Spring Redis Error Handle

问题:

I am using Spring + Redis as my cache component in the new project. The spring config xml file is:

<!-- Jedis Connection --> 
<bean id="jedisConnectionFactory" 
    class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
    p:host-name="${redis.ip}" p:port="${redis.port}" p:use-pool="${redis.use-pool}" />

<!-- Redis Template -->
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
    <property name="connectionFactory" ref="jedisConnectionFactory" />
    <property name="keySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
    </property>
    <property name="valueSerializer">  
        <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer" />
    </property> 
</bean>

<bean id="cacheManager" class="org.springframework.data.redis.cache.RedisCacheManager" c:template-ref="redisTemplate"/>

<cache:annotation-driven mode="proxy" proxy-target-class="true" cache-manager="cacheManager" />

The usage is

    @Cacheable(value = "cacheManager", key="#userId")
public User getUser(String userId) {
    System.out.println("execute==");
    return userAdminMapper.getUser(userId);
}

My test case is:

@Test
public void testCacheUser2() {
    String id = "test";
    User user = userService.getUser(id);
    System.out.println(user);
    user.setUserCreateDate(new Date());
    userService.updateUser(user);
    User user2 = userService.getUser(id);
    System.out.println(user2);
    User user3 = userService.getUser(id);
    System.out.println(user3);
}

If the Redis server is running, the code is running correctly. But my question is if I shutdown the Redis server, it will throw the exception:

org.springframework.data.redis.RedisConnectionFailureException: Cannot get Jedis connection; nested exception is redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused: connect
    at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.fetchJedisConnector(JedisConnectionFactory.java:140)
    at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:229)
    at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:57)
    at org.springframework.data.redis.core.RedisConnectionUtils.doGetConnection(RedisConnectionUtils.java:128)
    at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:91)
    at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:78)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:177)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:152)
    at org.springframework.data.redis.cache.RedisCache.get(RedisCache.java:87)
    at org.springframework.cache.interceptor.CacheAspectSupport.findInCaches(CacheAspectSupport.java:297)
    at org.springframework.cache.interceptor.CacheAspectSupport.findInAnyCaches(CacheAspectSupport.java:287)
    at org.springframework.cache.interceptor.CacheAspectSupport.collectPutRequests(CacheAspectSupport.java:266)
    at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:199)
    at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:178)
    at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:60)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:644)
    at sg.infolab.common.admin.service.impl.UserServiceImpl$$EnhancerBySpringCGLIB$$c7f982a7.getUser(<generated>)
    at sg.infolab.admin.test.RedisServiceTest.testCacheUser2(RedisServiceTest.java:35)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:232)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:175)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused: connect
    at redis.clients.jedis.Connection.connect(Connection.java:150)
    at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:71)
    at redis.clients.jedis.BinaryJedis.connect(BinaryJedis.java:1783)
    at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.fetchJedisConnector(JedisConnectionFactory.java:137)
    ... 50 more
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
    at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
    at java.net.Socket.connect(Socket.java:529)
    at redis.clients.jedis.Connection.connect(Connection.java:144)
    ... 53 more

I want to ask if the client couldn't connect Redis Server, why will it throw exception? Can we config the scenario like this -- if the cache layer(Redis Server) cannot connect(maybe it is crashed or network is not up), it should directly connect to database and fetch data.

回答1:

I had the very same problem. I'm developing some data services against a database, using Redis as the cache store by way of Spring Caching annotations. If the Redis server becomes unavailable, I want the services to continue to operate as if uncached, rather than throwing exceptions.

At first I tried a custom CacheErrorHandler, a mechanism provided by Spring. It didn't quite work, because it only handles RuntimeExceptions, and still lets things like java.net.ConnectException blow things up.

In the end what I did is extend RedisTemplate, overriding a few execute() methods so that they log warnings instead of propagating exceptions. It seems like a bit of a hack, and I might have overridden too few execute() methods or too many, but it works like a charm in all my test cases.

There's an important operational aspect to this approach, though. If the Redis server becomes unavailable you must flush it (clean out the entries) before making it available again. Otherwise there's a chance that you might start retrieving cache entries that have incorrect data because of updates that occurred in the meantime.

Below is the source. Feel free to use it. I hope it helps.

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.SessionCallback;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.data.redis.serializer.RedisSerializer;


/**
 * An extension of RedisTemplate that logs exceptions instead of letting them propagate.
 * If the Redis server is unavailable, cache operations are always a "miss" and data is fetched from the database.
 */
public class LoggingRedisTemplate<K, V> extends RedisTemplate<K, V> {

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


    @Override
    public <T> T execute(final RedisCallback<T> action, final boolean exposeConnection, final boolean pipeline) {
        try {
            return super.execute(action, exposeConnection, pipeline);
        }
        catch(final Throwable t) {
            logger.warn("Error executing cache operation: {}", t.getMessage());
            return null;
        }
    }


    @Override
    public <T> T execute(final RedisScript<T> script, final List<K> keys, final Object... args) {
        try {
            return super.execute(script, keys, args);
        }
        catch(final Throwable t) {
            logger.warn("Error executing cache operation: {}", t.getMessage());
            return null;
        }
    }


    @Override
    public <T> T execute(final RedisScript<T> script, final RedisSerializer<?> argsSerializer, final RedisSerializer<T> resultSerializer, final List<K> keys, final Object... args) {
        try {
            return super.execute(script, argsSerializer, resultSerializer, keys, args);
        }
        catch(final Throwable t) {
            logger.warn("Error executing cache operation: {}", t.getMessage());
            return null;
        }
    }


    @Override
    public <T> T execute(final SessionCallback<T> session) {
        try {
            return super.execute(session);
        }
        catch(final Throwable t) {
            logger.warn("Error executing cache operation: {}", t.getMessage());
            return null;
        }
    }
}

回答2:

I have the same error. And I managed to solve it by adding two things:

• timeout for connectionFactory
• error handler

@Configuration
@ConditionalOnProperty(name = "redis.enabled", havingValue = "true")
@EnableCaching
public class RedisCacheConfig extends CachingConfigurerSupport implements CachingConfigurer {

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

    @Value("${redis.port}")
    private Integer port;

    @Value("${redis.expiration.timeout}")
    private Integer expirationTimeout;

    @Bean
    public JedisConnectionFactory redisConnectionFactory() {
        JedisConnectionFactory redisConnectionFactory = new JedisConnectionFactory();
        redisConnectionFactory.setHostName(host);
        redisConnectionFactory.setPort(port);
        redisConnectionFactory.setTimeout(10);
        return redisConnectionFactory;
    }

    @Bean
    public RedisTemplate<String, Set<String>> redisTemplate(@Autowired RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Set<String>> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        return redisTemplate;
    }

    @Bean
    public CacheManager cacheManager(@Autowired RedisTemplate redisTemplate) {
        RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate);
        cacheManager.setDefaultExpiration(expirationTimeout);
        return cacheManager;
    }

    @Override
    public CacheErrorHandler errorHandler() {
        return new RedisCacheErrorHandler();
    }

    @Slf4j
    public static class RedisCacheErrorHandler implements CacheErrorHandler {

        @Override
        public void handleCacheGetError(RuntimeException exception, Cache cache, Object key) {
            log.info("Unable to get from cache " + cache.getName() + " : " + exception.getMessage());
        }

        @Override
        public void handleCachePutError(RuntimeException exception, Cache cache, Object key, Object value) {
            log.info("Unable to put into cache " + cache.getName() + " : " + exception.getMessage());
        }

        @Override
        public void handleCacheEvictError(RuntimeException exception, Cache cache, Object key) {
            log.info("Unable to evict from cache " + cache.getName() + " : " + exception.getMessage());
        }

        @Override
        public void handleCacheClearError(RuntimeException exception, Cache cache) {
            log.info("Unable to clean cache " + cache.getName() + " : " + exception.getMessage());
        }
    }
}