├── README.md
└── lock.go


/README.md:
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1 | # go_redis_lock
2 | 


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/lock.go:
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 1 | package main
 2 | 
 3 | import (
 4 | 	"fmt"
 5 | 	"log"
 6 | 	"time"
 7 | 
 8 | 	"github.com/garyburd/redigo/redis"
 9 | )
10 | 
11 | type Lock struct {
12 | 	resource string
13 | 	token    string
14 | 	conn     redis.Conn
15 | 	timeout  int
16 | }
17 | 
18 | func (lock *Lock) tryLock() (ok bool, err error) {
19 | 	_, err = redis.String(lock.conn.Do("SET", lock.key(), lock.token, "EX", int(lock.timeout), "NX"))
20 | 	if err == redis.ErrNil {
21 | 		// The lock was not successful, it already exists.
22 | 		return false, nil
23 | 	}
24 | 	if err != nil {
25 | 		return false, err
26 | 	}
27 | 	return true, nil
28 | }
29 | 
30 | func (lock *Lock) Unlock() (err error) {
31 | 	_, err = lock.conn.Do("del", lock.key())
32 | 	return
33 | }
34 | 
35 | func (lock *Lock) key() string {
36 | 	return fmt.Sprintf("redislock:%s", lock.resource)
37 | }
38 | 
39 | func (lock *Lock) AddTimeout(ex_time int64) (ok bool, err error) {
40 | 	ttl_time, err := redis.Int64(lock.conn.Do("TTL", lock.key()))
41 | 	if err != nil {
42 | 		log.Fatal("redis get failed:", err)
43 | 	}
44 | 	if ttl_time > 0 {
45 | 		_, err := redis.String(lock.conn.Do("SET", lock.key(), lock.token, "EX", int(ttl_time+ex_time)))
46 | 		if err == redis.ErrNil {
47 | 			return false, nil
48 | 		}
49 | 		if err != nil {
50 | 			return false, err
51 | 		}
52 | 	}
53 | 	return false, nil
54 | }
55 | 
56 | func TryLock(conn redis.Conn, resource string, token string, DefaulTimeout int) (lock *Lock, ok bool, err error) {
57 | 	return TryLockWithTimeout(conn, resource, token, DefaulTimeout)
58 | }
59 | 
60 | func TryLockWithTimeout(conn redis.Conn, resource string, token string, timeout int) (lock *Lock, ok bool, err error) {
61 | 	lock = &Lock{resource, token, conn, timeout}
62 | 
63 | 	ok, err = lock.tryLock()
64 | 
65 | 	if !ok || err != nil {
66 | 		lock = nil
67 | 	}
68 | 
69 | 	return
70 | }
71 | 
72 | func main() {
73 | 	fmt.Println("start")
74 | 	DefaultTimeout := 10
75 | 	conn, err := redis.Dial("tcp", "localhost:6379")
76 | 
77 | 	lock, ok, err := TryLock(conn, "xiaoru.cc", "token", int(DefaultTimeout))
78 | 	if err != nil {
79 | 		log.Fatal("Error while attempting lock")
80 | 	}
81 | 	if !ok {
82 | 		log.Fatal("bug")
83 | 	}
84 | 	lock.AddTimeout(100)
85 | 
86 | 	time.Sleep(time.Duration(DefaultTimeout) * time.Second)
87 | 	fmt.Println("end")
88 | 	defer lock.Unlock()
89 | }
90 | 


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