[VOL-2538] Logging - Implement dynamic log levels in ofagent
Change-Id: I9582230d9d3c34ea84339fddf2b2f3b3d2804808
diff --git a/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go b/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
new file mode 100644
index 0000000..306470b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
@@ -0,0 +1,153 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package concurrency
+
+import (
+ "context"
+ "errors"
+ "fmt"
+ "sync"
+
+ v3 "go.etcd.io/etcd/clientv3"
+ 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
+
+ pfx string
+ myKey string
+ myRev int64
+ hdr *pb.ResponseHeader
+}
+
+func NewMutex(s *Session, pfx string) *Mutex {
+ 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()
+
+ m.myKey = fmt.Sprintf("%s%x", m.pfx, s.Lease())
+ cmp := v3.Compare(v3.CreateRevision(m.myKey), "=", 0)
+ // put self in lock waiters via myKey; oldest waiter holds lock
+ put := v3.OpPut(m.myKey, "", v3.WithLease(s.Lease()))
+ // reuse key in case this session already holds the lock
+ get := v3.OpGet(m.myKey)
+ // fetch current holder to complete uncontended path with only one RPC
+ 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 nil, err
+ }
+ m.myRev = resp.Header.Revision
+ if !resp.Succeeded {
+ m.myRev = resp.Responses[0].GetResponseRange().Kvs[0].CreateRevision
+ }
+ return resp, nil
+}
+
+func (m *Mutex) Unlock(ctx context.Context) error {
+ client := m.s.Client()
+ if _, err := client.Delete(ctx, m.myKey); err != nil {
+ return err
+ }
+ m.myKey = "\x00"
+ m.myRev = -1
+ return nil
+}
+
+func (m *Mutex) IsOwner() v3.Cmp {
+ return v3.Compare(v3.CreateRevision(m.myKey), "=", m.myRev)
+}
+
+func (m *Mutex) Key() string { return m.myKey }
+
+// Header is the response header received from etcd on acquiring the lock.
+func (m *Mutex) Header() *pb.ResponseHeader { return m.hdr }
+
+type lockerMutex struct{ *Mutex }
+
+func (lm *lockerMutex) Lock() {
+ client := lm.s.Client()
+ if err := lm.Mutex.Lock(client.Ctx()); err != nil {
+ panic(err)
+ }
+}
+func (lm *lockerMutex) Unlock() {
+ client := lm.s.Client()
+ if err := lm.Mutex.Unlock(client.Ctx()); err != nil {
+ panic(err)
+ }
+}
+
+// NewLocker creates a sync.Locker backed by an etcd mutex.
+func NewLocker(s *Session, pfx string) sync.Locker {
+ return &lockerMutex{NewMutex(s, pfx)}
+}