mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
114 lines
3.0 KiB
Go
114 lines
3.0 KiB
Go
// Copyright 2016 CoreOS, Inc.
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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 recipe
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import (
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"sync"
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"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
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"github.com/coreos/etcd/clientv3"
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"github.com/coreos/etcd/lease"
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)
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// only keep one ephemeral lease per client
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var clientLeases clientLeaseMgr = clientLeaseMgr{leases: make(map[*clientv3.Client]*leaseKeepAlive)}
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type clientLeaseMgr struct {
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leases map[*clientv3.Client]*leaseKeepAlive
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mu sync.Mutex
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}
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type leaseKeepAlive struct {
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id lease.LeaseID
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cancel context.CancelFunc
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donec <-chan struct{}
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}
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func SessionLease(client *clientv3.Client) (lease.LeaseID, error) {
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return clientLeases.sessionLease(client, 120)
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}
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func SessionLeaseTTL(client *clientv3.Client, ttl int64) (lease.LeaseID, error) {
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return clientLeases.sessionLease(client, ttl)
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}
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// StopSessionLease ends the refresh for the session lease. This is useful
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// in case the state of the client connection is indeterminate (revoke
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// would fail) or if transferring lease ownership.
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func StopSessionLease(client *clientv3.Client) {
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clientLeases.mu.Lock()
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lka := clientLeases.leases[client]
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clientLeases.mu.Unlock()
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if lka != nil {
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lka.cancel()
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<-lka.donec
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}
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}
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// RevokeSessionLease revokes the session lease.
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func RevokeSessionLease(client *clientv3.Client) (err error) {
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clientLeases.mu.Lock()
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lka := clientLeases.leases[client]
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clientLeases.mu.Unlock()
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StopSessionLease(client)
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if lka != nil {
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_, err = clientv3.NewLease(client).Revoke(context.TODO(), lka.id)
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}
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return err
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}
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func (clm *clientLeaseMgr) sessionLease(client *clientv3.Client, ttl int64) (lease.LeaseID, error) {
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clm.mu.Lock()
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defer clm.mu.Unlock()
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if lka, ok := clm.leases[client]; ok {
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return lka.id, nil
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}
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lc := clientv3.NewLease(client)
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resp, err := lc.Create(context.TODO(), ttl)
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if err != nil {
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return lease.NoLease, err
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}
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id := lease.LeaseID(resp.ID)
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ctx, cancel := context.WithCancel(context.Background())
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keepAlive, err := lc.KeepAlive(ctx, id)
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if err != nil || keepAlive == nil {
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return lease.NoLease, err
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}
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donec := make(chan struct{})
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lka := &leaseKeepAlive{
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id: id,
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cancel: cancel,
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donec: donec}
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clm.leases[client] = lka
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// keep the lease alive until client error or cancelled context
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go func() {
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defer func() {
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clm.mu.Lock()
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delete(clm.leases, client)
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clm.mu.Unlock()
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lc.Close()
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close(donec)
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}()
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for range keepAlive {
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// eat messages until keep alive channel closes
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}
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}()
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return id, nil
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}
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