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.Duration;
-import java.time.ZoneId;
+import java.time.*;
import java.util.*;
import java.util.concurrent.ExecutorService;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReadWriteLock;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
@Slf4j
// private final long[] offsets; Erst mal immer alles neu einlesen
private final boolean[] isShardOwned;
private final Map<UUID, ChatRoom>[] chatRoomMaps;
- private final ReadWriteLock lock = new ReentrantReadWriteLock();
+ private final KafkaLikeShardingStrategy shardingStrategy;
private boolean running;
+ private volatile boolean loadInProgress;
public KafkaChatHomeService(
// }
this.isShardOwned = new boolean[numShards];
this.chatRoomMaps = new Map[numShards];
+ this.shardingStrategy = new KafkaLikeShardingStrategy(numShards);
}
@Override
public void onPartitionsAssigned(Collection<TopicPartition> partitions)
{
- try
- {
- lock.writeLock().lock();
+ loadInProgress = true;
- consumer.endOffsets(partitions).forEach((topicPartition, currentOffset) ->
+ consumer.endOffsets(partitions).forEach((topicPartition, currentOffset) ->
+ {
+ if (!topicPartition.topic().equals(topic))
{
- if (!topicPartition.topic().equals(topic))
- {
- log.warn("Ignoring partition from unwanted topic: {}", topicPartition);
- return;
- }
+ log.warn("Ignoring partition from unwanted topic: {}", topicPartition);
+ return;
+ }
- int partition = topicPartition.partition();
- long unseenOffset = 0; // offsets[partition];
+ int partition = topicPartition.partition();
+ long unseenOffset = 0; // offsets[partition];
- log.info(
- "Loading messages from partition {}: start-offset={} -> current-offset={}",
- partition,
- unseenOffset,
- currentOffset);
+ 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);
- });
+ // TODO: reuse! Nicht immer alles neu laden, sondern erst ab offsets[partition]!
+ consumer.seek(topicPartition, unseenOffset);
+ });
- consumer.resume(partitions);
- }
- finally
- {
- lock.writeLock().unlock();
- }
+ consumer.resume(partitions);
}
@Override
ConsumerRecords<String, MessageTo> records = consumer.poll(Duration.ofMinutes(5));
log.info("Fetched {} messages", records.count());
- for (ConsumerRecord<String, MessageTo> record : records)
+ 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);
+ }
+ }));
+ });
+ }
+
+
@Override
public Mono<ChatRoom> getChatRoom(int shard, UUID id)
{
- if (lock.readLock().tryLock())
+ if (loadInProgress)
{
- try
- {
- return Mono.justOrEmpty(chatRoomMaps[shard].get(id));
- }
- finally
- {
- lock.readLock().unlock();
- }
+ throw new ShardNotOwnedException(shard);
}
else
{
- throw new ShardNotOwnedException(shard);
+ return Mono.justOrEmpty(chatRoomMaps[shard].get(id));
}
}
@Override
public Flux<ChatRoom> getChatRooms(int shard)
{
- if (lock.readLock().tryLock())
+ if (loadInProgress)
{
- try
- {
- return Flux.fromStream(chatRoomMaps[shard].values().stream());
- }
- finally
- {
- lock.readLock().unlock();
- }
+ throw new ShardNotOwnedException(shard);
}
else
{
- throw new ShardNotOwnedException(shard);
+ return Flux.fromStream(chatRoomMaps[shard].values().stream());
}
}
}
import de.juplo.kafka.chat.backend.domain.ChatRoomService;
import de.juplo.kafka.chat.backend.domain.Message;
import de.juplo.kafka.chat.backend.domain.MessageMutationException;
+import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
-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.LocalDateTime;
import java.util.LinkedHashMap;
+import java.util.UUID;
+@RequiredArgsConstructor
@Slf4j
public class KafkaChatRoomService implements ChatRoomService
{
- private final Producer<String, MessageTo> producer;
- private final TopicPartition tp;
+ private final KafkaChatHomeService kafkaChatHomeService;
+ private final UUID chatRoomId;
private final LinkedHashMap<Message.MessageKey, Message> messages = new LinkedHashMap<>();
- public KafkaChatRoomService(
- Producer<String, MessageTo> producer,
- TopicPartition tp)
- {
- this.producer = producer;
- this.tp = tp;
- }
-
-
@Override
- synchronized public Mono<Message> persistMessage(
+ public Mono<Message> persistMessage(
Message.MessageKey key,
LocalDateTime timestamp,
String text)
{
- return Mono.create(sink ->
- {
- ProducerRecord<String, MessageTo> record =
- new ProducerRecord<>(
- tp.topic(),
- tp.partition(),
- timestamp.toEpochSecond(zoneOffset),
- chatRoomId.toString(),
- MessageTo.of(key.getUsername(), key.getMessageId(), text));
-
- producer.send(record, ((metadata, exception) ->
- {
- if (metadata != null)
- {
- // On successful send
- {
- // Emit new message
- Message message = new Message(key, metadata.offset(), timestamp, text);
- kafkaChatRoomService.addMessage(message);
- }
-
- sink.success();
- }
- else
- {
- // On send-failure
- sink.error(exception);
- }
- }));
- });
+ return kafkaChatHomeService.sendMessage(chatRoomId, key, timestamp, text);
}
/**
projects / demos / kafka / chat / commitdiff