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repository: wait max 1 minutes for lock removal if context is canceled

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The toplevel context in restic only canceled if the user interrupts a
restic operation. If the network connection has failed this can require
waiting the full retry duration of 15 minutes which is a bad user
experience for interactive usage. Thus limit the delay to one minute in
this case.
This commit is contained in:
Michael Eischer 2024-04-29 21:43:28 +02:00
parent 98709a4372
commit b1266867d2
3 changed files with 51 additions and 20 deletions
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2
internal/repository/lock.go
View file

@ -132,7 +132,7 @@ func (l *locker) refreshLocks(ctx context.Context, backend backend.Backend, lock
// remove the lock from the repo
debug.Log("unlocking repository with lock %v", lock)
if err := lock.Unlock(); err != nil {
if err := lock.Unlock(ctx); err != nil {
debug.Log("error while unlocking: %v", err)
logger("error while unlocking: %v", err)
}

45
internal/restic/lock.go
View file

@ -17,6 +17,10 @@ import (
"github.com/restic/restic/internal/debug"
)
// UnlockCancelDelay bounds the duration how long lock cleanup operations will wait
// if the passed in context was canceled.
const UnlockCancelDelay time.Duration = 1 * time.Minute
// Lock represents a process locking the repository for an operation.
//
// There are two types of locks: exclusive and non-exclusive. There may be many
@ -136,7 +140,7 @@ func newLock(ctx context.Context, repo Unpacked, excl bool) (*Lock, error) {
time.Sleep(waitBeforeLockCheck)
if err = lock.checkForOtherLocks(ctx); err != nil {
_ = lock.Unlock()
_ = lock.Unlock(ctx)
return nil, err
}
@ -220,12 +224,15 @@ func (l *Lock) createLock(ctx context.Context) (ID, error) {
}
// Unlock removes the lock from the repository.
func (l *Lock) Unlock() error {
func (l *Lock) Unlock(ctx context.Context) error {
if l == nil || l.lockID == nil {
return nil
}
return l.repo.RemoveUnpacked(context.TODO(), LockFile, *l.lockID)
ctx, cancel := delayedCancelContext(ctx, UnlockCancelDelay)
defer cancel()
return l.repo.RemoveUnpacked(ctx, LockFile, *l.lockID)
}
var StaleLockTimeout = 30 * time.Minute
@ -266,6 +273,23 @@ func (l *Lock) Stale() bool {
return false
}
func delayedCancelContext(parentCtx context.Context, delay time.Duration) (context.Context, context.CancelFunc) {
ctx, cancel := context.WithCancel(context.Background())
go func() {
select {
case <-parentCtx.Done():
case <-ctx.Done():
return
}
time.Sleep(delay)
cancel()
}()
return ctx, cancel
}
// Refresh refreshes the lock by creating a new file in the backend with a new
// timestamp. Afterwards the old lock is removed.
func (l *Lock) Refresh(ctx context.Context) error {
@ -285,7 +309,10 @@ func (l *Lock) Refresh(ctx context.Context) error {
oldLockID := l.lockID
l.lockID = &id
return l.repo.RemoveUnpacked(context.TODO(), LockFile, *oldLockID)
ctx, cancel := delayedCancelContext(ctx, UnlockCancelDelay)
defer cancel()
return l.repo.RemoveUnpacked(ctx, LockFile, *oldLockID)
}
// RefreshStaleLock is an extended variant of Refresh that can also refresh stale lock files.
@ -312,15 +339,19 @@ func (l *Lock) RefreshStaleLock(ctx context.Context) error {
time.Sleep(waitBeforeLockCheck)
exists, err = l.checkExistence(ctx)
ctx, cancel := delayedCancelContext(ctx, UnlockCancelDelay)
defer cancel()
if err != nil {
// cleanup replacement lock
_ = l.repo.RemoveUnpacked(context.TODO(), LockFile, id)
_ = l.repo.RemoveUnpacked(ctx, LockFile, id)
return err
}
if !exists {
// cleanup replacement lock
_ = l.repo.RemoveUnpacked(context.TODO(), LockFile, id)
_ = l.repo.RemoveUnpacked(ctx, LockFile, id)
return ErrRemovedLock
}
@ -331,7 +362,7 @@ func (l *Lock) RefreshStaleLock(ctx context.Context) error {
oldLockID := l.lockID
l.lockID = &id
return l.repo.RemoveUnpacked(context.TODO(), LockFile, *oldLockID)
return l.repo.RemoveUnpacked(ctx, LockFile, *oldLockID)
}
func (l *Lock) checkExistence(ctx context.Context) (bool, error) {

24
internal/restic/lock_test.go
View file

@ -22,7 +22,7 @@ func TestLock(t *testing.T) {
lock, err := restic.NewLock(context.TODO(), repo)
rtest.OK(t, err)
rtest.OK(t, lock.Unlock())
rtest.OK(t, lock.Unlock(context.TODO()))
}
func TestDoubleUnlock(t *testing.T) {
@ -32,9 +32,9 @@ func TestDoubleUnlock(t *testing.T) {
lock, err := restic.NewLock(context.TODO(), repo)
rtest.OK(t, err)
rtest.OK(t, lock.Unlock())
rtest.OK(t, lock.Unlock(context.TODO()))
err = lock.Unlock()
err = lock.Unlock(context.TODO())
rtest.Assert(t, err != nil,
"double unlock didn't return an error, got %v", err)
}
@ -49,8 +49,8 @@ func TestMultipleLock(t *testing.T) {
lock2, err := restic.NewLock(context.TODO(), repo)
rtest.OK(t, err)
rtest.OK(t, lock1.Unlock())
rtest.OK(t, lock2.Unlock())
rtest.OK(t, lock1.Unlock(context.TODO()))
rtest.OK(t, lock2.Unlock(context.TODO()))
}
type failLockLoadingBackend struct {
@ -75,7 +75,7 @@ func TestMultipleLockFailure(t *testing.T) {
_, err = restic.NewLock(context.TODO(), repo)
rtest.Assert(t, err != nil, "unreadable lock file did not result in an error")
rtest.OK(t, lock1.Unlock())
rtest.OK(t, lock1.Unlock(context.TODO()))
}
func TestLockExclusive(t *testing.T) {
@ -83,7 +83,7 @@ func TestLockExclusive(t *testing.T) {
elock, err := restic.NewExclusiveLock(context.TODO(), repo)
rtest.OK(t, err)
rtest.OK(t, elock.Unlock())
rtest.OK(t, elock.Unlock(context.TODO()))
}
func TestLockOnExclusiveLockedRepo(t *testing.T) {
@ -99,8 +99,8 @@ func TestLockOnExclusiveLockedRepo(t *testing.T) {
rtest.Assert(t, restic.IsAlreadyLocked(err),
"create normal lock with exclusively locked repo didn't return the correct error")
rtest.OK(t, lock.Unlock())
rtest.OK(t, elock.Unlock())
rtest.OK(t, lock.Unlock(context.TODO()))
rtest.OK(t, elock.Unlock(context.TODO()))
}
func TestExclusiveLockOnLockedRepo(t *testing.T) {
@ -116,8 +116,8 @@ func TestExclusiveLockOnLockedRepo(t *testing.T) {
rtest.Assert(t, restic.IsAlreadyLocked(err),
"create normal lock with exclusively locked repo didn't return the correct error")
rtest.OK(t, lock.Unlock())
rtest.OK(t, elock.Unlock())
rtest.OK(t, lock.Unlock(context.TODO()))
rtest.OK(t, elock.Unlock(context.TODO()))
}
func createFakeLock(repo restic.SaverUnpacked, t time.Time, pid int) (restic.ID, error) {
@ -296,7 +296,7 @@ func testLockRefresh(t *testing.T, refresh func(lock *restic.Lock) error) {
rtest.OK(t, err)
rtest.Assert(t, lock2.Time.After(time0),
"expected a later timestamp after lock refresh")
rtest.OK(t, lock.Unlock())
rtest.OK(t, lock.Unlock(context.TODO()))
}
func TestLockRefresh(t *testing.T) {