2018-03-14 14:12:26 +08:00
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// Copyright (C) 2014-2018 Goodrain Co., Ltd.
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2017-11-07 11:40:44 +08:00
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// RAINBOND, Application Management Platform
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2018-03-14 14:33:31 +08:00
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2017-11-07 11:40:44 +08:00
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version. For any non-GPL usage of Rainbond,
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// one or multiple Commercial Licenses authorized by Goodrain Co., Ltd.
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// must be obtained first.
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2018-03-14 14:33:31 +08:00
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2017-11-07 11:40:44 +08:00
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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2018-03-14 14:33:31 +08:00
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2017-11-07 11:40:44 +08:00
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package etcd
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import (
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"errors"
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v3 "github.com/coreos/etcd/clientv3"
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spb "github.com/coreos/etcd/mvcc/mvccpb"
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"golang.org/x/net/context"
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)
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var (
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ErrKeyExists = errors.New("key already exists")
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ErrWaitMismatch = errors.New("unexpected wait result")
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ErrTooManyClients = errors.New("too many clients")
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ErrNoWatcher = errors.New("no watcher channel")
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)
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// deleteRevKey deletes a key by revision, returning false if key is missing
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func deleteRevKey(ctx context.Context, kv v3.KV, key string, rev int64) (bool, error) {
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cmp := v3.Compare(v3.ModRevision(key), "=", rev)
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req := v3.OpDelete(key)
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txnresp, err := kv.Txn(ctx).If(cmp).Then(req).Commit()
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if err != nil {
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return false, err
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} else if !txnresp.Succeeded {
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return false, nil
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}
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return true, nil
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}
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//claimFirstKey 获取队列第一个key,并从队列删除
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func claimFirstKey(ctx context.Context, kv v3.KV, kvs []*spb.KeyValue) (*spb.KeyValue, error) {
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for _, k := range kvs {
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ok, err := deleteRevKey(ctx, kv, string(k.Key), k.ModRevision)
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if err != nil {
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return nil, err
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} else if ok {
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return k, nil
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}
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}
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return nil, nil
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}
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