go.etcd.io/etcd@v3.3.27+incompatible/clientv3/clientv3util/util.go (about)

     1  // Copyright 2017 The etcd Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package clientv3util contains utility functions derived from clientv3.
    16  package clientv3util
    17  
    18  import (
    19  	"github.com/coreos/etcd/clientv3"
    20  )
    21  
    22  // KeyExists returns a comparison operation that evaluates to true iff the given
    23  // key exists. It does this by checking if the key `Version` is greater than 0.
    24  // It is a useful guard in transaction delete operations.
    25  func KeyExists(key string) clientv3.Cmp {
    26  	return clientv3.Compare(clientv3.Version(key), ">", 0)
    27  }
    28  
    29  // KeyMissing returns a comparison operation that evaluates to true iff the
    30  // given key does not exist.
    31  func KeyMissing(key string) clientv3.Cmp {
    32  	return clientv3.Compare(clientv3.Version(key), "=", 0)
    33  }