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redis.go
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redis.go
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package redis
import (
"time"
"github.com/go-locks/distlock/driver"
"github.com/gomodule/redigo/redis"
"github.com/letsfire/redigo"
"github.com/letsfire/redisc"
"github.com/sirupsen/logrus"
)
var (
MaxReaders = 1 << 30
MinWatchRetryInterval = time.Millisecond
MaxWatchRetryInterval = time.Second * 16
)
type redisDriver struct {
quorum int
cluster bool
redigo []*redigo.Redigo
}
var _ driver.IWatcher = &redisDriver{}
var _ driver.IDriver = &redisDriver{}
var _ driver.IRWDriver = &redisDriver{}
func New(redigo ...*redigo.Redigo) *redisDriver {
for _, rg := range redigo {
rg.Exec(func(c redis.Conn) (res interface{}, err error) {
lockScript.Load(c)
unlockScript.Load(c)
touchScript.Load(c)
readLockScript.Load(c)
readUnlockScript.Load(c)
writeLockScript.Load(c)
writeUnlockScript.Load(c)
readWriteTouchScript.Load(c)
return
})
}
return &redisDriver{
redigo: redigo,
quorum: (len(redigo) / 2) + 1,
cluster: redigo[0].Mode() == "cluster",
}
}
func (rd *redisDriver) channelName(name string) string {
return "unlock-notify-channel-{" + name + "}"
}
func (rd *redisDriver) doLock(fn func(rg *redigo.Redigo) int) (bool, time.Duration) {
counter := rd.quorum
for _, rg := range rd.redigo {
for {
if wait := fn(rg); wait == 0 {
continue
} else if wait == -3 {
counter -= 1
if counter == 0 {
return true, 0
}
} else if wait > 0 {
return false, time.Duration(wait) * time.Millisecond
}
break
}
}
return false, -1
}
func (rd *redisDriver) doTouch(fn func(rg *redigo.Redigo) bool) bool {
counter := rd.quorum
for _, rg := range rd.redigo {
if fn(rg) {
counter -= 1
if counter == 0 {
return true
}
}
}
return false
}
func (rd *redisDriver) Lock(name, value string, expiry time.Duration) (bool, time.Duration) {
msExpiry := int(expiry / time.Millisecond)
return rd.doLock(func(rg *redigo.Redigo) int {
wait, err := rg.Int(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name)
}
return lockScript.Do(c, name, value, msExpiry)
})
if err != nil || wait == -1 {
wait = -1 // less than zero, use the default wait duration
logrus.WithError(err).Errorf("redis acquire lock '%s' failed", name)
}
return wait
})
}
func (rd *redisDriver) Unlock(name, value string) {
channel := rd.channelName(name)
for _, rg := range rd.redigo {
_, err := rg.Exec(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name, channel)
}
return unlockScript.Do(c, name, channel, value)
})
if err != nil {
logrus.WithError(err).Errorf("redis release lock '%s' failed", name)
}
}
}
func (rd *redisDriver) Touch(name, value string, expiry time.Duration) bool {
msExpiry := int(expiry / time.Millisecond)
return rd.doTouch(func(rg *redigo.Redigo) bool {
ok, err := rg.Bool(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name)
}
return touchScript.Do(c, name, value, msExpiry)
})
if err != nil {
logrus.WithError(err).Errorf("redis touch lock '%s' failed", name)
}
return ok
})
}
func (rd *redisDriver) RLock(name, value string, expiry time.Duration) (bool, time.Duration) {
msExpiry := int(expiry / time.Millisecond)
return rd.doLock(func(rg *redigo.Redigo) int {
wait, err := rg.Int(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name)
}
return readLockScript.Do(c, name, value, msExpiry)
})
if err != nil || wait == -1 {
wait = -1 // less than zero, use the default wait duration
logrus.WithError(err).Errorf("redis acquire read lock '%s' failed", name)
}
return wait
})
}
func (rd *redisDriver) RUnlock(name, value string) {
channel := rd.channelName(name)
for _, rg := range rd.redigo {
_, err := rg.Exec(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name, channel)
}
return readUnlockScript.Do(c, name, channel, value, MaxReaders)
})
if err != nil {
logrus.WithError(err).Errorf("redis release read lock '%s' failed", name)
}
}
}
func (rd *redisDriver) RTouch(name, value string, expiry time.Duration) bool {
msExpiry := int(expiry / time.Millisecond)
return rd.doTouch(func(rg *redigo.Redigo) bool {
ok, err := rg.Bool(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name)
}
return readWriteTouchScript.Do(c, name, value, msExpiry)
})
if err != nil {
logrus.WithError(err).Errorf("redis touch lock '%s' failed", name)
}
return ok
})
}
func (rd *redisDriver) WLock(name, value string, expiry time.Duration) (bool, time.Duration) {
msExpiry := int(expiry / time.Millisecond)
return rd.doLock(func(rg *redigo.Redigo) int {
wait, err := rg.Int(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name)
}
return writeLockScript.Do(c, name, value, msExpiry, MaxReaders)
})
if err != nil || wait == -1 {
wait = -1 // less than zero, use the default wait duration
logrus.WithError(err).Errorf("redis acquire write lock '%s' failed", name)
}
return wait
})
}
func (rd *redisDriver) WUnlock(name, value string) {
channel := rd.channelName(name)
for _, rg := range rd.redigo {
_, err := rg.Exec(func(c redis.Conn) (res interface{}, err error) {
if rd.cluster {
redisc.BindConn(c, name, channel)
}
return writeUnlockScript.Do(c, name, channel, value, MaxReaders)
})
if err != nil {
logrus.WithError(err).Errorf("redis release write lock '%s' failed", name)
}
}
}
func (rd *redisDriver) WTouch(name, value string, expiry time.Duration) bool {
return rd.RTouch(name, value, expiry)
}
func (rd *redisDriver) Watch(name string) <-chan struct{} {
channel := rd.channelName(name)
outChan := make(chan struct{})
for _, rg := range rd.redigo {
go func(rg *redigo.Redigo) {
errSleepDuration := MinWatchRetryInterval
for {
err := rg.Sub(func(c redis.PubSubConn) error {
if rd.cluster {
err := redisc.BindConn(c.Conn, channel)
if err != nil {
return err
}
}
if err := c.Subscribe(channel); err != nil {
return err
}
errSleepDuration = MinWatchRetryInterval
for {
switch v := c.ReceiveWithTimeout(0).(type) {
case redis.Message:
outChan <- struct{}{}
case error:
return v
}
}
})
if err != nil {
logrus.WithError(err).Errorf("redis watch channel '%s' abort", channel)
time.Sleep(errSleepDuration) // may be the redis server is down
if errSleepDuration *= 2; errSleepDuration > MaxWatchRetryInterval {
errSleepDuration = MaxWatchRetryInterval
}
}
}
}(rg)
}
return outChan
}