Race condition in JedisClusterTopologyProvider

[velna]

JedisClusterTopologyProvider use a cache object to optimize performace on frequent cluster requests, but the time value is updated before the cache object, there is a race condition that the old cache including the invalid cluster topology might get returned, which will result in a ClusterCommandExecutionFailureException: Could not get a resource from th pool.

	public ClusterTopology getTopology() {

		if (cached != null && shouldUseCachedValue()) {
			return cached;
		}

		Map<String, Exception> errors = new LinkedHashMap<>();

		List<Entry<String, ConnectionPool>> list = new ArrayList<>(cluster.getClusterNodes().entrySet());

		Collections.shuffle(list);

		for (Entry<String, ConnectionPool> entry : list) {

			try (Connection connection = entry.getValue().getResource()) {

				time = System.currentTimeMillis();  // time value is updated before cached object

				Set<RedisClusterNode> nodes = Converters.toSetOfRedisClusterNodes(new Jedis(connection).clusterNodes());

				cached = new ClusterTopology(nodes);

				return cached;

			} catch (Exception ex) {
				errors.put(entry.getKey(), ex);
			}
		}

		StringBuilder stringBuilder = new StringBuilder();

		for (Entry<String, Exception> entry : errors.entrySet()) {
			stringBuilder.append(String.format("\r\n\t- %s failed: %s", entry.getKey(), entry.getValue().getMessage()));
		}

		throw new ClusterStateFailureException(
				"Could not retrieve cluster information; CLUSTER NODES returned with error" + stringBuilder);
	}