khenaidoo | 59ce9dd | 2019-11-11 13:05:32 -0500 | [diff] [blame^] | 1 | // Copyright 2017 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package v2v3 |
| 16 | |
| 17 | import ( |
| 18 | "context" |
| 19 | "strings" |
| 20 | |
| 21 | "go.etcd.io/etcd/clientv3" |
| 22 | "go.etcd.io/etcd/etcdserver/api/v2error" |
| 23 | "go.etcd.io/etcd/etcdserver/api/v2store" |
| 24 | ) |
| 25 | |
| 26 | func (s *v2v3Store) Watch(prefix string, recursive, stream bool, sinceIndex uint64) (v2store.Watcher, error) { |
| 27 | ctx, cancel := context.WithCancel(s.ctx) |
| 28 | wch := s.c.Watch( |
| 29 | ctx, |
| 30 | // TODO: very pricey; use a single store-wide watch in future |
| 31 | s.pfx, |
| 32 | clientv3.WithPrefix(), |
| 33 | clientv3.WithRev(int64(sinceIndex)), |
| 34 | clientv3.WithCreatedNotify(), |
| 35 | clientv3.WithPrevKV()) |
| 36 | resp, ok := <-wch |
| 37 | if err := resp.Err(); err != nil || !ok { |
| 38 | cancel() |
| 39 | return nil, v2error.NewError(v2error.EcodeRaftInternal, prefix, 0) |
| 40 | } |
| 41 | |
| 42 | evc, donec := make(chan *v2store.Event), make(chan struct{}) |
| 43 | go func() { |
| 44 | defer func() { |
| 45 | close(evc) |
| 46 | close(donec) |
| 47 | }() |
| 48 | for resp := range wch { |
| 49 | for _, ev := range s.mkV2Events(resp) { |
| 50 | k := ev.Node.Key |
| 51 | if recursive { |
| 52 | if !strings.HasPrefix(k, prefix) { |
| 53 | continue |
| 54 | } |
| 55 | // accept events on hidden keys given in prefix |
| 56 | k = strings.Replace(k, prefix, "/", 1) |
| 57 | // ignore hidden keys deeper than prefix |
| 58 | if strings.Contains(k, "/_") { |
| 59 | continue |
| 60 | } |
| 61 | } |
| 62 | if !recursive && k != prefix { |
| 63 | continue |
| 64 | } |
| 65 | select { |
| 66 | case evc <- ev: |
| 67 | case <-ctx.Done(): |
| 68 | return |
| 69 | } |
| 70 | if !stream { |
| 71 | return |
| 72 | } |
| 73 | } |
| 74 | } |
| 75 | }() |
| 76 | |
| 77 | return &v2v3Watcher{ |
| 78 | startRev: resp.Header.Revision, |
| 79 | evc: evc, |
| 80 | donec: donec, |
| 81 | cancel: cancel, |
| 82 | }, nil |
| 83 | } |
| 84 | |
| 85 | func (s *v2v3Store) mkV2Events(wr clientv3.WatchResponse) (evs []*v2store.Event) { |
| 86 | ak := s.mkActionKey() |
| 87 | for _, rev := range mkRevs(wr) { |
| 88 | var act, key *clientv3.Event |
| 89 | for _, ev := range rev { |
| 90 | if string(ev.Kv.Key) == ak { |
| 91 | act = ev |
| 92 | } else if key != nil && len(key.Kv.Key) < len(ev.Kv.Key) { |
| 93 | // use longest key to ignore intermediate new |
| 94 | // directories from Create. |
| 95 | key = ev |
| 96 | } else if key == nil { |
| 97 | key = ev |
| 98 | } |
| 99 | } |
| 100 | v2ev := &v2store.Event{ |
| 101 | Action: string(act.Kv.Value), |
| 102 | Node: s.mkV2Node(key.Kv), |
| 103 | PrevNode: s.mkV2Node(key.PrevKv), |
| 104 | EtcdIndex: mkV2Rev(wr.Header.Revision), |
| 105 | } |
| 106 | evs = append(evs, v2ev) |
| 107 | } |
| 108 | return evs |
| 109 | } |
| 110 | |
| 111 | func mkRevs(wr clientv3.WatchResponse) (revs [][]*clientv3.Event) { |
| 112 | var curRev []*clientv3.Event |
| 113 | for _, ev := range wr.Events { |
| 114 | if curRev != nil && ev.Kv.ModRevision != curRev[0].Kv.ModRevision { |
| 115 | revs = append(revs, curRev) |
| 116 | curRev = nil |
| 117 | } |
| 118 | curRev = append(curRev, ev) |
| 119 | } |
| 120 | if curRev != nil { |
| 121 | revs = append(revs, curRev) |
| 122 | } |
| 123 | return revs |
| 124 | } |
| 125 | |
| 126 | type v2v3Watcher struct { |
| 127 | startRev int64 |
| 128 | evc chan *v2store.Event |
| 129 | donec chan struct{} |
| 130 | cancel context.CancelFunc |
| 131 | } |
| 132 | |
| 133 | func (w *v2v3Watcher) StartIndex() uint64 { return mkV2Rev(w.startRev) } |
| 134 | |
| 135 | func (w *v2v3Watcher) Remove() { |
| 136 | w.cancel() |
| 137 | <-w.donec |
| 138 | } |
| 139 | |
| 140 | func (w *v2v3Watcher) EventChan() chan *v2store.Event { return w.evc } |