// Copyright (c) 2015-2021 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. package cmd import (	"context"	"errors"	"fmt" 	"github.com/minio/minio/internal/logger"	etcd "go.etcd.io/etcd/client/v3") var errEtcdUnreachable = errors.New("etcd is unreachable, please check your endpoints") func etcdErrToErr(err error, etcdEndpoints []string) error {	if err == nil {		return nil	}	switch err {	case context.DeadlineExceeded:		return fmt.Errorf("%w %s", errEtcdUnreachable, etcdEndpoints)	default:		return fmt.Errorf("unexpected error %w from etcd, please check your endpoints %s", err, etcdEndpoints)	}} func saveKeyEtcdWithTTL(ctx context.Context, client *etcd.Client, key string, data []byte, ttl int64) error {	timeoutCtx, cancel := context.WithTimeout(ctx, defaultContextTimeout)	defer cancel()	lease, err := client.Grant(timeoutCtx, ttl)	if err != nil {		return etcdErrToErr(err, client.Endpoints())	}	_, err = client.Put(timeoutCtx, key, string(data), etcd.WithLease(lease.ID))	logger.LogIf(ctx, err)	return etcdErrToErr(err, client.Endpoints())} func saveKeyEtcd(ctx context.Context, client *etcd.Client, key string, data []byte, opts ...options) error {	timeoutCtx, cancel := context.WithTimeout(ctx, defaultContextTimeout)	defer cancel()	if len(opts) > 0 {		return saveKeyEtcdWithTTL(ctx, client, key, data, opts[0].ttl)	}	_, err := client.Put(timeoutCtx, key, string(data))	logger.LogIf(ctx, err)	return etcdErrToErr(err, client.Endpoints())} func deleteKeyEtcd(ctx context.Context, client *etcd.Client, key string) error {	timeoutCtx, cancel := context.WithTimeout(ctx, defaultContextTimeout)	defer cancel() 	_, err := client.Delete(timeoutCtx, key)	logger.LogIf(ctx, err)	return etcdErrToErr(err, client.Endpoints())} func readKeyEtcd(ctx context.Context, client *etcd.Client, key string) ([]byte, error) {	timeoutCtx, cancel := context.WithTimeout(ctx, defaultContextTimeout)	defer cancel()	resp, err := client.Get(timeoutCtx, key)	if err != nil {		logger.LogIf(ctx, err)		return nil, etcdErrToErr(err, client.Endpoints())	}	if resp.Count == 0 {		return nil, errConfigNotFound	}	for _, ev := range resp.Kvs {		if string(ev.Key) == key {			return ev.Value, nil		}	}	return nil, errConfigNotFound}