NEU

[demos/kafka/chat] / src / main / java / de / juplo / kafka / chat / backend / persistence / kafka / KafkaChatHomeService.java

diff --git a/src/main/java/de/juplo/kafka/chat/backend/persistence/kafka/KafkaChatHomeService.java b/src/main/java/de/juplo/kafka/chat/backend/persistence/kafka/KafkaChatHomeService.java
index a95df54..5133d1a 100644 (file)
--- a/src/main/java/de/juplo/kafka/chat/backend/persistence/kafka/KafkaChatHomeService.java
+++ b/src/main/java/de/juplo/kafka/chat/backend/persistence/kafka/KafkaChatHomeService.java
@@ -2,21 +2,27 @@ package de.juplo.kafka.chat.backend.persistence.kafka;
 
 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.ZoneId;
+import java.time.*;
 import java.util.*;
 import java.util.concurrent.ExecutorService;
 
 
 @Slf4j
-public class KafkaChatHomeService implements ChatHomeService, ConsumerRebalanceListener
+public class KafkaChatHomeService implements ChatHomeService, Runnable, ConsumerRebalanceListener
 {
   private final ExecutorService executorService;
   private final Consumer<String, MessageTo> consumer;
@@ -24,8 +30,12 @@ public class KafkaChatHomeService implements ChatHomeService, ConsumerRebalanceL
   private final String topic;
   private final ZoneId zoneId;
   // private final long[] offsets; Erst mal immer alles neu einlesen
-  private final ChatHomeLoader[] chatHomeLoaders;
+  private final boolean[] isShardOwned;
   private final Map<UUID, ChatRoom>[] chatRoomMaps;
+  private final KafkaLikeShardingStrategy shardingStrategy;
+
+  private boolean running;
+  private volatile boolean loadInProgress;
 
 
   public KafkaChatHomeService(
@@ -47,14 +57,17 @@ public class KafkaChatHomeService implements ChatHomeService, ConsumerRebalanceL
     // {
     //   this.offsets[i] = 0l;
     // }
-    this.chatHomeLoaders = new ChatHomeLoader[numShards];
+    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))
@@ -74,11 +87,9 @@ public class KafkaChatHomeService implements ChatHomeService, ConsumerRebalanceL
 
       // TODO: reuse! Nicht immer alles neu laden, sondern erst ab offsets[partition]!
       consumer.seek(topicPartition, unseenOffset);
-      chatHomeLoaders[partition] = new ChatHomeLoader(
-          producer,
-          currentOffset,
-          zoneId);
     });
+
+    consumer.resume(partitions);
   }
 
   @Override
@@ -105,15 +116,113 @@ public class KafkaChatHomeService implements ChatHomeService, ConsumerRebalanceL
     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);
+        }
+      }));
+    });
+  }
+
+
   @Override
   public Mono<ChatRoom> getChatRoom(int shard, UUID id)
   {
-    return Mono.justOrEmpty(chatRoomMaps[shard].get(id));
+    if (loadInProgress)
+    {
+      throw new ShardNotOwnedException(shard);
+    }
+    else
+    {
+      return Mono.justOrEmpty(chatRoomMaps[shard].get(id));
+    }
   }
 
   @Override
   public Flux<ChatRoom> getChatRooms(int shard)
   {
-    return Flux.fromStream(chatRoomMaps[shard].values().stream());
+    if (loadInProgress)
+    {
+      throw new ShardNotOwnedException(shard);
+    }
+    else
+    {
+      return Flux.fromStream(chatRoomMaps[shard].values().stream());
+    }
   }
 }