distribution/registry/proxy/scheduler/scheduler.go

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package scheduler
import (
"encoding/json"
"fmt"
"sync"
"time"
"github.com/docker/distribution/context"
"github.com/docker/distribution/registry/storage/driver"
)
// onTTLExpiryFunc is called when a repository's TTL expires
type expiryFunc func(string) error
const (
entryTypeBlob = iota
entryTypeManifest
)
// 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,
}
}
// 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
}
// 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(dgst string, ttl time.Duration) error {
ttles.Lock()
defer ttles.Unlock()
if ttles.stopped {
return fmt.Errorf("scheduler not started")
}
ttles.add(dgst, ttl, entryTypeBlob)
return nil
}
// AddManifest schedules a manifest cleanup after ttl expires
func (ttles *TTLExpirationScheduler) AddManifest(repoName string, ttl time.Duration) error {
ttles.Lock()
defer ttles.Unlock()
if ttles.stopped {
return fmt.Errorf("scheduler not started")
}
ttles.add(repoName, 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")
}
context.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()))
}
return nil
}
func (ttles *TTLExpirationScheduler) add(key string, ttl time.Duration, eType int) {
entry := &schedulerEntry{
Key: key,
Expiry: time.Now().Add(ttl),
EntryType: eType,
}
context.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[key]; present && oldEntry.timer != nil {
oldEntry.timer.Stop()
}
ttles.entries[key] = entry
entry.timer = ttles.startTimer(entry, ttl)
if err := ttles.writeState(); err != nil {
context.GetLogger(ttles.ctx).Errorf("Error writing scheduler state: %s", err)
}
}
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(repoName string) error {
return fmt.Errorf("Unexpected scheduler entry type")
}
}
if err := f(entry.Key); err != nil {
context.GetLogger(ttles.ctx).Errorf("Scheduler error returned from OnExpire(%s): %s", entry.Key, err)
}
delete(ttles.entries, entry.Key)
if err := ttles.writeState(); err != nil {
context.GetLogger(ttles.ctx).Errorf("Error writing scheduler state: %s", err)
}
})
}
// Stop stops the scheduler.
func (ttles *TTLExpirationScheduler) Stop() {
ttles.Lock()
defer ttles.Unlock()
if err := ttles.writeState(); err != nil {
context.GetLogger(ttles.ctx).Errorf("Error writing scheduler state: %s", err)
}
for _, entry := range ttles.entries {
entry.timer.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
}