mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
131 lines
3.2 KiB
Go
131 lines
3.2 KiB
Go
// Copyright 2016 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package grpcproxy
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import (
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"time"
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pb "go.etcd.io/etcd/api/v3/etcdserverpb"
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"go.etcd.io/etcd/api/v3/mvccpb"
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clientv3 "go.etcd.io/etcd/client/v3"
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"go.etcd.io/etcd/server/v3/storage/mvcc"
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)
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type watchRange struct {
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key, end string
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}
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func (wr *watchRange) valid() bool {
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return len(wr.end) == 0 || wr.end > wr.key || (wr.end[0] == 0 && len(wr.end) == 1)
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}
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type watcher struct {
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// user configuration
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wr watchRange
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filters []mvcc.FilterFunc
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progress bool
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prevKV bool
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// id is the id returned to the client on its watch stream.
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id int64
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// nextrev is the minimum expected next event revision.
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nextrev int64
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// lastHeader has the last header sent over the stream.
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lastHeader pb.ResponseHeader
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// wps is the parent.
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wps *watchProxyStream
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}
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// send filters out repeated events by discarding revisions older
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// than the last one sent over the watch channel.
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func (w *watcher) send(wr clientv3.WatchResponse) {
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if wr.IsProgressNotify() && !w.progress {
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return
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}
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if w.nextrev > wr.Header.Revision && len(wr.Events) > 0 {
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return
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}
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if w.nextrev == 0 {
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// current watch; expect updates following this revision
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w.nextrev = wr.Header.Revision + 1
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}
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events := make([]*mvccpb.Event, 0, len(wr.Events))
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var lastRev int64
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for i := range wr.Events {
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ev := (*mvccpb.Event)(wr.Events[i])
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if ev.Kv.ModRevision < w.nextrev {
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continue
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} else {
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// We cannot update w.rev here.
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// txn can have multiple events with the same rev.
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// If w.nextrev updates here, it would skip events in the same txn.
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lastRev = ev.Kv.ModRevision
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}
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filtered := false
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for _, filter := range w.filters {
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if filter(*ev) {
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filtered = true
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break
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}
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}
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if filtered {
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continue
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}
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if !w.prevKV {
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evCopy := *ev
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evCopy.PrevKv = nil
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ev = &evCopy
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}
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events = append(events, ev)
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}
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if lastRev >= w.nextrev {
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w.nextrev = lastRev + 1
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}
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// all events are filtered out?
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if !wr.IsProgressNotify() && !wr.Created && len(events) == 0 && wr.CompactRevision == 0 {
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return
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}
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w.lastHeader = wr.Header
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w.post(&pb.WatchResponse{
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Header: &wr.Header,
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Created: wr.Created,
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CompactRevision: wr.CompactRevision,
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Canceled: wr.Canceled,
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WatchId: w.id,
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Events: events,
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})
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}
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// post puts a watch response on the watcher's proxy stream channel
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func (w *watcher) post(wr *pb.WatchResponse) bool {
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select {
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case w.wps.watchCh <- wr:
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case <-time.After(50 * time.Millisecond):
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w.wps.cancel()
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w.wps.lg.Error("failed to put a watch response on the watcher's proxy stream channel,err is timeout")
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return false
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}
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return true
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}
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