go-redisson
a Redisson like distributed locking implementation using Redis.
Installation
go get github.com/cheerego/go-redisson
Lock Category
- Mutex
- 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
- Exclusive Reentrant Lock.
- use it like java redisson.
- a reentrant lock that can lock many times in a same goroutine.
Features
- tryLock，if waitTime > 0, wait
waitTimemilliseconds 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.
Options
WatchDogTimeout
g := godisson.NewGodisson(rdb, godisson.WithWatchDogTimeout(30*time.Second))
Examples
Mutex
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()
}()
}
">
package examples import ( "github.com/cheerego/godisson" "github.com/go-redis/redis/v8" "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() }() }
RLock
package examples
import (
"github.com/cheerego/godisson"
"github.com/go-redis/redis/v8"
"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()
}
