mirror of
https://github.com/featurebasedb/featurebase.git
synced 2026-10-09 04:17:51 +00:00
7a1e4cd2d7
Added a leasedKV struct in charge of maintain a lease for a specific key. Signed-off-by: Antonio Navarro Perez <antnavper@gmail.com>
119 lines
2.8 KiB
Go
119 lines
2.8 KiB
Go
// Copyright 2017 Pilosa Corp.
|
|
//
|
|
// 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 etcd
|
|
|
|
import (
|
|
"context"
|
|
"sync"
|
|
|
|
"github.com/pilosa/pilosa/v2/disco"
|
|
"github.com/pkg/errors"
|
|
"go.etcd.io/etcd/clientv3"
|
|
"go.etcd.io/etcd/clientv3/clientv3util"
|
|
)
|
|
|
|
type leasedKV struct {
|
|
cli *clientv3.Client
|
|
cancel context.CancelFunc
|
|
|
|
mu sync.Mutex
|
|
|
|
key, value string
|
|
ttlSeconds int64
|
|
}
|
|
|
|
func newLeasedKV(cli *clientv3.Client, key string, ttlSeconds int64) *leasedKV {
|
|
return &leasedKV{
|
|
cli: cli,
|
|
key: key,
|
|
ttlSeconds: ttlSeconds,
|
|
}
|
|
}
|
|
|
|
func (l *leasedKV) Start(ctx context.Context, initValue string) error {
|
|
l.mu.Lock()
|
|
defer l.mu.Unlock()
|
|
|
|
ctx, cancel := context.WithCancel(ctx)
|
|
l.cancel = cancel
|
|
|
|
return l.create(ctx, initValue)
|
|
}
|
|
|
|
func (l *leasedKV) create(ctx context.Context, initValue string) error {
|
|
leaseResp, err := l.cli.Grant(ctx, l.ttlSeconds)
|
|
if err != nil {
|
|
return errors.Wrap(err, "creating a lease")
|
|
}
|
|
|
|
if _, err := l.cli.Txn(ctx).
|
|
Then(clientv3.OpPut(l.key, initValue, clientv3.WithLease(leaseResp.ID))).
|
|
Commit(); err != nil {
|
|
return errors.Wrapf(err, "creating key %s with value [%s]", l.key, initValue)
|
|
}
|
|
|
|
if _, err := l.cli.KeepAlive(ctx, leaseResp.ID); err != nil {
|
|
return errors.Wrapf(err, "keeping alive the lease for the key %s with value %s", l.key, l.value)
|
|
}
|
|
|
|
l.value = initValue
|
|
|
|
return nil
|
|
}
|
|
|
|
func (l *leasedKV) Stop() {
|
|
l.mu.Lock()
|
|
defer l.mu.Unlock()
|
|
|
|
if l.cancel != nil {
|
|
l.cancel()
|
|
}
|
|
}
|
|
|
|
func (l *leasedKV) Set(ctx context.Context, value string) error {
|
|
l.mu.Lock()
|
|
defer l.mu.Unlock()
|
|
|
|
if _, err := l.cli.Txn(ctx).
|
|
Then(clientv3.OpPut(l.key, value, clientv3.WithIgnoreLease())).
|
|
Commit(); err != nil {
|
|
return errors.Wrapf(err, "creating key %s with value [%s]", l.key, l.value)
|
|
}
|
|
|
|
l.value = value
|
|
|
|
return nil
|
|
}
|
|
|
|
func (l *leasedKV) Get(ctx context.Context) (string, error) {
|
|
l.mu.Lock()
|
|
defer l.mu.Unlock()
|
|
|
|
getResp, err := l.cli.Txn(ctx).
|
|
If(clientv3util.KeyExists(l.key)).
|
|
Then(clientv3.OpGet(l.key, clientv3.WithIgnoreLease())).
|
|
Commit()
|
|
if err != nil {
|
|
return "", errors.Wrapf(err, "getting key %s", l.key)
|
|
}
|
|
|
|
if !getResp.Succeeded || len(getResp.Responses) == 0 {
|
|
return "", disco.ErrNoResults
|
|
}
|
|
|
|
l.value = string(getResp.Responses[0].GetResponseRange().Kvs[0].Value)
|
|
|
|
return l.value, nil
|
|
}
|