a Redisson like distributed locking implementation using Redis.
Explanation
go get github.com/ggdream/go-redisson
-
Mutex Example
- Exclusive Lock (X Lock).
- use it like std package sync.Mutex.
- not a reentrant lock that can't lock twice in a same goroutine.
-
RLock Example
- Exclusive Reentrant Lock.
- use it like java redisson.
- a reentrant lock that can lock many times in a same goroutine.
- tryLock,if waitTime > 0, wait
waitTime
milliseconds to try to obtain lock by while true and redis pub sub. - watchdog, if leaseTime = -1, start a time.Ticker(defaultWatchDogTime / 3) to renew lock expiration time.
g := godisson.NewGodisson(rdb, godisson.WithWatchDogTimeout(30*time.Second))
package main
import (
"github.com/ggdream/go-redisson"
"github.com/redis/go-redis/v9"
"github.com/pkg/errors"
"log"
"time"
)
func main() {
// create redis client
rdb := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
Password: "", // no password set
DB: 0, // use default DB
})
defer rdb.Close()
g := godisson.NewGodisson(rdb, godisson.WithWatchDogTimeout(30*time.Second))
test1(g)
test2(g)
}
// can't obtain lock in a same goroutine
func test1(g *godisson.Godisson) {
m1 := g.NewMutex("godisson")
m2 := g.NewMutex("godisson")
err := m1.TryLock(-1, 20000)
if errors.Is(err, godisson.ErrLockNotObtained) {
log.Println("can't obtained lock")
} else if err != nil {
log.Fatalln(err)
}
defer m1.Unlock()
// because waitTime = -1, waitTime < 0, try once, will return ErrLockNotObtained
err = m2.TryLock(-1, 20000)
if errors.Is(err, godisson.ErrLockNotObtained) {
log.Println("m2 must not obtained lock")
} else if err != nil {
log.Fatalln(err)
}
time.Sleep(10 * time.Second)
}
func test2(g *godisson.Godisson) {
m1 := g.NewMutex("godisson")
m2 := g.NewMutex("godisson")
go func() {
err := m1.TryLock(-1, 20000)
if errors.Is(err, godisson.ErrLockNotObtained) {
log.Println("can't obtained lock")
} else if err != nil {
log.Fatalln(err)
}
time.Sleep(10 * time.Second)
m1.Unlock()
}()
// waitTime > 0, after 10 milliseconds will obtain the lock
go func() {
time.Sleep(1 * time.Second)
err := m2.TryLock(15000, 20000)
if errors.Is(err, godisson.ErrLockNotObtained) {
log.Println("m2 must not obtained lock")
} else if err != nil {
log.Fatalln(err)
}
time.Sleep(10 * time.Second)
m2.Unlock()
}()
time.Sleep(20 * time.Second)
}
package main
import (
"github.com/ggdream/go-redisson"
"github.com/redis/go-redis/v9"
"log"
"time"
)
func main() {
// create redis client
rdb := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
Password: "", // no password set
DB: 0, // use default DB
})
defer rdb.Close()
g := godisson.NewGodisson(rdb, godisson.WithWatchDogTimeout(30*time.Second))
// lock with watchdog without retry
lock := g.NewRLock("godisson")
err := lock.Lock()
if err == godisson.ErrLockNotObtained {
log.Println("Could not obtain lock")
} else if err != nil {
log.Fatalln(err)
}
defer lock.Unlock()
// lock with retry、watchdog
// leaseTime value is -1, enable watchdog
lock2 := g.NewRLock("godission-try-watchdog")
err = lock2.TryLock(20000, -1)
if err == godisson.ErrLockNotObtained {
log.Println("Could not obtain lock")
} else if err != nil {
log.Fatalln(err)
}
time.Sleep(10 * time.Second)
defer lock.Unlock()
}