[VOL-2538] Logging - Implement dynamic log levels in ofagent
Change-Id: I9582230d9d3c34ea84339fddf2b2f3b3d2804808
diff --git a/vendor/go.etcd.io/etcd/clientv3/concurrency/election.go b/vendor/go.etcd.io/etcd/clientv3/concurrency/election.go
new file mode 100644
index 0000000..2521db6
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/concurrency/election.go
@@ -0,0 +1,254 @@
+// 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"
+
+ v3 "go.etcd.io/etcd/clientv3"
+ pb "go.etcd.io/etcd/etcdserver/etcdserverpb"
+ "go.etcd.io/etcd/mvcc/mvccpb"
+)
+
+var (
+ ErrElectionNotLeader = errors.New("election: not leader")
+ ErrElectionNoLeader = errors.New("election: no leader")
+)
+
+type Election struct {
+ session *Session
+
+ keyPrefix string
+
+ leaderKey string
+ leaderRev int64
+ leaderSession *Session
+ hdr *pb.ResponseHeader
+}
+
+// NewElection returns a new election on a given key prefix.
+func NewElection(s *Session, pfx string) *Election {
+ return &Election{session: s, keyPrefix: pfx + "/"}
+}
+
+// ResumeElection initializes an election with a known leader.
+func ResumeElection(s *Session, pfx string, leaderKey string, leaderRev int64) *Election {
+ return &Election{
+ keyPrefix: pfx,
+ session: s,
+ leaderKey: leaderKey,
+ leaderRev: leaderRev,
+ leaderSession: s,
+ }
+}
+
+// Campaign puts a value as eligible for the election on the prefix
+// key.
+// Multiple sessions can participate in the election for the
+// same prefix, but only one can be the leader at a time.
+//
+// If the context is 'context.TODO()/context.Background()', the Campaign
+// will continue to be blocked for other keys to be deleted, unless server
+// returns a non-recoverable error (e.g. ErrCompacted).
+// Otherwise, until the context is not cancelled or timed-out, Campaign will
+// continue to be blocked until it becomes the leader.
+func (e *Election) Campaign(ctx context.Context, val string) error {
+ s := e.session
+ client := e.session.Client()
+
+ k := fmt.Sprintf("%s%x", e.keyPrefix, s.Lease())
+ txn := client.Txn(ctx).If(v3.Compare(v3.CreateRevision(k), "=", 0))
+ txn = txn.Then(v3.OpPut(k, val, v3.WithLease(s.Lease())))
+ txn = txn.Else(v3.OpGet(k))
+ resp, err := txn.Commit()
+ if err != nil {
+ return err
+ }
+ e.leaderKey, e.leaderRev, e.leaderSession = k, resp.Header.Revision, s
+ if !resp.Succeeded {
+ kv := resp.Responses[0].GetResponseRange().Kvs[0]
+ e.leaderRev = kv.CreateRevision
+ if string(kv.Value) != val {
+ if err = e.Proclaim(ctx, val); err != nil {
+ e.Resign(ctx)
+ return err
+ }
+ }
+ }
+
+ _, err = waitDeletes(ctx, client, e.keyPrefix, e.leaderRev-1)
+ if err != nil {
+ // clean up in case of context cancel
+ select {
+ case <-ctx.Done():
+ e.Resign(client.Ctx())
+ default:
+ e.leaderSession = nil
+ }
+ return err
+ }
+ e.hdr = resp.Header
+
+ return nil
+}
+
+// Proclaim lets the leader announce a new value without another election.
+func (e *Election) Proclaim(ctx context.Context, val string) error {
+ if e.leaderSession == nil {
+ return ErrElectionNotLeader
+ }
+ client := e.session.Client()
+ cmp := v3.Compare(v3.CreateRevision(e.leaderKey), "=", e.leaderRev)
+ txn := client.Txn(ctx).If(cmp)
+ txn = txn.Then(v3.OpPut(e.leaderKey, val, v3.WithLease(e.leaderSession.Lease())))
+ tresp, terr := txn.Commit()
+ if terr != nil {
+ return terr
+ }
+ if !tresp.Succeeded {
+ e.leaderKey = ""
+ return ErrElectionNotLeader
+ }
+
+ e.hdr = tresp.Header
+ return nil
+}
+
+// Resign lets a leader start a new election.
+func (e *Election) Resign(ctx context.Context) (err error) {
+ if e.leaderSession == nil {
+ return nil
+ }
+ client := e.session.Client()
+ cmp := v3.Compare(v3.CreateRevision(e.leaderKey), "=", e.leaderRev)
+ resp, err := client.Txn(ctx).If(cmp).Then(v3.OpDelete(e.leaderKey)).Commit()
+ if err == nil {
+ e.hdr = resp.Header
+ }
+ e.leaderKey = ""
+ e.leaderSession = nil
+ return err
+}
+
+// Leader returns the leader value for the current election.
+func (e *Election) Leader(ctx context.Context) (*v3.GetResponse, error) {
+ client := e.session.Client()
+ resp, err := client.Get(ctx, e.keyPrefix, v3.WithFirstCreate()...)
+ if err != nil {
+ return nil, err
+ } else if len(resp.Kvs) == 0 {
+ // no leader currently elected
+ return nil, ErrElectionNoLeader
+ }
+ return resp, nil
+}
+
+// Observe returns a channel that reliably observes ordered leader proposals
+// as GetResponse values on every current elected leader key. It will not
+// necessarily fetch all historical leader updates, but will always post the
+// most recent leader value.
+//
+// The channel closes when the context is canceled or the underlying watcher
+// is otherwise disrupted.
+func (e *Election) Observe(ctx context.Context) <-chan v3.GetResponse {
+ retc := make(chan v3.GetResponse)
+ go e.observe(ctx, retc)
+ return retc
+}
+
+func (e *Election) observe(ctx context.Context, ch chan<- v3.GetResponse) {
+ client := e.session.Client()
+
+ defer close(ch)
+ for {
+ resp, err := client.Get(ctx, e.keyPrefix, v3.WithFirstCreate()...)
+ if err != nil {
+ return
+ }
+
+ var kv *mvccpb.KeyValue
+ var hdr *pb.ResponseHeader
+
+ if len(resp.Kvs) == 0 {
+ cctx, cancel := context.WithCancel(ctx)
+ // wait for first key put on prefix
+ opts := []v3.OpOption{v3.WithRev(resp.Header.Revision), v3.WithPrefix()}
+ wch := client.Watch(cctx, e.keyPrefix, opts...)
+ for kv == nil {
+ wr, ok := <-wch
+ if !ok || wr.Err() != nil {
+ cancel()
+ return
+ }
+ // only accept puts; a delete will make observe() spin
+ for _, ev := range wr.Events {
+ if ev.Type == mvccpb.PUT {
+ hdr, kv = &wr.Header, ev.Kv
+ // may have multiple revs; hdr.rev = the last rev
+ // set to kv's rev in case batch has multiple Puts
+ hdr.Revision = kv.ModRevision
+ break
+ }
+ }
+ }
+ cancel()
+ } else {
+ hdr, kv = resp.Header, resp.Kvs[0]
+ }
+
+ select {
+ case ch <- v3.GetResponse{Header: hdr, Kvs: []*mvccpb.KeyValue{kv}}:
+ case <-ctx.Done():
+ return
+ }
+
+ cctx, cancel := context.WithCancel(ctx)
+ wch := client.Watch(cctx, string(kv.Key), v3.WithRev(hdr.Revision+1))
+ keyDeleted := false
+ for !keyDeleted {
+ wr, ok := <-wch
+ if !ok {
+ cancel()
+ return
+ }
+ for _, ev := range wr.Events {
+ if ev.Type == mvccpb.DELETE {
+ keyDeleted = true
+ break
+ }
+ resp.Header = &wr.Header
+ resp.Kvs = []*mvccpb.KeyValue{ev.Kv}
+ select {
+ case ch <- *resp:
+ case <-cctx.Done():
+ cancel()
+ return
+ }
+ }
+ }
+ cancel()
+ }
+}
+
+// Key returns the leader key if elected, empty string otherwise.
+func (e *Election) Key() string { return e.leaderKey }
+
+// Rev returns the leader key's creation revision, if elected.
+func (e *Election) Rev() int64 { return e.leaderRev }
+
+// Header is the response header from the last successful election proposal.
+func (e *Election) Header() *pb.ResponseHeader { return e.hdr }