mirror of https://github.com/restic/restic.git
134 lines
3.0 KiB
Go
134 lines
3.0 KiB
Go
package main
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import (
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"context"
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"fmt"
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"os"
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"sync"
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"time"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/repository"
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"github.com/restic/restic/internal/restic"
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)
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var globalLocks struct {
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locks []*restic.Lock
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cancelRefresh chan struct{}
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refreshWG sync.WaitGroup
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sync.Mutex
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}
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func lockRepo(repo *repository.Repository) (*restic.Lock, error) {
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return lockRepository(repo, false)
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}
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func lockRepoExclusive(repo *repository.Repository) (*restic.Lock, error) {
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return lockRepository(repo, true)
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}
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func lockRepository(repo *repository.Repository, exclusive bool) (*restic.Lock, error) {
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lockFn := restic.NewLock
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if exclusive {
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lockFn = restic.NewExclusiveLock
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}
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lock, err := lockFn(context.TODO(), repo)
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if err != nil {
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return nil, errors.Fatalf("unable to create lock in backend: %v", err)
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}
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debug.Log("create lock %p (exclusive %v)", lock, exclusive)
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globalLocks.Lock()
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if globalLocks.cancelRefresh == nil {
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debug.Log("start goroutine for lock refresh")
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globalLocks.cancelRefresh = make(chan struct{})
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globalLocks.refreshWG = sync.WaitGroup{}
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globalLocks.refreshWG.Add(1)
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go refreshLocks(&globalLocks.refreshWG, globalLocks.cancelRefresh)
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}
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globalLocks.locks = append(globalLocks.locks, lock)
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globalLocks.Unlock()
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return lock, err
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}
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var refreshInterval = 5 * time.Minute
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func refreshLocks(wg *sync.WaitGroup, done <-chan struct{}) {
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debug.Log("start")
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defer func() {
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wg.Done()
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globalLocks.Lock()
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globalLocks.cancelRefresh = nil
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globalLocks.Unlock()
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}()
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ticker := time.NewTicker(refreshInterval)
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for {
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select {
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case <-done:
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debug.Log("terminate")
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return
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case <-ticker.C:
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debug.Log("refreshing locks")
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globalLocks.Lock()
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for _, lock := range globalLocks.locks {
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err := lock.Refresh(context.TODO())
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if err != nil {
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fmt.Fprintf(os.Stderr, "unable to refresh lock: %v\n", err)
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}
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}
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globalLocks.Unlock()
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}
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}
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}
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func unlockRepo(lock *restic.Lock) error {
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globalLocks.Lock()
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defer globalLocks.Unlock()
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for i := 0; i < len(globalLocks.locks); i++ {
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if lock == globalLocks.locks[i] {
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// remove the lock from the repo
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debug.Log("unlocking repository with lock %v", lock)
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if err := lock.Unlock(); err != nil {
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debug.Log("error while unlocking: %v", err)
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return err
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}
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// remove the lock from the list of locks
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globalLocks.locks = append(globalLocks.locks[:i], globalLocks.locks[i+1:]...)
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return nil
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}
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}
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debug.Log("unable to find lock %v in the global list of locks, ignoring", lock)
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return nil
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}
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func unlockAll() error {
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globalLocks.Lock()
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defer globalLocks.Unlock()
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debug.Log("unlocking %d locks", len(globalLocks.locks))
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for _, lock := range globalLocks.locks {
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if err := lock.Unlock(); err != nil {
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debug.Log("error while unlocking: %v", err)
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return err
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}
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debug.Log("successfully removed lock")
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}
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globalLocks.locks = globalLocks.locks[:0]
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return nil
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}
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func init() {
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AddCleanupHandler(unlockAll)
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}
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