pl.allegro.tech.hermes.infrastructure.zookeeper.ZookeeperMessagePreviewRepository Maven / Gradle / Ivy

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Fast and reliable message broker built on top of Kafka.

There is a newer version: 2.7.0

package pl.allegro.tech.hermes.infrastructure.zookeeper;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.curator.framework.CuratorFramework;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import pl.allegro.tech.hermes.api.TopicName;
import pl.allegro.tech.hermes.common.exception.InternalProcessingException;
import pl.allegro.tech.hermes.domain.topic.preview.MessagePreview;
import pl.allegro.tech.hermes.domain.topic.preview.MessagePreviewRepository;
import pl.allegro.tech.hermes.domain.topic.preview.TopicsMessagesPreview;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

import static java.lang.String.format;

public class ZookeeperMessagePreviewRepository extends ZookeeperBasedRepository implements MessagePreviewRepository {

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

    public ZookeeperMessagePreviewRepository(CuratorFramework zookeeper, ObjectMapper mapper, ZookeeperPaths paths) {
        super(zookeeper, mapper, paths);
    }

    @Override
    public List loadPreview(TopicName topicName) {
        try {
            return Optional.of(paths.topicPreviewPath(topicName))
                    .filter(this::pathExists)
                    .flatMap(p -> readFrom(p, new TypeReference>() {}, true))
                    .orElseGet(ArrayList::new);
        } catch (Exception e) {
            throw new InternalProcessingException(
                    format("Could not read latest preview message for topic: %s.", topicName.qualifiedName()), e);
        }
    }


    @Override
    public void persist(TopicsMessagesPreview topicsMessagesPreview) {
        for (TopicName topic : topicsMessagesPreview.topics()) {
            persistMessage(topic, topicsMessagesPreview.previewOf(topic));
        }
    }

    private void persistMessage(TopicName topic, List messages) {
        logger.debug("Persisting {} messages for preview of topic: {}", messages.size(), topic.qualifiedName());
        try {
            if (pathExists(paths.topicPath(topic))) {
                String previewPath = paths.topicPreviewPath(topic);
                ensurePathExists(previewPath);
                overwrite(previewPath, messages);
            }
        } catch (Exception exception) {
            logger.warn(
                    format("Could not log preview messages for topic: %s", topic.qualifiedName()),
                    exception
            );
        }
    }
}