import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import com.google.common.collect.ImmutableList;
import com.hazelcast.client.HazelcastClient;
import com.hazelcast.client.config.ClientConfig;
import com.hazelcast.client.config.ClientConnectionStrategyConfig;
import com.hazelcast.client.config.ClientNetworkConfig;
import com.hazelcast.config.DiscoveryConfig;
import com.hazelcast.config.DiscoveryStrategyConfig;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.kubernetes.HazelcastKubernetesDiscoveryStrategyFactory;

@Configuration
@Primary
public class HazelcastConfiguration {

    @Bean
    public HazelcastInstance hazelcastInstance() {
        return HazelcastClient.newHazelcastClient(HazelcastClientConfigFactory.createClientConfig());
    }
}

class HazelcastClientConfigFactory {

    private static final int CONNECTION_ATTEMPT_PERIOD = 2000;

    public static ClientConfig createClientConfig() {

        final ClientConfig config = new ClientConfig();
        config.getConnectionStrategyConfig()
                .setAsyncStart(true)
                .setReconnectMode(ClientConnectionStrategyConfig.ReconnectMode.ASYNC);

        config.setProperty("hazelcast.discovery.enabled", "true");

        final ClientNetworkConfig networkConfig = new ClientNetworkConfig();

        networkConfig.setRedoOperation(false);
        networkConfig.setConnectionAttemptLimit(Integer.MAX_VALUE);
        networkConfig.setConnectionAttemptPeriod(CONNECTION_ATTEMPT_PERIOD);

        final DiscoveryConfig discoveryConfig = new DiscoveryConfig();
        final HazelcastKubernetesDiscoveryStrategyFactory factory = new HazelcastKubernetesDiscoveryStrategyFactory();

        final DiscoveryStrategyConfig strategyConfig = new DiscoveryStrategyConfig(factory);
        strategyConfig.addProperty("service-dns", "hazelcast");
        strategyConfig.addProperty("service-dns-timeout", 10);

        discoveryConfig.setDiscoveryStrategyConfigs(ImmutableList.of(strategyConfig));
        networkConfig.setDiscoveryConfig(discoveryConfig);
        config.setNetworkConfig(networkConfig);

        return config;
    }
}