const redisClient = require('redis').createClient(6379, '127.0.0.1');
const crypto = require('crypto')
const lockScript = 'return redis.call("set", KEYS[1], ARGV[1], "NX", "PX", ARGV[2])'
const unlockScript = 'if redis.call("get", KEYS[1]) == ARGV[1] then return redis.call("del", KEYS[1]) else return 0 end'
redisClient.set("num","0")
for(let i=0;i<1000;i++) add()
for(let i=0;i<1000;i++) add()
for(let i=0;i<1000;i++) add()
async function add() {
let resourse = "lock:num"
let uniqueStr = crypto.randomBytes(10).toString('hex')
await attemplock(resourse, uniqueStr)
let nowCityNum = Number(await get('num'))
num++
await set('num', String(num))
await unlock(resourse, uniqueStr)
}
async function loop(resourse, uniqueStr, ttl) {
return new Promise((resolve, reject) => {
setTimeout(async () => {
let result = await lock(resourse, uniqueStr, ttl)
resolve(!!result)
}, 10)
})
}
async function attemplock(resourse, uniqueStr, ttl) {
let result = await loop(resourse, uniqueStr, ttl)
if (result) {
return true
} else {
return attemplock(resourse, uniqueStr, ttl)
}
}
async function lock(resourse, uniqueStr, ttl) {
ttl = ttl ? ttl : "30000"
return new Promise((resolve, reject) => {
redisClient.eval(lockScript, 1, resourse, uniqueStr, ttl, (err, reply) => {
if (err) {
console.error(err)
reject(err)
}
resolve(reply)
})
})
}
async function unlock(resourse, uniqueStr) {
return new Promise((resolve, reject) => {
redisClient.eval(unlockScript, 1, resourse, uniqueStr, (err, reply) => {
if (err) {
console.error(err)
reject(err)
}
resolve(reply)
})
})
}
async function get(key) {
return new Promise((resolve, reject) => {
redisClient.get(key, (err, reply) => {
if (err) {
console.error(err);
reject(err)
}
resolve(reply)
})
})
}
async function set(key, value) {
return new Promise((resolve, reject) => {
redisClient.set(key, value, (err, reply) => {
if (err) {
console.error(err)
reject(err)
}
resolve(reply)
})
})
}
async function setnx(key, value) {
return new Promise((resolve, reject) => {
redisClient.setnx(key, value, (err, reply) => {
if (err) {
console.error(err)
reject(err)
}
resolve(reply)
})
})
}