1.redis-lua 相关命令
#执行 Lua 脚本 EVAL script numkeys key [key ...] arg [arg ...] EVALSHA sha1 numkeys key [key ...] arg [arg ...] #查看指定的脚本是否已经被保存在缓存当中。 SCRIPT EXISTS script [script ...] #从脚本缓存中移除所有脚本。 SCRIPT FLUSH #杀死当前正在运行的 Lua 脚本 SCRIPT KILL #添加一个Lua脚本到内存 SCRIPT LOAD script
2.redis执行Lua方式
#1.redis中执行 会把脚本加载到内存中 EVAL script numkeys key [key ...] arg [arg ...] EVALSHA sha1 numkeys key [key ...] arg [arg ...] #2.本地执行 不会把脚本加载到内存中 redis-cli --eval test.lua aaa,bbb
3.执行Lua原理
根据Lua脚本计算出一个sha1值 如果sha1存在redis内存中 就用内存中的 # redis 查看是否加载过某个lua脚本 SCRIPT EXISTS sha1值
4.证明
计算 lua脚本SHA1值
package plantomjs;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* @author
* @since 2020—01-09
*/
public class PlanTomJs {
public static void main(String[] args) throws NoSuchAlgorithmException {
//lua 脚本
String lua =
"local getnum = function( count )\n"
+ "\tif count == false then\n"
+ "\t\treturn 0 ;\n"
+ "\telse\t\n"
+ "\t\treturn count ; \n"
+ "\tend\n"
+ "\treturn 0 ;\n"
+ "end\t\n"
+ "local plan = KEYS[1] ;\n"
+ "local result = redis.call('get', KEYS[2] );\n"
+ "local keywordPlan = KEYS[3] ;\n"
+ "local keywordResult = redis.call('get', KEYS[4] ) ;\n"
+ "\n"
+ "if tonumber(getnum(plan)) > tonumber(getnum(result)) and tonumber(getnum(keywordPlan)) > tonumber(getnum(keywordResult)) then\n"
+ " \tredis.call('incrby', KEYS[2] , 1 );\n"
+ " \tredis.call('incrby', KEYS[4] , 1 );\n"
+ " \tredis.call('expire', KEYS[2] , 60*60*24 );\n"
+ " \tredis.call('expire', KEYS[4] , 60*60*24 );\n"
+ " \treturn '1';\n"
+ " else\n"
+ " \treturn '0';\n"
+ " end\t\t\n"
+ "\n";
System.out.println(getSha1(lua.getBytes()));
}
public static String getSha1(byte[] input) throws NoSuchAlgorithmException {
MessageDigest mDigest = MessageDigest.getInstance("SHA1");
byte[] result = mDigest.digest(input);
StringBuffer sb = new StringBuffer();
for (int i = 0; i < result.length; i++) {
sb.append(Integer.toString((result[i] & 0xff) + 0x100, 16).substring(1));
}
return sb.toString();
}
SHA1值为 8f8b5c2314b53cd128e2ead7b9e5d42f5f1eabe8
说明 存在redis内存中
5.查看redis -lua相关配置
#Lua 引擎所使用的内存大小(以字节为单位) used_memory_lua:46080 #同上 used_memory_lua_human:45.00K #Lua脚本占用内存大小 used_memory_scripts:53784 used_memory_scripts_human:52.52K #内存中已加载的Lua脚本数量 number_of_cached_scripts:95
6.项目中使用redis-lua脚本(spring-data-redis)
private boolean ipLuaCheckCount(String ip, App app) {
String lua = "\n"
+ "local result = redis.call('hget', KEYS[1] , ARGV[1])\n"
+ "if result == false then \n"
+ "\tresult = 0 ;\n"
+ "end\n"
+ "local num = KEYS[2] \n"
+ "if tonumber(result) < tonumber(num) then\n"
+ "\tredis.call('hincrby', KEYS[1] ,ARGV[1] , 1 )\n"
+ "\tredis.call('expire', KEYS[1] , 60*60*24 )\n"
+ "\treturn '1' ;\n"
+ "else \n"
+ "\treturn '0' ; \n"
+ "end\n"
+ "\n";
DefaultRedisScript<String> rs = new DefaultRedisScript<>();
//设置脚本
rs.setScriptText(lua);
//定义返回类型。注意如果没有这个定义,spring不会返回结果
rs.setResultType(String.class);
RedisSerializer valueSerializer = jsonRedisTemplate.getValueSerializer();
RedisSerializer stringSerializer = jsonRedisTemplate.getStringSerializer();
List<String> keyList = new ArrayList<>();
keyList.add(RedisKeys.ipMonitorResult(app.getId()));
keyList.add(Objects.nonNull(app.getIpMonitorCount()) ? String.valueOf(app.getIpMonitorCount()) : String.valueOf(3));
List<String> valsList = new ArrayList<>();
valsList.add(ip);
String restult = redisTemplate.execute(rs, valueSerializer, stringSerializer, keyList, valsList.toArray());
if ("0".equals(restult)) {
throw new ConnectException(ConnectExceptionEnum.IP_TASK_BE_ALREADY_FULL);
}
return true;
}