mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
56 lines
1.6 KiB
Go
56 lines
1.6 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 recipe
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import (
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"context"
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"errors"
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v3 "go.etcd.io/etcd/clientv3"
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spb "go.etcd.io/etcd/mvcc/mvccpb"
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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(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(context.TODO()).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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func claimFirstKey(kv v3.KV, kvs []*spb.KeyValue) (*spb.KeyValue, error) {
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for _, k := range kvs {
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ok, err := deleteRevKey(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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