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package cluster
import (
"context"
"fmt"
"time"
"github.com/seaweedfs/seaweedfs/weed/cluster/lock_manager"
"github.com/seaweedfs/seaweedfs/weed/glog"
"github.com/seaweedfs/seaweedfs/weed/pb"
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"github.com/seaweedfs/seaweedfs/weed/util"
"google.golang.org/grpc"
)
type LockClient struct {
grpcDialOption grpc.DialOption
maxLockDuration time.Duration
sleepDuration time.Duration
seedFiler pb.ServerAddress
}
func NewLockClient(grpcDialOption grpc.DialOption, seedFiler pb.ServerAddress) *LockClient {
return &LockClient{
grpcDialOption: grpcDialOption,
maxLockDuration: 5 * time.Second,
sleepDuration: 2473 * time.Millisecond,
seedFiler: seedFiler,
}
}
type LiveLock struct {
key string
renewToken string
expireAtNs int64
hostFiler pb.ServerAddress
cancelCh chan struct{}
grpcDialOption grpc.DialOption
isLocked bool
self string
lc *LockClient
owner string
}
// NewShortLivedLock creates a lock with a 5-second duration
func (lc *LockClient) NewShortLivedLock(key string, owner string) (lock *LiveLock) {
lock = &LiveLock{
key: key,
hostFiler: lc.seedFiler,
cancelCh: make(chan struct{}),
expireAtNs: time.Now().Add(5 * time.Second).UnixNano(),
grpcDialOption: lc.grpcDialOption,
self: owner,
lc: lc,
}
lock.retryUntilLocked(5 * time.Second)
return
}
// StartLongLivedLock starts a goroutine to lock the key and returns immediately.
func (lc *LockClient) StartLongLivedLock(key string, owner string, onLockOwnerChange func(newLockOwner string)) (lock *LiveLock) {
lock = &LiveLock{
key: key,
hostFiler: lc.seedFiler,
cancelCh: make(chan struct{}),
expireAtNs: time.Now().Add(lock_manager.LiveLockTTL).UnixNano(),
grpcDialOption: lc.grpcDialOption,
self: owner,
lc: lc,
}
go func() {
isLocked := false
lockOwner := ""
for {
// Check for cancellation BEFORE attempting to lock to avoid race condition
// where Stop() is called after sleep but before lock attempt
select {
case <-lock.cancelCh:
return
default:
}
if isLocked {
if err := lock.AttemptToLock(lock_manager.LiveLockTTL); err != nil {
glog.V(0).Infof("Lost lock %s: %v", key, err)
isLocked = false
}
} else {
if err := lock.AttemptToLock(lock_manager.LiveLockTTL); err == nil {
isLocked = true
}
}
if lockOwner != lock.LockOwner() && lock.LockOwner() != "" {
glog.V(0).Infof("Lock owner changed from %s to %s", lockOwner, lock.LockOwner())
onLockOwnerChange(lock.LockOwner())
lockOwner = lock.LockOwner()
}
select {
case <-lock.cancelCh:
return
default:
time.Sleep(lock_manager.RenewInterval)
}
}
}()
return
}
func (lock *LiveLock) retryUntilLocked(lockDuration time.Duration) {
util.RetryUntil("create lock:"+lock.key, func() error {
return lock.AttemptToLock(lockDuration)
}, func(err error) (shouldContinue bool) {
if err != nil {
glog.Warningf("create lock %s: %s", lock.key, err)
}
return lock.renewToken == ""
})
}
func (lock *LiveLock) AttemptToLock(lockDuration time.Duration) error {
glog.V(4).Infof("LOCK: AttemptToLock key=%s owner=%s", lock.key, lock.self)
errorMessage, err := lock.doLock(lockDuration)
if err != nil {
glog.V(1).Infof("LOCK: doLock failed for key=%s: %v", lock.key, err)
time.Sleep(time.Second)
return err
}
if errorMessage != "" {
glog.V(1).Infof("LOCK: doLock returned error message for key=%s: %s", lock.key, errorMessage)
time.Sleep(time.Second)
return fmt.Errorf("%v", errorMessage)
}
if !lock.isLocked {
// Only log when transitioning from unlocked to locked
glog.V(1).Infof("LOCK: Successfully acquired key=%s owner=%s", lock.key, lock.self)
}
lock.isLocked = true
return nil
}
func (lock *LiveLock) StopShortLivedLock() error {
if !lock.isLocked {
return nil
}
defer func() {
lock.isLocked = false
}()
return pb.WithFilerClient(false, 0, lock.hostFiler, lock.grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
_, err := client.DistributedUnlock(context.Background(), &filer_pb.UnlockRequest{
Name: lock.key,
RenewToken: lock.renewToken,
})
return err
})
}
// Stop stops a long-lived lock by closing the cancel channel and releasing the lock
func (lock *LiveLock) Stop() error {
// Close the cancel channel to stop the long-lived lock goroutine
select {
case <-lock.cancelCh:
// Already closed
default:
close(lock.cancelCh)
}
// Wait a brief moment for the goroutine to see the closed channel
// This reduces the race condition window where the goroutine might
// attempt one more lock operation after we've released the lock
time.Sleep(10 * time.Millisecond)
// Also release the lock if held
// Note: We intentionally don't clear renewToken here because
// StopShortLivedLock needs it to properly unlock
return lock.StopShortLivedLock()
}
func (lock *LiveLock) doLock(lockDuration time.Duration) (errorMessage string, err error) {
glog.V(4).Infof("LOCK: doLock calling DistributedLock - key=%s filer=%s owner=%s",
lock.key, lock.hostFiler, lock.self)
previousHostFiler := lock.hostFiler
previousOwner := lock.owner
err = pb.WithFilerClient(false, 0, lock.hostFiler, lock.grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
resp, err := client.DistributedLock(context.Background(), &filer_pb.LockRequest{
Name: lock.key,
SecondsToLock: int64(lockDuration.Seconds()),
RenewToken: lock.renewToken,
IsMoved: false,
Owner: lock.self,
})
glog.V(4).Infof("LOCK: DistributedLock response - key=%s err=%v", lock.key, err)
if err == nil && resp != nil {
lock.renewToken = resp.RenewToken
glog.V(4).Infof("LOCK: Got renewToken for key=%s", lock.key)
} else {
//this can be retried. Need to remember the last valid renewToken
lock.renewToken = ""
glog.V(1).Infof("LOCK: Cleared renewToken for key=%s (err=%v)", lock.key, err)
}
if resp != nil {
errorMessage = resp.Error
if resp.LockHostMovedTo != "" && resp.LockHostMovedTo != string(previousHostFiler) {
// Only log if the host actually changed
glog.V(1).Infof("LOCK: Host changed from %s to %s for key=%s", previousHostFiler, resp.LockHostMovedTo, lock.key)
lock.hostFiler = pb.ServerAddress(resp.LockHostMovedTo)
lock.lc.seedFiler = lock.hostFiler
} else if resp.LockHostMovedTo != "" {
lock.hostFiler = pb.ServerAddress(resp.LockHostMovedTo)
}
if resp.LockOwner != "" && resp.LockOwner != previousOwner {
// Only log if the owner actually changed
glog.V(1).Infof("LOCK: Owner changed from %s to %s for key=%s", previousOwner, resp.LockOwner, lock.key)
lock.owner = resp.LockOwner
} else if resp.LockOwner != "" {
lock.owner = resp.LockOwner
} else if previousOwner != "" {
glog.V(1).Infof("LOCK: Owner cleared for key=%s", lock.key)
lock.owner = ""
}
}
return err
})
return
}
func (lock *LiveLock) LockOwner() string {
return lock.owner
}
|
