etcd/storage/kv.go

100 lines
3.6 KiB
Go

// Copyright 2015 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package storage
import (
"github.com/coreos/etcd/storage/backend"
"github.com/coreos/etcd/storage/storagepb"
)
// CancelFunc tells an operation to abandon its work. A CancelFunc does not
// wait for the work to stop.
type CancelFunc func()
type Snapshot backend.Snapshot
type KV interface {
// Rev returns the current revision of the KV.
Rev() int64
// Range gets the keys in the range at rangeRev.
// If rangeRev <=0, range gets the keys at currentRev.
// If `end` is nil, the request returns the key.
// If `end` is not nil, it gets the keys in range [key, range_end).
// Limit limits the number of keys returned.
// If the required rev is compacted, ErrCompacted will be returned.
Range(key, end []byte, limit, rangeRev int64) (kvs []storagepb.KeyValue, rev int64, err error)
// Put puts the given key,value into the store.
// A put also increases the rev of the store, and generates one event in the event history.
Put(key, value []byte) (rev int64)
// DeleteRange deletes the given range from the store.
// A deleteRange increases the rev of the store if any key in the range exists.
// The number of key deleted will be returned.
// It also generates one event for each key delete in the event history.
// if the `end` is nil, deleteRange deletes the key.
// if the `end` is not nil, deleteRange deletes the keys in range [key, range_end).
DeleteRange(key, end []byte) (n, rev int64)
// TxnBegin begins a txn. Only Txn prefixed operation can be executed, others will be blocked
// until txn ends. Only one on-going txn is allowed.
// TxnBegin returns an int64 txn ID.
// All txn prefixed operations with same txn ID will be done with the same rev.
TxnBegin() int64
// TxnEnd ends the on-going txn with txn ID. If the on-going txn ID is not matched, error is returned.
TxnEnd(txnID int64) error
TxnRange(txnID int64, key, end []byte, limit, rangeRev int64) (kvs []storagepb.KeyValue, rev int64, err error)
TxnPut(txnID int64, key, value []byte) (rev int64, err error)
TxnDeleteRange(txnID int64, key, end []byte) (n, rev int64, err error)
Compact(rev int64) error
// Get the hash of KV state.
// This method is designed for consistency checking purpose.
Hash() (uint32, error)
// Snapshot snapshots the full KV store.
Snapshot() Snapshot
// Commit commits txns into the underlying backend.
Commit()
Restore() error
Close() error
}
// WatchableKV is a KV that can be watched.
type WatchableKV interface {
KV
Watchable
}
// Watchable is the interface that wraps the NewWatcher function.
type Watchable interface {
// NewWatcher returns a Watcher that can be used to
// watch events happened or happending on the KV.
NewWatcher() Watcher
}
// ConsistentWatchableKV is a WatchableKV that understands the consistency
// algorithm and consistent index.
// If the consistent index of executing entry is not larger than the
// consistent index of ConsistentWatchableKV, all operations in
// this entry are skipped and return empty response.
type ConsistentWatchableKV interface {
WatchableKV
}