51b4d6b7a8
We do not wait for the cancellation from actual etcd server, but generate it at the proxy side. The rule is to return the latest rev that the watcher has seen. This should be good enough for most use cases if not all.
100 lines
2.1 KiB
Go
100 lines
2.1 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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"sync"
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"golang.org/x/net/context"
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"github.com/coreos/etcd/clientv3"
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)
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type watcherGroup struct {
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// ch delievers events received from the etcd server
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ch clientv3.WatchChan
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// cancel is used to cancel the underlying etcd server watcher
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// It should also close the ch.
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cancel context.CancelFunc
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mu sync.Mutex
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rev int64 // current revision of the watchergroup
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receivers map[receiverID]watcher
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donec chan struct{}
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}
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type receiverID struct {
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streamID, watcherID int64
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}
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func newWatchergroup(wch clientv3.WatchChan, c context.CancelFunc) *watcherGroup {
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return &watcherGroup{
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ch: wch,
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cancel: c,
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receivers: make(map[receiverID]watcher),
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donec: make(chan struct{}),
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}
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}
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func (wg *watcherGroup) run() {
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defer close(wg.donec)
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for wr := range wg.ch {
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wg.broadcast(wr)
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}
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}
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func (wg *watcherGroup) broadcast(wr clientv3.WatchResponse) {
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wg.mu.Lock()
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defer wg.mu.Unlock()
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wg.rev = wr.Header.Revision
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for _, r := range wg.receivers {
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r.send(wr)
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}
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}
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func (wg *watcherGroup) add(rid receiverID, w watcher) {
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wg.mu.Lock()
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defer wg.mu.Unlock()
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wg.receivers[rid] = w
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}
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func (wg *watcherGroup) delete(rid receiverID) {
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wg.mu.Lock()
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defer wg.mu.Unlock()
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delete(wg.receivers, rid)
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}
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func (wg *watcherGroup) isEmpty() bool {
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wg.mu.Lock()
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defer wg.mu.Unlock()
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return len(wg.receivers) == 0
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}
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func (wg *watcherGroup) stop() {
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wg.cancel()
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<-wg.donec
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}
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func (wg *watcherGroup) revision() int64 {
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wg.mu.Lock()
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defer wg.mu.Unlock()
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return wg.rev
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}
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