因为最近在使用WebFlux开发，在集成Redis的时候使用了Spring Data Redis 2.0提供的Reactive接口。 发现了几个问题，顺手看了下源码，然后提了几个PR。
DATAREDIS-779 ReactiveValueOperations.set[ifPresent|ifAbsent](…) does not return a value if value was not set
DATAREDIS-782 Add support for SET key value NX EX max-lock-time
DATAREDIS-783 Fix typo in LettuceReactiveRedisConnection
DATAREDIS-784 Add support for reactive [INCR | INCRBY | INCRBYFLOAT | DECR | DECRBY]
0x01 Auto-Configuration
这个框架是Spring对Redis的胶水框架，集成了Jedis和Lettuce这两个java的redis客户端。整个项目的命令核心接口都在org.springframework.data.redis.connection目录下，分为响应式接口和响应式接口。
// org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration
@Configuration
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
@Import({ LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class })
public class RedisAutoConfiguration {
...
}
@Configuration
@ConditionalOnClass(RedisClient.class)
class LettuceConnectionConfiguration extends RedisConnectionConfiguration {
@Bean
@ConditionalOnMissingBean(RedisConnectionFactory.class)
public LettuceConnectionFactory redisConnectionFactory(
ClientResources clientResources) throws UnknownHostException {
LettuceClientConfiguration clientConfig = getLettuceClientConfiguration(
clientResources, this.properties.getLettuce().getPool());
return createLettuceConnectionFactory(clientConfig);
}
private LettuceConnectionFactory createLettuceConnectionFactory(
LettuceClientConfiguration clientConfiguration) {
if (getSentinelConfig() != null) {
return new LettuceConnectionFactory(getSentinelConfig(), clientConfiguration);
}
if (getClusterConfiguration() != null) {
return new LettuceConnectionFactory(getClusterConfiguration(),
clientConfiguration);
}
return new LettuceConnectionFactory(getStandaloneConfig(), clientConfiguration);
}
protected final RedisClusterConfiguration getClusterConfiguration() {
if (this.clusterConfiguration != null) {
return this.clusterConfiguration;
}
if (this.properties.getCluster() == null) {
return null;
}
RedisProperties.Cluster clusterProperties = this.properties.getCluster();
RedisClusterConfiguration config = new RedisClusterConfiguration(
clusterProperties.getNodes());
if (clusterProperties.getMaxRedirects() != null) {
config.setMaxRedirects(clusterProperties.getMaxRedirects());
}
if (this.properties.getPassword() != null) {
config.setPassword(RedisPassword.of(this.properties.getPassword()));
}
return config;
}
...
}
RedisAutoConfiguration判断是否有Lettuce的依赖，然后解析spring.redis的ConfigurationProperties创建好配置Bean或者通过ObjectProvider来获取各种配置bean。
0x02 阻塞式API结构
阻塞式连接接口:
public interface RedisCommands extends RedisKeyCommands, RedisStringCommands, RedisListCommands, RedisSetCommands,
RedisZSetCommands, RedisHashCommands, RedisTxCommands, RedisPubSubCommands, RedisConnectionCommands,
RedisServerCommands, RedisScriptingCommands, RedisGeoCommands, RedisHyperLogLogCommands
Object execute(String command, byte[]... args);
}
public interface RedisConnection extends RedisCommands {
default RedisGeoCommands geoCommands() {
return this;
}
default RedisHashCommands hashCommands() {
return this;
}
default RedisHyperLogLogCommands hyperLogLogCommands() {
return this;
}
default RedisKeyCommands keyCommands() {
return this;
}
default RedisListCommands listCommands() {
return this;
}
default RedisSetCommands setCommands() {
return this;
}
...
}
Spring Data Redis基于命令模式，这些Command的接口实现大同小异，无非是通过调用jedis或lettuce连接中的execute方法来调用这些命令，实现在standalone和cluster不同环境中的调用。但是对阻塞式接口的事务和pipeline的支持过于粗糙，需要在每个方法里面去做特殊判断，Orz。
0x03 响应式API结构
Reactive命令接口:
public interface ReactiveRedisConnection extends Closeable {
@Override
void close();
/**
* Get {@link ReactiveKeyCommands}.
*
* @return never {@literal null}.
*/
ReactiveKeyCommands keyCommands();
/**
* Get {@link ReactiveStringCommands}.
*
* @return never {@literal null}.
*/
ReactiveStringCommands stringCommands();
/**
* Get {@link ReactiveNumberCommands}
*
* @return never {@literal null}.
*/
ReactiveNumberCommands numberCommands();
/**
* Get {@link ReactiveListCommands}.
*
* @return never {@literal null}.
*/
ReactiveListCommands listCommands();
/**
* Get {@link ReactiveSetCommands}.
*
* @return never {@literal null}.
*/
ReactiveSetCommands setCommands();
/**
* Get {@link ReactiveZSetCommands}.
*
* @return never {@literal null}.
*/
ReactiveZSetCommands zSetCommands();
...
}
同阻塞式接口类似，也是在调用lettuce提供的响应式接口。
0x04 封装
无论是响应式还是阻塞式的接口，Commands方法对用户都不是很友好，所以Spring Data Redis封装了一层Operations接口，用来适配Commands接口里的对应方法(ShortCut)，方便使用者使用。
0x05 问题
目前Spring Data Redis 2.0还是存在一些问题的，比如Reactive命令接口支持不完善，没有对事务、pipeline的支持。
我尝试支持事务，发现一些命令的返回是Mono<Boolean>，但是大多数的redis命令返回不止二值，有可能是多值，比如典型的setIfAbsent()，返回值可能是OK、nil、QUEUED，在阻塞式接口中使用null表示QUEUED，但是如果在响应式接口中返回Mono.empty()，事件就无法发射出去，导致后续操作的失败，这种方案被否。转而想用Mono.error来实现，但是这种方法会有歧义，这个需要再去考虑考虑。