import de.juplo.kafka.chat.backend.domain.ChatHomeService;
import de.juplo.kafka.chat.backend.domain.ChatRoom;
-import de.juplo.kafka.chat.backend.domain.Message;
import de.juplo.kafka.chat.backend.domain.ShardNotOwnedException;
-import de.juplo.kafka.chat.backend.persistence.KafkaLikeShardingStrategy;
import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.Consumer;
-import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
-import org.apache.kafka.clients.consumer.ConsumerRecord;
-import org.apache.kafka.clients.consumer.ConsumerRecords;
-import org.apache.kafka.clients.producer.Producer;
-import org.apache.kafka.clients.producer.ProducerRecord;
-import org.apache.kafka.common.TopicPartition;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
-import java.time.*;
import java.util.*;
-import java.util.concurrent.ExecutorService;
@Slf4j
-public class KafkaChatHomeService implements ChatHomeService, Runnable, ConsumerRebalanceListener
+public class KafkaChatHomeService implements ChatHomeService
{
- private final ExecutorService executorService;
- private final Consumer<String, MessageTo> consumer;
- private final Producer<String, MessageTo> producer;
- private final String topic;
- private final ZoneId zoneId;
- // private final long[] offsets; Erst mal immer alles neu einlesen
- private final boolean[] isShardOwned;
- private final Map<UUID, ChatRoom>[] chatRoomMaps;
- private final KafkaLikeShardingStrategy shardingStrategy;
+ private final ChatMessageChannel chatMessageChanel;
- private boolean running;
- private volatile boolean loadInProgress;
-
- public KafkaChatHomeService(
- ExecutorService executorService,
- Consumer<String, MessageTo> consumer,
- Producer<String, MessageTo> producer,
- String topic,
- ZoneId zoneId,
- int numShards)
+ public KafkaChatHomeService(ChatMessageChannel chatMessageChannel)
{
log.debug("Creating KafkaChatHomeService");
- this.executorService = executorService;
- this.consumer = consumer;
- this.producer = producer;
- this.topic = topic;
- this.zoneId = zoneId;
- // this.offsets = new long[numShards];
- // for (int i=0; i< numShards; i++)
- // {
- // this.offsets[i] = 0l;
- // }
- this.isShardOwned = new boolean[numShards];
- this.chatRoomMaps = new Map[numShards];
- this.shardingStrategy = new KafkaLikeShardingStrategy(numShards);
- }
-
-
- @Override
- public void onPartitionsAssigned(Collection<TopicPartition> partitions)
- {
- loadInProgress = true;
-
- consumer.endOffsets(partitions).forEach((topicPartition, currentOffset) ->
- {
- if (!topicPartition.topic().equals(topic))
- {
- log.warn("Ignoring partition from unwanted topic: {}", topicPartition);
- return;
- }
-
- int partition = topicPartition.partition();
- long unseenOffset = 0; // offsets[partition];
-
- log.info(
- "Loading messages from partition {}: start-offset={} -> current-offset={}",
- partition,
- unseenOffset,
- currentOffset);
-
- // TODO: reuse! Nicht immer alles neu laden, sondern erst ab offsets[partition]!
- consumer.seek(topicPartition, unseenOffset);
- });
-
- consumer.resume(partitions);
- }
-
- @Override
- public void onPartitionsRevoked(Collection<TopicPartition> partitions)
- {
- partitions.forEach(topicPartition ->
- {
- if (!topicPartition.topic().equals(topic))
- {
- log.warn("Ignoring partition from unwanted topic: {}", topicPartition);
- return;
- }
-
- int partition = topicPartition.partition();
- // long unseenOffset = offsets[partition]; TODO: Offset merken...?
- });
- log.info("Revoked partitions: {}", partitions);
- }
-
- @Override
- public void onPartitionsLost(Collection<TopicPartition> partitions)
- {
- // TODO: Muss auf den Verlust anders reagiert werden?
- onPartitionsRevoked(partitions);
- }
-
- @Override
- public void run()
- {
- consumer.subscribe(List.of(topic));
-
- running = true;
-
- try
- {
- while (running)
- {
- ConsumerRecords<String, MessageTo> records = consumer.poll(Duration.ofMinutes(5));
- log.info("Fetched {} messages", records.count());
-
- if (loadInProgress)
- {
- for (ConsumerRecord<String, MessageTo> record : records)
- {
- UUID chatRoomId = UUID.fromString(record.key());
- MessageTo messageTo = record.value();
- ChatRoom chatRoom = chatRoomMaps[record.partition()].get(chatRoomId);
- Mono<Message> result = chatRoom.addMessage(
- messageTo.getId(),
- messageTo.getUser(),
- messageTo.getText());
- result.block().
- }
- }
- else
- {
- if (!records.isEmpty())
- {
- throw new IllegalStateException("All owned partions should be paused, when no load is in progress!");
- }
- }
- }
- }
- }
-
- Mono<Message> sendMessage(
- UUID chatRoomId,
- Message.MessageKey key,
- LocalDateTime timestamp,
- String text)
- {
- int shard = this.shardingStrategy.selectShard(chatRoomId);
- TopicPartition tp = new TopicPartition(topic, shard);
- ZonedDateTime zdt = ZonedDateTime.of(timestamp, zoneId);
- return Mono.create(sink ->
- {
- ProducerRecord<String, MessageTo> record =
- new ProducerRecord<>(
- tp.topic(),
- tp.partition(),
- zdt.toEpochSecond(),
- chatRoomId.toString(),
- MessageTo.of(key.getUsername(), key.getMessageId(), text));
-
- producer.send(record, ((metadata, exception) ->
- {
- if (metadata != null)
- {
- // On successful send
- Message message = new Message(key, metadata.offset(), timestamp, text);
- log.info("Successfully send message {}", message);
- sink.success(message);
- }
- else
- {
- // On send-failure
- log.error(
- "Could not send message for chat-room={}, key={}, timestamp={}, text={}: {}",
- chatRoomId,
- key,
- timestamp,
- text,
- exception);
- sink.error(exception);
- }
- }));
- });
+ this.chatMessageChanel = chatMessageChannel;
}
@Override
public Mono<ChatRoom> getChatRoom(int shard, UUID id)
{
- if (loadInProgress)
+ if (chatMessageChanel.isLoadInProgress())
{
throw new ShardNotOwnedException(shard);
}
else
{
- return Mono.justOrEmpty(chatRoomMaps[shard].get(id));
+ return chatMessageChanel.getChatRoom(shard, id);
}
}
@Override
public Flux<ChatRoom> getChatRooms(int shard)
{
- if (loadInProgress)
+ if (chatMessageChanel.isLoadInProgress())
{
throw new ShardNotOwnedException(shard);
}
else
{
- return Flux.fromStream(chatRoomMaps[shard].values().stream());
+ return chatMessageChanel.getChatRooms(shard);
}
}
}
projects / demos / kafka / chat / blobdiff