package scheduler import ( "context" "encoding/json" "fmt" "sync" "time" dcontext "github.com/docker/distribution/context" "github.com/docker/distribution/reference" "github.com/docker/distribution/registry/storage/driver" ) // onTTLExpiryFunc is called when a repository's TTL expires type expiryFunc func(reference.Reference) error const ( entryTypeBlob = iota entryTypeManifest indexSaveFrequency = 5 * time.Second ) // schedulerEntry represents an entry in the scheduler // fields are exported for serialization type schedulerEntry struct { Key string `json:"Key"` Expiry time.Time `json:"ExpiryData"` EntryType int `json:"EntryType"` timer *time.Timer } // New returns a new instance of the scheduler func New(ctx context.Context, driver driver.StorageDriver, path string) *TTLExpirationScheduler { return &TTLExpirationScheduler{ entries: make(map[string]*schedulerEntry), driver: driver, pathToStateFile: path, ctx: ctx, stopped: true, doneChan: make(chan struct{}), saveTimer: time.NewTicker(indexSaveFrequency), } } // TTLExpirationScheduler is a scheduler used to perform actions // when TTLs expire type TTLExpirationScheduler struct { sync.Mutex entries map[string]*schedulerEntry driver driver.StorageDriver ctx context.Context pathToStateFile string stopped bool onBlobExpire expiryFunc onManifestExpire expiryFunc indexDirty bool saveTimer *time.Ticker doneChan chan struct{} } // OnBlobExpire is called when a scheduled blob's TTL expires func (ttles *TTLExpirationScheduler) OnBlobExpire(f expiryFunc) { ttles.Lock() defer ttles.Unlock() ttles.onBlobExpire = f } // OnManifestExpire is called when a scheduled manifest's TTL expires func (ttles *TTLExpirationScheduler) OnManifestExpire(f expiryFunc) { ttles.Lock() defer ttles.Unlock() ttles.onManifestExpire = f } // AddBlob schedules a blob cleanup after ttl expires func (ttles *TTLExpirationScheduler) AddBlob(blobRef reference.Canonical, ttl time.Duration) error { ttles.Lock() defer ttles.Unlock() if ttles.stopped { return fmt.Errorf("scheduler not started") } ttles.add(blobRef, ttl, entryTypeBlob) return nil } // AddManifest schedules a manifest cleanup after ttl expires func (ttles *TTLExpirationScheduler) AddManifest(manifestRef reference.Canonical, ttl time.Duration) error { ttles.Lock() defer ttles.Unlock() if ttles.stopped { return fmt.Errorf("scheduler not started") } ttles.add(manifestRef, ttl, entryTypeManifest) return nil } // Start starts the scheduler func (ttles *TTLExpirationScheduler) Start() error { ttles.Lock() defer ttles.Unlock() err := ttles.readState() if err != nil { return err } if !ttles.stopped { return fmt.Errorf("Scheduler already started") } dcontext.GetLogger(ttles.ctx).Infof("Starting cached object TTL expiration scheduler...") ttles.stopped = false // Start timer for each deserialized entry for _, entry := range ttles.entries { entry.timer = ttles.startTimer(entry, entry.Expiry.Sub(time.Now())) } // Start a ticker to periodically save the entries index go func() { for { select { case <-ttles.saveTimer.C: ttles.Lock() if !ttles.indexDirty { ttles.Unlock() continue } err := ttles.writeState() if err != nil { dcontext.GetLogger(ttles.ctx).Errorf("Error writing scheduler state: %s", err) } else { ttles.indexDirty = false } ttles.Unlock() case <-ttles.doneChan: return } } }() return nil } func (ttles *TTLExpirationScheduler) add(r reference.Reference, ttl time.Duration, eType int) { entry := &schedulerEntry{ Key: r.String(), Expiry: time.Now().Add(ttl), EntryType: eType, } dcontext.GetLogger(ttles.ctx).Infof("Adding new scheduler entry for %s with ttl=%s", entry.Key, entry.Expiry.Sub(time.Now())) if oldEntry, present := ttles.entries[entry.Key]; present && oldEntry.timer != nil { oldEntry.timer.Stop() } ttles.entries[entry.Key] = entry entry.timer = ttles.startTimer(entry, ttl) ttles.indexDirty = true } func (ttles *TTLExpirationScheduler) startTimer(entry *schedulerEntry, ttl time.Duration) *time.Timer { return time.AfterFunc(ttl, func() { ttles.Lock() defer ttles.Unlock() var f expiryFunc switch entry.EntryType { case entryTypeBlob: f = ttles.onBlobExpire case entryTypeManifest: f = ttles.onManifestExpire default: f = func(reference.Reference) error { return fmt.Errorf("scheduler entry type") } } ref, err := reference.Parse(entry.Key) if err == nil { if err := f(ref); err != nil { dcontext.GetLogger(ttles.ctx).Errorf("Scheduler error returned from OnExpire(%s): %s", entry.Key, err) } } else { dcontext.GetLogger(ttles.ctx).Errorf("Error unpacking reference: %s", err) } delete(ttles.entries, entry.Key) ttles.indexDirty = true }) } // Stop stops the scheduler. func (ttles *TTLExpirationScheduler) Stop() { ttles.Lock() defer ttles.Unlock() if err := ttles.writeState(); err != nil { dcontext.GetLogger(ttles.ctx).Errorf("Error writing scheduler state: %s", err) } for _, entry := range ttles.entries { entry.timer.Stop() } close(ttles.doneChan) ttles.saveTimer.Stop() ttles.stopped = true } func (ttles *TTLExpirationScheduler) writeState() error { jsonBytes, err := json.Marshal(ttles.entries) if err != nil { return err } err = ttles.driver.PutContent(ttles.ctx, ttles.pathToStateFile, jsonBytes) if err != nil { return err } return nil } func (ttles *TTLExpirationScheduler) readState() error { if _, err := ttles.driver.Stat(ttles.ctx, ttles.pathToStateFile); err != nil { switch err := err.(type) { case driver.PathNotFoundError: return nil default: return err } } bytes, err := ttles.driver.GetContent(ttles.ctx, ttles.pathToStateFile) if err != nil { return err } err = json.Unmarshal(bytes, &ttles.entries) if err != nil { return err } return nil }