Redis distributed lock + Lua atomic operation

package com.example.demo.redis;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.StringUtils;
import redis.clients.jedis.JedisCluster;
import redis.clients.jedis.exceptions.JedisNoScriptException;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class RedisLockUtil {
    

    // Distributed lock related fields 
    private static final String LOCK_SUCCESS = "OK";
    private static final String SET_IF_NOT_EXIST = "NX";
    private static final String SET_WITH_EXPIRE_TIME = "PX";
    private static final Long RELEASE_SUCCESS = 1L;
    private static final Long UNLOCK_SUCCESS_CODE = 1L;
    private volatile String unlockSha1 = "";

    private static final Logger logger = LoggerFactory.getLogger(RedisLockUtil.class);

    /** *  adopt lua Script release lock , To achieve the atomic operation of releasing the lock  *  Judge whether the lock value is held by the current thread , Unlock if yes , If not, unlocking fails  */
    String UNLOCK_LUA = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";

    @Autowired
    private JedisCluster jedisCluster;

    /** *  according to loopTryTime Loop retry  * @param lockKey  lock key * @param lockVal  Lock value , Used for unlocking verification  * @param expiryTime  Lock expiration time  * @param loopTryTime  When get fails , The length of time to cycle and retry to acquire the lock  * @return  Whether to obtain the lock  */
    public boolean tryLock(String lockKey, String lockVal, long expiryTime, long loopTryTime){
    
        Long endTime = System.currentTimeMillis() + loopTryTime;
        while (System.currentTimeMillis() < endTime){
    
            if (tryGetDistributedLock(lockKey, lockVal, expiryTime)){
    
                return true;
            }
        }
        return false;
    }

    /** *  Try to get distributed lock  * @param lockKey  lock  * @param requestId  The request id  * @param expireTime  Beyond the time  * @return  Success or failure  */
    public Boolean tryGetDistributedLock(String lockKey, String requestId, long expireTime) {
    
        String result = jedisCluster.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);
        if (LOCK_SUCCESS.equals(result)) {
    
            return Boolean.TRUE;
        }
        return Boolean.FALSE;
    }

    /** *  Release distributed lock  * @param lockKey  lock  * @param requestId  The request id  * @return  Whether to release successfully  */
    public Boolean tryUnLockEval(String lockKey, String requestId) {
    
        Object result = jedisCluster.eval(UNLOCK_LUA, Collections.singletonList(lockKey), Collections.singletonList(requestId));
        if (RELEASE_SUCCESS.equals(result)) {
    
            return Boolean.TRUE;
        }
        return Boolean.FALSE;
    }

    /** *  Release distributed lock , The most likely reason for release failure is that the business execution time is longer than lockKey Expiration time , The expiration time should be adjusted according to the business scenario  * @param lockKey  lock key * @param lockVal  Lock value  * @return  Whether to release successfully  */
    public boolean tryUnLockEvalsha(String lockKey, String lockVal){
    
        List<String> keys = new ArrayList<>();
        keys.add(lockKey);
        List<String> argv = new ArrayList<>();
        argv.add(lockVal);
        try {
    
            Object result = jedisCluster.evalsha(unlockSha1, keys, argv);
            return UNLOCK_SUCCESS_CODE.equals(result);
        } catch (JedisNoScriptException e){
    
            // When there is no script cache , Resend cache 
            logger.info("try to store script......");
            storeScript(lockKey);
            Object result = jedisCluster.evalsha(unlockSha1, keys, argv);
            return UNLOCK_SUCCESS_CODE.equals(result);
        } catch (Exception e){
    
            logger.info(e.getMessage());
            return false;
        }
    }
    /** *  Due to the use redis colony , Therefore, each node needs to cache a copy of script data  * @param slotKey  Used to locate the corresponding slot Of slotKey */
    public void storeScript(String slotKey){
    
        if (StringUtils.isEmpty(unlockSha1) || !jedisCluster.scriptExists(unlockSha1, slotKey)){
    
            //redis Support script caching , Return hash code , Later, it can be used to call scripts 
            unlockSha1 = jedisCluster.scriptLoad(UNLOCK_LUA, slotKey);
        }
    }

}