, 1) == uint32(p.opt.PoolSize) {
go p.tryDial()
}
return nil, err
}
cn := NewConn(netConn)
cn.pooled = pooled
return cn, nil
}
func (p *ConnPool) tryDial() {
for {
if p.closed() {
return
}
conn, err := p.opt.Dialer(context.Background())
if err != nil {
p.setLastDialError(err)
time.Sleep(time.Second)
continue
}
atomic.StoreUint32(&p.dialErrorsNum, 0)
_ = conn.Close()
return
}
}
func (p *ConnPool) setLastDialError(err error) {
p.lastDialError.Store(&lastDialErrorWrap{err: err})
}
func (p *ConnPool) getLastDialError() error {
err, _ := p.lastDialError.Load().(*lastDialErrorWrap)
if err != nil {
return err.err
}
return nil
}
// Get returns existed connection from the pool or creates a new one.
func (p *ConnPool) Get(ctx context.Context) (*Conn, error) {
if p.closed() {
return nil, ErrClosed
}
if err := p.waitTurn(ctx); err != nil {
return nil, err
}
for {
p.connsMu.Lock()
cn := p.popIdle()
p.connsMu.Unlock()
if cn == nil {
break
}
if p.isStaleConn(cn) {
_ = p.CloseConn(cn)
continue
}
atomic.AddUint32(&p.stats.Hits, 1)
return cn, nil
}
atomic.AddUint32(&p.stats.Misses, 1)
newcn, err := p.newConn(ctx, true)
if err != nil {
p.freeTurn()
return nil, err
}
return newcn, nil
}
func (p *ConnPool) getTurn() {
p.queue <- struct{}{}
}
func (p *ConnPool) waitTurn(ctx context.Context) error {
select {
case <-ctx.Done():
return ctx.Err()
default:
}
select {
case p.queue <- struct{}{}:
return nil
default:
}
timer := timers.Get().(*time.Timer)
timer.Reset(p.opt.PoolTimeout)
select {
case <-ctx.Done():
if !timer.Stop() {
<-timer.C
}
timers.Put(timer)
return ctx.Err()
case p.queue <- struct{}{}:
if !timer.Stop() {
<-timer.C
}
timers.Put(timer)
return nil
case <-timer.C:
timers.Put(timer)
atomic.AddUint32(&p.stats.Timeouts, 1)
return ErrPoolTimeout
}
}
func (p *ConnPool) freeTurn() {
<-p.queue
}
func (p *ConnPool) popIdle() *Conn {
if len(p.idleConns) == 0 {
return nil
}
idx := len(p.idleConns) - 1
cn := p.idleConns[idx]
p.idleConns = p.idleConns[:idx]
p.idleConnsLen--
p.checkMinIdleConns()
return cn
}
func (p *ConnPool) Put(ctx context.Context, cn *Conn) {
if cn.rd.Buffered() > 0 {
internal.Logger.Printf(ctx, "Conn has unread data")
p.Remove(ctx, cn, BadConnError{})
return
}
if !cn.pooled {
p.Remove(ctx, cn, nil)
return
}
p.connsMu.Lock()
p.idleConns = append(p.idleConns, cn)
p.idleConnsLen++
p.connsMu.Unlock()
p.freeTurn()
}
func (p *ConnPool) Remove(ctx context.Context, cn *Conn, reason error) {
p.removeConnWithLock(cn)
p.freeTurn()
_ = p.closeConn(cn)
}
func (p *ConnPool) CloseConn(cn *Conn) error {
p.removeConnWithLock(cn)
return p.closeConn(cn)
}
func (p *ConnPool) removeConnWithLock(cn *Conn) {
p.connsMu.Lock()
p.removeConn(cn)
p.connsMu.Unlock()
}
func (p *ConnPool) removeConn(cn *Conn) {
for i, c := range p.conns {
if c == cn {
p.conns = append(p.conns[:i], p.conns[i+1:]...)
if cn.pooled {
p.poolSize--
p.checkMinIdleConns()
}
return
}
}
}
func (p *ConnPool) closeConn(cn *Conn) error {
if p.opt.OnClose != nil {
_ = p.opt.OnClose(cn)
}
return cn.Close()
}
// Len returns total number of connections.
func (p *ConnPool) Len() int {
p.connsMu.Lock()
n := len(p.conns)
p.connsMu.Unlock()
return n
}
// IdleLen returns number of idle connections.
func (p *ConnPool) IdleLen() int {
p.connsMu.Lock()
n := p.idleConnsLen
p.connsMu.Unlock()
return n
}
func (p *ConnPool) Stats() *Stats {
idleLen := p.IdleLen()
return &Stats{
Hits: atomic.LoadUint32(&p.stats.Hits),
Misses: atomic.LoadUint32(&p.stats.Misses),
Timeouts: atomic.LoadUint32(&p.stats.Timeouts),
TotalConns: uint32(p.Len()),
IdleConns: uint32(idleLen),
StaleConns: atomic.LoadUint32(&p.stats.StaleConns),
}
}
func (p *ConnPool) closed() bool {
return atomic.LoadUint32(&p._closed) == 1
}
func (p *ConnPool) Filter(fn func(*Conn) bool) error {
p.connsMu.Lock()
defer p.connsMu.Unlock()
var firstErr error
for _, cn := range p.conns {
if fn(cn) {
if err := p.closeConn(cn); err != nil && firstErr == nil {
firstErr = err
}
}
}
return firstErr
}
func (p *ConnPool) Close() error {
if !atomic.CompareAndSwapUint32(&p._closed, 0, 1) {
return ErrClosed
}
close(p.closedCh)
var firstErr error
p.connsMu.Lock()
for _, cn := range p.conns {
if err := p.closeConn(cn); err != nil && firstErr == nil {
firstErr = err
}
}
p.conns = nil
p.poolSize = 0
p.idleConns = nil
p.idleConnsLen = 0
p.connsMu.Unlock()
return firstErr
}
func (p *ConnPool) reaper(frequency time.Duration) {
ticker := time.NewTicker(frequency)
defer ticker.Stop()
for {
select {
case <-ticker.C:
// It is possible that ticker and closedCh arrive together,
// and select pseudo-randomly pick ticker case, we double
// check here to prevent being executed after closed.
if p.closed() {
return
}
_, err := p.ReapStaleConns()
if err != nil {
internal.Logger.Printf(context.Background(), "ReapStaleConns failed: %s", err)
continue
}
case <-p.closedCh:
return
}
}
}
func (p *ConnPool) ReapStaleConns() (int, error) {
var n int
for {
p.getTurn()
p.connsMu.Lock()
cn := p.reapStaleConn()
p.connsMu.Unlock()
p.freeTurn()
if cn != nil {
_ = p.closeConn(cn)
n++
} else {
break
}
}
atomic.AddUint32(&p.stats.StaleConns, uint32(n))
return n, nil
}
func (p *ConnPool) reapStaleConn() *Conn {
if len(p.idleConns) == 0 {
return nil
}
cn := p.idleConns[0]
if !p.isStaleConn(cn) {
return nil
}
p.idleConns = append(p.idleConns[:0], p.idleConns[1:]...)
p.idleConnsLen--
p.removeConn(cn)
return cn
}
func (p *ConnPool) isStaleConn(cn *Conn) bool {
if p.opt.IdleTimeout == 0 && p.opt.MaxConnAge == 0 {
return false
}
now := time.Now()
if p.opt.IdleTimeout > 0 && now.Sub(cn.UsedAt()) >= p.opt.IdleTimeout {
return true
}
if p.opt.MaxConnAge > 0 && now.Sub(cn.createdAt) >= p.opt.MaxConnAge {
return true
}
return false
}