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// Copyright 2017 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 v2v3
import (
"context"
"strings"
"go.etcd.io/etcd/client/v3"
"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
)
func (s *v2v3Store) Watch(prefix string, recursive, stream bool, sinceIndex uint64) (v2store.Watcher, error) {
ctx, cancel := context.WithCancel(s.ctx)
wch := s.c.Watch(
ctx,
// TODO: very pricey; use a single store-wide watch in future
s.pfx,
clientv3.WithPrefix(),
clientv3.WithRev(int64(sinceIndex)),
clientv3.WithCreatedNotify(),
clientv3.WithPrevKV())
resp, ok := <-wch
if err := resp.Err(); err != nil || !ok {
cancel()
return nil, v2error.NewError(v2error.EcodeRaftInternal, prefix, 0)
}
evc, donec := make(chan *v2store.Event), make(chan struct{})
go func() {
defer func() {
close(evc)
close(donec)
}()
for resp := range wch {
for _, ev := range s.mkV2Events(resp) {
k := ev.Node.Key
if recursive {
if !strings.HasPrefix(k, prefix) {
continue
}
// accept events on hidden keys given in prefix
k = strings.Replace(k, prefix, "/", 1)
// ignore hidden keys deeper than prefix
if strings.Contains(k, "/_") {
continue
}
}
if !recursive && k != prefix {
continue
}
select {
case evc <- ev:
case <-ctx.Done():
return
}
if !stream {
return
}
}
}
}()
return &v2v3Watcher{
startRev: resp.Header.Revision,
evc: evc,
donec: donec,
cancel: cancel,
}, nil
}
func (s *v2v3Store) mkV2Events(wr clientv3.WatchResponse) (evs []*v2store.Event) {
ak := s.mkActionKey()
for _, rev := range mkRevs(wr) {
var act, key *clientv3.Event
for _, ev := range rev {
if string(ev.Kv.Key) == ak {
act = ev
} else if key != nil && len(key.Kv.Key) < len(ev.Kv.Key) {
// use longest key to ignore intermediate new
// directories from Create.
key = ev
} else if key == nil {
key = ev
}
}
if act != nil && act.Kv != nil && key != nil {
v2ev := &v2store.Event{
Action: string(act.Kv.Value),
Node: s.mkV2Node(key.Kv),
PrevNode: s.mkV2Node(key.PrevKv),
EtcdIndex: mkV2Rev(wr.Header.Revision),
}
evs = append(evs, v2ev)
}
}
return evs
}
func mkRevs(wr clientv3.WatchResponse) (revs [][]*clientv3.Event) {
var curRev []*clientv3.Event
for _, ev := range wr.Events {
if curRev != nil && ev.Kv.ModRevision != curRev[0].Kv.ModRevision {
revs = append(revs, curRev)
curRev = nil
}
curRev = append(curRev, ev)
}
if curRev != nil {
revs = append(revs, curRev)
}
return revs
}
type v2v3Watcher struct {
startRev int64
evc chan *v2store.Event
donec chan struct{}
cancel context.CancelFunc
}
func (w *v2v3Watcher) StartIndex() uint64 { return mkV2Rev(w.startRev) }
func (w *v2v3Watcher) Remove() {
w.cancel()
<-w.donec
}
func (w *v2v3Watcher) EventChan() chan *v2store.Event { return w.evc }
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