k8s.io/apiserver@v0.31.1/pkg/storage/etcd3/event.go (about)

     1  /*
     2  Copyright 2016 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package etcd3
    18  
    19  import (
    20  	"fmt"
    21  	"go.etcd.io/etcd/api/v3/mvccpb"
    22  	clientv3 "go.etcd.io/etcd/client/v3"
    23  )
    24  
    25  type event struct {
    26  	key              string
    27  	value            []byte
    28  	prevValue        []byte
    29  	rev              int64
    30  	isDeleted        bool
    31  	isCreated        bool
    32  	isProgressNotify bool
    33  	// isInitialEventsEndBookmark helps us keep track
    34  	// of whether we have sent an annotated bookmark event.
    35  	//
    36  	// when this variable is set to true,
    37  	// a special annotation will be added
    38  	// to the bookmark event.
    39  	//
    40  	// note that we decided to extend the event
    41  	// struct field to eliminate contention
    42  	// between startWatching and processEvent
    43  	isInitialEventsEndBookmark bool
    44  }
    45  
    46  // parseKV converts a KeyValue retrieved from an initial sync() listing to a synthetic isCreated event.
    47  func parseKV(kv *mvccpb.KeyValue) *event {
    48  	return &event{
    49  		key:       string(kv.Key),
    50  		value:     kv.Value,
    51  		prevValue: nil,
    52  		rev:       kv.ModRevision,
    53  		isDeleted: false,
    54  		isCreated: true,
    55  	}
    56  }
    57  
    58  func parseEvent(e *clientv3.Event) (*event, error) {
    59  	if !e.IsCreate() && e.PrevKv == nil {
    60  		// If the previous value is nil, error. One example of how this is possible is if the previous value has been compacted already.
    61  		return nil, fmt.Errorf("etcd event received with PrevKv=nil (key=%q, modRevision=%d, type=%s)", string(e.Kv.Key), e.Kv.ModRevision, e.Type.String())
    62  
    63  	}
    64  	ret := &event{
    65  		key:       string(e.Kv.Key),
    66  		value:     e.Kv.Value,
    67  		rev:       e.Kv.ModRevision,
    68  		isDeleted: e.Type == clientv3.EventTypeDelete,
    69  		isCreated: e.IsCreate(),
    70  	}
    71  	if e.PrevKv != nil {
    72  		ret.prevValue = e.PrevKv.Value
    73  	}
    74  	return ret, nil
    75  }
    76  
    77  func progressNotifyEvent(rev int64) *event {
    78  	return &event{
    79  		rev:              rev,
    80  		isProgressNotify: true,
    81  	}
    82  }