import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.errors.RecordDeserializationException;
+import org.apache.kafka.common.errors.WakeupException;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import java.time.*;
import java.util.*;
-import java.util.concurrent.ExecutorService;
+import java.util.stream.IntStream;
@Slf4j
public class KafkaChatHomeService implements ChatHomeService, Runnable, ConsumerRebalanceListener
{
- 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 int numShards;
private final boolean[] isShardOwned;
- private final Map<UUID, ChatRoom>[] chatRoomMaps;
+ private final long[] currentOffset;
+ private final long[] nextOffset;
+ private final Map<UUID, ChatRoom>[] chatrooms;
private final KafkaLikeShardingStrategy shardingStrategy;
private boolean running;
public KafkaChatHomeService(
- ExecutorService executorService,
Consumer<String, MessageTo> consumer,
Producer<String, MessageTo> producer,
String topic,
int numShards)
{
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.numShards = numShards;
this.isShardOwned = new boolean[numShards];
- this.chatRoomMaps = new Map[numShards];
+ this.currentOffset = new long[numShards];
+ this.nextOffset = new long[numShards];
+ this.chatrooms = new Map[numShards];
this.shardingStrategy = new KafkaLikeShardingStrategy(numShards);
}
@Override
public void onPartitionsAssigned(Collection<TopicPartition> partitions)
{
+ log.info("Newly assigned partitions! Pausing normal operations...");
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];
+ isShardOwned[partition] = true;
+ this.currentOffset[partition] = currentOffset;
log.info(
- "Loading messages from partition {}: start-offset={} -> current-offset={}",
+ "Partition assigned: {} - loading messages: next={} -> current={}",
partition,
- unseenOffset,
+ nextOffset[partition],
currentOffset);
- // TODO: reuse! Nicht immer alles neu laden, sondern erst ab offsets[partition]!
- consumer.seek(topicPartition, unseenOffset);
+ consumer.seek(topicPartition, nextOffset[partition]);
});
consumer.resume(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...?
+ isShardOwned[partition] = false;
+ log.info("Partition revoked: {} - next={}", partition, nextOffset[partition]);
});
- log.info("Revoked partitions: {}", partitions);
}
@Override
public void onPartitionsLost(Collection<TopicPartition> partitions)
{
+ log.warn("Lost partitions: {}, partitions");
// TODO: Muss auf den Verlust anders reagiert werden?
onPartitionsRevoked(partitions);
}
running = true;
- try
+ while (running)
{
- while (running)
+ try
{
ConsumerRecords<String, MessageTo> records = consumer.poll(Duration.ofMinutes(5));
log.info("Fetched {} messages", records.count());
if (loadInProgress)
{
- for (ConsumerRecord<String, MessageTo> record : records)
+ loadMessages(records);
+
+ if (isLoadingCompleted())
{
- 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().
+ log.info("Loading of messages completed! Pausing all owned partitions...");
+ pauseAllOwnedPartions();
+ log.info("Resuming normal operations...");
+ loadInProgress = false;
}
}
else
{
if (!records.isEmpty())
{
- throw new IllegalStateException("All owned partions should be paused, when no load is in progress!");
+ throw new IllegalStateException("All owned partitions should be paused, when no load is in progress!");
}
}
}
+ catch (WakeupException e)
+ {
+ }
+ catch (RecordDeserializationException e)
+ {
+ }
+ }
+ }
+
+ void loadMessages(ConsumerRecords<String, MessageTo> records)
+ {
+ for (ConsumerRecord<String, MessageTo> record : records)
+ {
+ nextOffset[record.partition()] = record.offset() + 1;
+ UUID chatRoomId = UUID.fromString(record.key());
+ MessageTo messageTo = record.value();
+
+ Message.MessageKey key = Message.MessageKey.of(messageTo.getUser(), messageTo.getId());
+
+ Instant instant = Instant.ofEpochSecond(record.timestamp());
+ LocalDateTime timestamp = LocalDateTime.ofInstant(instant, zoneId);
+
+ Message message = new Message(key, record.offset(), timestamp, messageTo.getText());
+
+ ChatRoom chatRoom = chatrooms[record.partition()].get(chatRoomId);
+ KafkaChatRoomService kafkaChatRoomService =
+ (KafkaChatRoomService) chatRoom.getChatRoomService();
+
+ kafkaChatRoomService.persistMessage(message);
}
}
+ boolean isLoadingCompleted()
+ {
+ return IntStream
+ .range(0, numShards)
+ .filter(shard -> isShardOwned[shard])
+ .mapToObj(shard -> nextOffset[shard] >= currentOffset[shard])
+ .collect(
+ () -> Boolean.TRUE,
+ (acc, v) -> Boolean.valueOf(acc && v),
+ (a, b) -> Boolean.valueOf(a && b));
+ }
+
+ void pauseAllOwnedPartions()
+ {
+ consumer.pause(IntStream
+ .range(0, numShards)
+ .filter(shard -> isShardOwned[shard])
+ .mapToObj(shard -> new TopicPartition(topic, shard))
+ .toList());
+ }
+
Mono<Message> sendMessage(
UUID chatRoomId,
Message.MessageKey key,
}
+ public void putChatRoom(ChatRoom chatRoom)
+ {
+ // TODO: Nachricht senden!
+ chatrooms[chatRoom.getShard()].put(chatRoom.getId(), chatRoom);
+ }
+
@Override
public Mono<ChatRoom> getChatRoom(int shard, UUID id)
{
}
else
{
- return Mono.justOrEmpty(chatRoomMaps[shard].get(id));
+ return Mono.justOrEmpty(chatrooms[shard].get(id));
}
}
}
else
{
- return Flux.fromStream(chatRoomMaps[shard].values().stream());
+ return Flux.fromStream(chatrooms[shard].values().stream());
}
}
}
projects / demos / kafka / chat / blobdiff