VOL-1967 move api-server to separate repository
Change-Id: I21b85be74205805be15f8a85e53a903d16785671
diff --git a/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go b/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
index 0135341..306470b 100644
--- a/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
+++ b/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
@@ -16,6 +16,7 @@
import (
"context"
+ "errors"
"fmt"
"sync"
@@ -23,6 +24,9 @@
pb "go.etcd.io/etcd/etcdserver/etcdserverpb"
)
+// ErrLocked is returned by TryLock when Mutex is already locked by another session.
+var ErrLocked = errors.New("mutex: Locked by another session")
+
// Mutex implements the sync Locker interface with etcd
type Mutex struct {
s *Session
@@ -37,9 +41,56 @@
return &Mutex{s, pfx + "/", "", -1, nil}
}
+// TryLock locks the mutex if not already locked by another session.
+// If lock is held by another session, return immediately after attempting necessary cleanup
+// The ctx argument is used for the sending/receiving Txn RPC.
+func (m *Mutex) TryLock(ctx context.Context) error {
+ resp, err := m.tryAcquire(ctx)
+ if err != nil {
+ return err
+ }
+ // if no key on prefix / the minimum rev is key, already hold the lock
+ ownerKey := resp.Responses[1].GetResponseRange().Kvs
+ if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
+ m.hdr = resp.Header
+ return nil
+ }
+ client := m.s.Client()
+ // Cannot lock, so delete the key
+ if _, err := client.Delete(ctx, m.myKey); err != nil {
+ return err
+ }
+ m.myKey = "\x00"
+ m.myRev = -1
+ return ErrLocked
+}
+
// Lock locks the mutex with a cancelable context. If the context is canceled
// while trying to acquire the lock, the mutex tries to clean its stale lock entry.
func (m *Mutex) Lock(ctx context.Context) error {
+ resp, err := m.tryAcquire(ctx)
+ if err != nil {
+ return err
+ }
+ // if no key on prefix / the minimum rev is key, already hold the lock
+ ownerKey := resp.Responses[1].GetResponseRange().Kvs
+ if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
+ m.hdr = resp.Header
+ return nil
+ }
+ client := m.s.Client()
+ // wait for deletion revisions prior to myKey
+ hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
+ // release lock key if wait failed
+ if werr != nil {
+ m.Unlock(client.Ctx())
+ } else {
+ m.hdr = hdr
+ }
+ return werr
+}
+
+func (m *Mutex) tryAcquire(ctx context.Context) (*v3.TxnResponse, error) {
s := m.s
client := m.s.Client()
@@ -53,28 +104,13 @@
getOwner := v3.OpGet(m.pfx, v3.WithFirstCreate()...)
resp, err := client.Txn(ctx).If(cmp).Then(put, getOwner).Else(get, getOwner).Commit()
if err != nil {
- return err
+ return nil, err
}
m.myRev = resp.Header.Revision
if !resp.Succeeded {
m.myRev = resp.Responses[0].GetResponseRange().Kvs[0].CreateRevision
}
- // if no key on prefix / the minimum rev is key, already hold the lock
- ownerKey := resp.Responses[1].GetResponseRange().Kvs
- if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
- m.hdr = resp.Header
- return nil
- }
-
- // wait for deletion revisions prior to myKey
- hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
- // release lock key if wait failed
- if werr != nil {
- m.Unlock(client.Ctx())
- } else {
- m.hdr = hdr
- }
- return werr
+ return resp, nil
}
func (m *Mutex) Unlock(ctx context.Context) error {