gopkg/middleware/etcd/lease.go

// Package etcd ...
//
// Description : 租约相关操作
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 2021-11-23 6:03 下午
package etcd

import (
	"context"

	"github.com/pkg/errors"
	"go.etcd.io/etcd/clientv3"
)

// LeaseOnce 申请一个一次性租约
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 6:06 下午 2021/11/23
func LeaseOnce(ctx context.Context, key string, val string, ttl int64) error {
	if ttl <= 0 {
		return errors.New("lease time must be more than 0")
	}
	if nil == ctx {
		ctx = context.TODO()
	}
	var (
		resp *clientv3.LeaseGrantResponse
		err  error
	)
	// 创建一个5秒的租约
	if resp, err = Client.Grant(ctx, ttl); err != nil {
		return errors.New("lease grant error : " + err.Error())
	}

	// ttl 秒钟之后,  这个key就会被移除
	if _, err = Client.Put(context.TODO(), key, val, clientv3.WithLease(resp.ID)); err != nil {
		return errors.New("lease key put fail : " + err.Error())
	}
	return nil
}

// LeaseKeepAliveForever 无限续租一个key
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 7:40 下午 2021/11/23
func LeaseKeepAliveForever(ctx context.Context, key string, val string, ttl int64, keepAliveHandler LeaseKeepALiveHandler) error {
	if ttl <= 0 {
		return errors.New("lease time must be more than 0")
	}
	if nil == ctx {
		ctx = context.TODO()
	}
	var (
		resp     *clientv3.LeaseGrantResponse
		respChan <-chan *clientv3.LeaseKeepAliveResponse
		err      error
	)
	// 创建一个5秒的租约
	if resp, err = Client.Grant(ctx, ttl); err != nil {
		return errors.New("lease grant error : " + err.Error())
	}

	// ttl 秒钟之后,  这个key就会被移除
	if _, err = Client.Put(context.TODO(), key, val, clientv3.WithLease(resp.ID)); err != nil {
		return errors.New("lease key put fail : " + err.Error())
	}
	// the key will be kept forever
	if respChan, err = Client.KeepAlive(ctx, resp.ID); nil != err {
		return errors.New("lease keep alive fail : " + err.Error())
	}
	// 监听 chan
	for ka := range respChan {
		if nil != keepAliveHandler {
			keepAliveHandler(key, ka)
		}
	}
	return nil
}