当我的实例刚刚启动时，我无法连接到 redis。

我使用:

runtime: java
env: flex

runtime_config:  
  jdk: openjdk8

我遇到以下异常:

Caused by: redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: connect timed out

RedisConnectionFailureException: Cannot get Jedis connection; nested exception is redis.clients.jedis.exceptions.JedisConnectionException: Could not get a resource from the pool

java.net.SocketTimeoutException: connect timed out

2-3 分钟后，它会顺利

我是否需要在我的代码中添加一些检查或者我应该如何正确修复它？

附注 我也使用 spring boot，配置如下

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

@Bean
JedisConnectionFactory jedisConnectionFactory() {
    // https://cloud.google.com/memorystore/docs/redis/quotas
    RedisStandaloneConfiguration config = new RedisStandaloneConfiguration(redisHost, 6379);
    return new JedisConnectionFactory(config);
}

@Bean
public RedisTemplate<String, Object> redisTemplate(
        @Autowired JedisConnectionFactory jedisConnectionFactory
) {
    RedisTemplate<String, Object> template = new RedisTemplate<>();
    template.setConnectionFactory(jedisConnectionFactory);
    template.setKeySerializer(new StringRedisSerializer());
    template.setValueSerializer(new GenericJackson2JsonRedisSerializer(newObjectMapper()));
    return template;
}

在 pom.xml 中

    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-redis</artifactId>
    <version>2.1.2.RELEASE</version>

最佳答案

我解决这个问题的方法如下:简而言之，我添加了“ping”方法，它尝试从 Redis 设置和获取值；如果可能，则应用程序已准备就绪。

实现:

首先，您需要更新 app.yaml 添加以下内容:

readiness_check:
path: "/readiness_check"
check_interval_sec: 5
timeout_sec: 4
failure_threshold: 2
success_threshold: 2
app_start_timeout_sec: 300

其次，在您的 rest Controller 中:

@GetMapping("/readiness_check")
public ResponseEntity<?> readiness_check() {

    if (!cacheConfig.ping()) {
        return ResponseEntity.notFound().build();
    }

    return ResponseEntity.ok().build();
}

三，类CacheConfig:

public boolean ping() {
    long prefix = System.currentTimeMillis();
    try {
        redisTemplate.opsForValue().set("readiness_check_" + prefix, Boolean.TRUE, 100, TimeUnit.SECONDS);
        Boolean val = (Boolean) redisTemplate.opsForValue().get("readiness_check_" + prefix);
        return Boolean.TRUE.equals(val);
    } catch (Exception e) {
        LOGGER.info("ping failed for " + System.currentTimeMillis());
        return false;
    }
}

附言 另外，如果有人需要 CacheConfig 的完整实现:​​

@Configuration
public class CacheConfig {

    private static final Logger LOGGER = Logger.getLogger(CacheConfig.class.getName());

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

    private final RedisTemplate<String, Object> redisTemplate;

    @Autowired
    public CacheConfig(@Lazy RedisTemplate<String, Object> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    @Bean
    JedisConnectionFactory jedisConnectionFactory(
            @Autowired JedisPoolConfig poolConfig
    ) {
        // https://cloud.google.com/memorystore/docs/redis/quotas
        RedisStandaloneConfiguration config = new RedisStandaloneConfiguration(redisHost, 6379);

        JedisClientConfiguration clientConfig = JedisClientConfiguration
                .builder()
                .usePooling()
                .poolConfig(poolConfig)
                .build();

        return new JedisConnectionFactory(config, clientConfig);
    }

    @Bean
    public RedisTemplate<String, Object> redisTemplate(
            @Autowired JedisConnectionFactory jedisConnectionFactory
    ) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(jedisConnectionFactory);
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(new GenericJackson2JsonRedisSerializer(newObjectMapper()));
        return template;
    }

    /**
     * Example: https://github.com/PengliuIBM/pws_demo/blob/1becdca1bc19320c2742504baa1cada3260f8d93/redisData/src/main/java/com/pivotal/wangyu/study/springdataredis/config/RedisConfig.java
     */
    @Bean
    redis.clients.jedis.JedisPoolConfig jedisPoolConfig() {
        final redis.clients.jedis.JedisPoolConfig poolConfig = new redis.clients.jedis.JedisPoolConfig();

        // Maximum active connections to Redis instance
        poolConfig.setMaxTotal(16);
        // Number of connections to Redis that just sit there and do nothing
        poolConfig.setMaxIdle(16);
        // Minimum number of idle connections to Redis - these can be seen as always open and ready to serve
        poolConfig.setMinIdle(8);

        // Tests whether connection is dead when returning a connection to the pool
        poolConfig.setTestOnBorrow(true);
        // Tests whether connection is dead when connection retrieval method is called
        poolConfig.setTestOnReturn(true);
        // Tests whether connections are dead during idle periods
        poolConfig.setTestWhileIdle(true);

        return poolConfig;
    }

    public boolean ping() {
        long prefix = System.currentTimeMillis();
        try {
            redisTemplate.opsForValue().set("readiness_check_" + prefix, Boolean.TRUE, 100, TimeUnit.SECONDS);
            Boolean val = (Boolean) redisTemplate.opsForValue().get("readiness_check_" + prefix);
            return Boolean.TRUE.equals(val);
        } catch (Exception e) {
            LOGGER.info("ping failed for " + System.currentTimeMillis());
            return false;
        }
    }
}

关于redis - Google Cloud Memory Store(Redis)，实例刚启动时无法连接到redis，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54571060/