메리

* Redis
- 데이터를 디스크에 쓰는 구조가 아니라 메모리에서 데이터를 처리 => 속도 빠름
- 서버 장애등으로 redis 종료 될 시 데이터 유실이 발생할 수 있음
- 한 번에 하나의 명령만 처리할 수 있음
- Redis Cluster를 사용하면 여러개의 redis를 두어 분산처리를 할 수 있음

* String, Lists, Sets, Sorted Sets, Hashes 자료 구조를 지원함
- String : 가장 일반적인 key & value 
- Sets : key & 여러 값이 들어간 value 
- Sorted Sets : 중복된 데이터를 담지 않는 Set 구조
- Lists : Array 형식의 데이터 구조

* Redis Cluster
여러 노드간 데이터를 자동으로 분할하는 기능 .
각기 다른 서버를 하나로 묶어 
데이터를 여러대의 장비에서 처리한다.
서버일부분이 장애가 일어나도 다른 서버의 보완을 통해 서비스를 계속 이어 나갈수 있다.

레디스  GUI 툴 

https://redis.com/redis-enterprise/redis-insight/

Springboot 어플리케이션에서 redis 사용하기

1. 의존성 추가 

implementation 'org.springframework.boot:spring-boot-starter-data-redis'

2. application.properties 에 redis 서버정보 추가

spring.data.redis.host=localhost
spring.data.redis.port=6379

3. RedisConfig.java

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;

@Configuration
public class RedisConfig {

   @Value("${spring.data.redis.host}")
   private String host;

   @Value("${spring.data.redis.port}")
   private int port;

   @Value("${spring.data.redis.password}")
   private int password;

   @Bean
   public RedisConnectionFactory redisConnectionFactory() {
	RedisStandaloneConfiguration redisConfiguration = new RedisStandaloneConfiguration();
	redisConfiguration.setHostName(host);
	redisConfiguration.setPort(port);
	redisConfiguration.setPassword(password);
	LettuceConnectionFactory lettuceConnectionFactory = new LettuceConnectionFactory(redisConfiguration);

       return new LettuceConnectionFactory;
   }
   
   @Primary
   @Bean
   public RedisTemplate<String, String> redisTemplate() {
       RedisTemplate<String, String> redisTemplate = new RedisTemplate<>();
       redisTemplate.setConnectionFactory(redisConnectionFactory());
       redisTemplate.setKeySerializer(new StringRedisSerializer());
       redisTemplate.setValueSerializer(new StringRedisSerializer());
       return redisTemplate;
   }

}

RedisTemplate : 트랜잭션을 지원한다. 트랜잭션으로 묶게 되면 트랜잭션 내부에서 하나의 로직이 실패하여 오류가 나는 경우 수행한 작업을 모두 취소시킨다.

4. RedisService.java

import lombok.RequiredArgsConstructor;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.TimeUnit;


@Service
@RequiredArgsConstructor
public class RedisService {
   private final RedisTemplate redisTemplate;


   public String getValues(String key){
       //opsForValue : Strings를 쉽게 Serialize / Deserialize 해주는 Interface
       ValueOperations<String, String> values = redisTemplate.opsForValue();
       return values.get(key);
   }



   public void setValues(String key, String value){
       ValueOperations<String, String> values = redisTemplate.opsForValue();
       values.set(key,value);
   }

   public void setSets(String key,String... values){
       redisTemplate.opsForSet().add(key,values);
   }

   public Set getSets(String key){
       return redisTemplate.opsForSet().members(key);
   }



}

5. RedisController.java

api를 만들어서 데이터를 넣고 요청해보었다.

import com.dominos.pilot_3.service.RedisService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.sql.Timestamp;
import java.util.Set;

@Controller
public class RedisController_ {
//레디스 테스트

    @Autowired
    RedisService redisService;

    @RequestMapping(value = "/redis/test/setString")
    @ResponseBody
    public void setValue(String testkey, String testvalue){
        Timestamp currentTimestamp = new Timestamp(System.currentTimeMillis());
        redisService.setValues(testkey,testvalue);
    }

    @RequestMapping(value = "/redis/test/getString")
    @ResponseBody
    public String getValue(String testkey){
        return redisService.getValues(testkey);
    }


    @RequestMapping(value = "/redis/test/setSets")
    @ResponseBody
    public void setSets(String testkey,String... testvalues){
        redisService.setSets(testkey,testvalues);
    }

    @RequestMapping(value = "/redis/test/getSets")
    @ResponseBody
    public Set getSets(String key){
        return redisService.getSets(key);
    }

}

123123123는 Key와 123123123이라는 Value 쌍을 넣어봤다.

settest라는 Key와 ["settestvalue1","settestvalue2"] 라는 Value 쌍을 넣어봤다.

Redis Cluster를 사용하는 경우의 설정

1. application.yml

spring:
 data:
  redis:
    cluster:
      nodes:
        - xx.xx.xx.xxx:6379
        - xx.xx.xx.xxx:6380
    password: xxxxxxxxxx

2. RedisClusterConfigurationProperties.java

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import java.util.List;

@Component
@ConfigurationProperties(prefix = "spring.data.redis.cluster")
public class RedisClusterConfigurationProperties {
   List<String> nodes;

   public List<String> getNodes() {
       return nodes;
   }

   public void setNodes(List<String> nodes) {
       this.nodes = nodes;
   }

}

3. RedisConfig.java

import com.dominos.pilot_3.component.RedisClusterConfigurationProperties;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.connection.RedisClusterConfiguration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.repository.configuration.EnableRedisRepositories;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
@EnableRedisRepositories
@RequiredArgsConstructor

public class RedisConfig {

   @Autowired
   RedisClusterConfigurationProperties clusterProperties;

   @Bean
   public RedisConnectionFactory redisConnectionFactory() {
       RedisClusterConfiguration redisConfig = new RedisClusterConfiguration ();
       clusterProperties.getNodes().forEach(s ->{
           String[] url = s.split(":");
           redisConfig.clusterNode(url[0],Integer.parseInt(url[1]));
       });
       redisConfig.setPassword("xxxxxxxx");
       return new LettuceConnectionFactory(redisConfig);
   }

   @Primary
   @Bean
   public RedisTemplate<String, Object> redisTemplate() {
       RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
       redisTemplate.setConnectionFactory(redisConnectionFactory());
       redisTemplate.setKeySerializer(new StringRedisSerializer());
       redisTemplate.setValueSerializer(new Jackson2JsonRedisSerializer<>(Object.class));
       return redisTemplate;
   }

}

이하 데이터를 넣고 빼는 service와 controller는 동일함.