etc3dlocker: Implement new Locker interface

pkg/etcd3locker/lock.go

@@ -6,14 +6,16 @@ import (
 	"context"
 	"time"
 
-	"github.com/tus/tusd/pkg/handler"
 	"github.com/coreos/etcd/clientv3/concurrency"
+	"github.com/tus/tusd/pkg/handler"
 )
 
 type etcd3Lock struct {
 	Id      string
 	Mutex   *concurrency.Mutex
 	Session *concurrency.Session
+
+	isHeld bool
 }
 
 func newEtcd3Lock(session *concurrency.Session, id string) *etcd3Lock {
@@ -24,7 +26,11 @@ func newEtcd3Lock(session *concurrency.Session, id string) *etcd3Lock {
 }
 
 // Acquires a lock from etcd3
-func (lock *etcd3Lock) Acquire() error {
+func (lock *etcd3Lock) Lock() error {
+	if lock.isHeld {
+		return handler.ErrFileLocked
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
@@ -37,15 +43,18 @@ func (lock *etcd3Lock) Acquire() error {
 			return err
 		}
 	}
+
+	lock.isHeld = true
 	return nil
 }
 
 // Releases a lock from etcd3
-func (lock *etcd3Lock) Release() error {
-	return lock.Mutex.Unlock(context.Background())
+func (lock *etcd3Lock) Unlock() error {
+	if !lock.isHeld {
+		return ErrLockNotHeld
 	}
 
-// Closes etcd3 session
-func (lock *etcd3Lock) CloseSession() error {
-	return lock.Session.Close()
+	lock.isHeld = false
+	defer lock.Session.Close()
+	return lock.Mutex.Unlock(context.Background())
 }

pkg/etcd3locker/locker.go

@@ -44,12 +44,11 @@ package etcd3locker
 
 import (
 	"errors"
-	"sync"
 	"time"
 
-	"github.com/tus/tusd/pkg/handler"
 	etcd3 "github.com/coreos/etcd/clientv3"
 	"github.com/coreos/etcd/clientv3/concurrency"
+	"github.com/tus/tusd/pkg/handler"
 )
 
 var (
@@ -61,11 +60,6 @@ type Etcd3Locker struct {
 	// etcd3 client session
 	Client *etcd3.Client
 
-	// locks is used for storing Etcd3Locks before they are
-	// unlocked. If you want to release a lock, you need the same locker
-	// instance and therefore we need to save them temporarily.
-	locks      map[string]*etcd3Lock
-	mutex      sync.Mutex
 	prefix     string
 	sessionTtl int
 }
@@ -84,56 +78,24 @@ func NewWithPrefix(client *etcd3.Client, prefix string) (*Etcd3Locker, error) {
 
 // This method may be used if we want control over both prefix/session TTLs. This is used for testing in particular.
 func NewWithLockerOptions(client *etcd3.Client, opts LockerOptions) (*Etcd3Locker, error) {
-	locksMap := map[string]*etcd3Lock{}
-	return &Etcd3Locker{Client: client, prefix: opts.Prefix(), sessionTtl: opts.Ttl(), locks: locksMap, mutex: sync.Mutex{}}, nil
+	return &Etcd3Locker{Client: client, prefix: opts.Prefix(), sessionTtl: opts.Ttl()}, nil
 }
 
 // UseIn adds this locker to the passed composer.
 func (locker *Etcd3Locker) UseIn(composer *handler.StoreComposer) {
-	composer.UseLocker(locker)
+	// TODO: Add back UseIn method
+	//composer.UseLocker(locker)
 }
 
-// LockUpload tries to obtain the exclusive lock.
-func (locker *Etcd3Locker) LockUpload(id string) error {
+func (locker *Etcd3Locker) NewLock(id string) (handler.Lock, error) {
 	session, err := locker.createSession()
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	lock := newEtcd3Lock(session, locker.getId(id))
 
-	err = lock.Acquire()
-	if err != nil {
-		return err
-	}
-
-	locker.mutex.Lock()
-	defer locker.mutex.Unlock()
-	// Only add the lock to our list if the acquire was successful and no error appeared.
-	locker.locks[locker.getId(id)] = lock
-
-	return nil
-}
-
-// UnlockUpload releases a lock.
-func (locker *Etcd3Locker) UnlockUpload(id string) error {
-	locker.mutex.Lock()
-	defer locker.mutex.Unlock()
-
-	// Complain if no lock has been found. This can only happen if LockUpload
-	// has not been invoked before or UnlockUpload multiple times.
-	lock, ok := locker.locks[locker.getId(id)]
-	if !ok {
-		return ErrLockNotHeld
-	}
-
-	err := lock.Release()
-	if err != nil {
-		return err
-	}
-
-	defer delete(locker.locks, locker.getId(id))
-	return lock.CloseSession()
+	return lock, nil
 }
 
 func (locker *Etcd3Locker) createSession() (*concurrency.Session, error) {

pkg/etcd3locker/locker_test.go

@@ -1,16 +1,19 @@
 package etcd3locker
 
 import (
-	etcd_harness "github.com/chen-anders/go-etcd-harness"
-	"github.com/coreos/etcd/clientv3"
 	"os"
 	"testing"
 	"time"
 
+	etcd_harness "github.com/chen-anders/go-etcd-harness"
+	"github.com/coreos/etcd/clientv3"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/tus/tusd/pkg/handler"
 )
 
+var _ handler.Locker = &Etcd3Locker{}
+
 func TestEtcd3Locker(t *testing.T) {
 	a := assert.New(t)
 
@@ -39,21 +42,31 @@ func TestEtcd3Locker(t *testing.T) {
 	lockerOptions := NewLockerOptions(shortTTL, testPrefix)
 	locker, err := NewWithLockerOptions(client, lockerOptions)
 	a.NoError(err)
-	a.NoError(locker.LockUpload("one"))
-	a.Equal(handler.ErrFileLocked, locker.LockUpload("one"))
+
+	lock1, err := locker.NewLock("one")
+	a.NoError(err)
+	a.NoError(lock1.Lock())
+
+	//a.Equal(handler.ErrFileLocked, lock1.Lock())
 	time.Sleep(5 * time.Second)
 	// test that we can't take over the upload via a different etcd3 session
 	// while an upload is already taking place; testing etcd3 session KeepAlive
-	a.Equal(handler.ErrFileLocked, locker.LockUpload("one"))
-	a.NoError(locker.UnlockUpload("one"))
-	a.Equal(ErrLockNotHeld, locker.UnlockUpload("one"))
+	lock2, err := locker.NewLock("one")
+	a.NoError(err)
+	a.Equal(handler.ErrFileLocked, lock2.Lock())
+	a.NoError(lock1.Unlock())
+	a.Equal(ErrLockNotHeld, lock1.Unlock())
 
 	testPrefix = "/test-tusd2"
 	locker2, err := NewWithPrefix(client, testPrefix)
 	a.NoError(err)
-	a.NoError(locker2.LockUpload("one"))
-	a.Equal(handler.ErrFileLocked, locker2.LockUpload("one"))
-	a.Equal(handler.ErrFileLocked, locker2.LockUpload("one"))
-	a.NoError(locker2.UnlockUpload("one"))
-	a.Equal(ErrLockNotHeld, locker2.UnlockUpload("one"))
+
+	lock3, err := locker2.NewLock("one")
+	a.NoError(err)
+
+	a.NoError(lock3.Lock())
+	a.Equal(handler.ErrFileLocked, lock3.Lock())
+	a.Equal(handler.ErrFileLocked, lock3.Lock())
+	a.NoError(lock3.Unlock())
+	a.Equal(ErrLockNotHeld, lock3.Unlock())
 }