fix: Slow RabbitMQ message polling

Configurable RabbitMQ polling in order that more messages can be obtained from the queue during a poll.

Fixes #8445

application/src/main/resources/thingsboard.yml

@@ -1117,6 +1117,7 @@ queue:
     automatic_recovery_enabled: "${TB_QUEUE_RABBIT_MQ_AUTOMATIC_RECOVERY_ENABLED:false}"
     connection_timeout: "${TB_QUEUE_RABBIT_MQ_CONNECTION_TIMEOUT:60000}"
     handshake_timeout: "${TB_QUEUE_RABBIT_MQ_HANDSHAKE_TIMEOUT:10000}"
+    max_poll_messages: "${TB_QUEUE_RABBIT_MQ_MAX_POLL_MESSAGES:1}"
     queue-properties:
       rule-engine: "${TB_QUEUE_RABBIT_MQ_RE_QUEUE_PROPERTIES:x-max-length-bytes:1048576000;x-message-ttl:604800000}"
       core: "${TB_QUEUE_RABBIT_MQ_CORE_QUEUE_PROPERTIES:x-max-length-bytes:1048576000;x-message-ttl:604800000}"

common/queue/src/main/java/org/thingsboard/server/queue/rabbitmq/TbRabbitMqConsumerTemplate.java

@@ -20,6 +20,8 @@ import com.google.protobuf.InvalidProtocolBufferException;
 import com.rabbitmq.client.Channel;
 import com.rabbitmq.client.Connection;
 import com.rabbitmq.client.GetResponse;
+import java.util.ArrayList;
+import java.util.Collection;
 import lombok.extern.slf4j.Slf4j;
 import org.thingsboard.server.common.msg.queue.TopicPartitionInfo;
 import org.thingsboard.server.queue.TbQueueAdmin;
@@ -31,7 +33,6 @@ import org.thingsboard.server.queue.common.DefaultTbQueueMsg;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.TimeoutException;
 import java.util.stream.Collectors;
@@ -44,6 +45,7 @@ public class TbRabbitMqConsumerTemplate<T extends TbQueueMsg> extends AbstractTb
     private final TbQueueMsgDecoder<T> decoder;
     private final Channel channel;
     private final Connection connection;
+    private final int maxPollMessages;
 
     private volatile Set<String> queues;
 
@@ -51,6 +53,7 @@ public class TbRabbitMqConsumerTemplate<T extends TbQueueMsg> extends AbstractTb
         super(topic);
         this.admin = admin;
         this.decoder = decoder;
+        this.maxPollMessages = rabbitMqSettings.getMaxPollMessages();
         try {
             connection = rabbitMqSettings.getConnectionFactory().newConnection();
         } catch (IOException | TimeoutException e) {
@@ -70,18 +73,33 @@ public class TbRabbitMqConsumerTemplate<T extends TbQueueMsg> extends AbstractTb
     protected List<GetResponse> doPoll(long durationInMillis) {
         List<GetResponse> result = queues.stream()
                 .map(queue -> {
+                    List<GetResponse> messages = new ArrayList<>();
+                    for (int i = 0; i < maxPollMessages; i++) {
+                        GetResponse response = doQueuePoll(queue);
+                        if (response == null) {
+                            break;
+                        }
+                        messages.add(response);
+                    }
+                    return messages;
+                })
+                .filter(r -> !r.isEmpty())
+                .flatMap(Collection::stream)
+                .collect(Collectors.toList());
+        if (result.size() > 0) {
+            return result;
+        } else {
+            return Collections.emptyList();
+        }
+    }
+
+    protected GetResponse doQueuePoll(String queue) {
         try {
             return channel.basicGet(queue, false);
         } catch (IOException e) {
             log.error("Failed to get messages from queue: [{}]", queue);
             throw new RuntimeException("Failed to get messages from queue.", e);
         }
-                }).filter(Objects::nonNull).collect(Collectors.toList());
-        if (result.size() > 0) {
-            return result;
-        } else {
-            return Collections.emptyList();
-        }
     }
 
     @Override

common/queue/src/main/java/org/thingsboard/server/queue/rabbitmq/TbRabbitMqSettings.java

@@ -47,6 +47,8 @@ public class TbRabbitMqSettings {
     private int connectionTimeout;
     @Value("${queue.rabbitmq.handshake_timeout:}")
     private int handshakeTimeout;
+    @Value("${queue.rabbitmq.max_poll_messages:1}")
+    private int maxPollMessages;
 
     private ConnectionFactory connectionFactory;
 

common/queue/src/test/java/org/thingsboard/server/queue/rabbitmq/TbRabbitMqConsumerTemplateTest.java

@@ -0,0 +1,128 @@
+/**
+ * Copyright © 2016-2023 The Thingsboard Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.thingsboard.server.queue.rabbitmq;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.rabbitmq.client.Channel;
+import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.ConnectionFactory;
+import com.rabbitmq.client.GetResponse;
+import java.nio.charset.StandardCharsets;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.thingsboard.server.common.msg.queue.TopicPartitionInfo;
+import org.thingsboard.server.queue.TbQueueAdmin;
+import org.thingsboard.server.queue.TbQueueMsgDecoder;
+import org.thingsboard.server.queue.common.DefaultTbQueueMsg;
+
+@ExtendWith(MockitoExtension.class)
+class TbRabbitMqConsumerTemplateTest {
+
+  private static final String TOPIC = "some-topic";
+
+  @Mock
+  private TbQueueAdmin admin;
+
+  @Mock
+  private ConnectionFactory connectionFactory;
+
+  @Mock
+  private TbQueueMsgDecoder<DefaultTbQueueMsg> decoder;
+
+  @Mock
+  private Connection connection;
+
+  @Mock
+  private Channel channel;
+
+  @Mock
+  private TopicPartitionInfo partition;
+
+  @Mock
+  private GetResponse getResponse;
+
+  private TbRabbitMqConsumerTemplate<DefaultTbQueueMsg> consumer;
+
+  private void setUpConsumerWithMaxPollMessages(int maxPollMessages) throws Exception {
+    when(connectionFactory.newConnection()).thenReturn(connection);
+    when(connection.createChannel()).thenReturn(channel);
+    TbRabbitMqSettings settings = new TbRabbitMqSettings();
+    settings.setMaxPollMessages(maxPollMessages);
+    settings.setConnectionFactory(connectionFactory);
+
+    consumer = new TbRabbitMqConsumerTemplate<>(admin, settings, TOPIC, decoder);
+    when(partition.getFullTopicName()).thenReturn(TOPIC);
+    consumer.subscribe(Set.of(partition));
+  }
+
+  @Test
+  void pollWithMax5PollMessagesReturnsEmptyListIfNoMessages() throws Exception {
+    setUpConsumerWithMaxPollMessages(5);
+    when(channel.basicGet(anyString(), anyBoolean())).thenReturn(null);
+
+    assertThat(consumer.poll(0L)).isEmpty();
+
+    verify(channel).basicGet(anyString(), anyBoolean());
+  }
+
+  @Test
+  void pollWithMax5PollMessagesReturns5MessagesIfQueueContains5() throws Exception {
+    setUpConsumerWithMaxPollMessages(5);
+    when(getResponse.getBody()).thenReturn(newMessageBody());
+    when(channel.basicGet(anyString(), anyBoolean())).thenReturn(getResponse);
+
+    assertThat(consumer.poll(0L)).hasSize(5);
+
+    verify(channel, times(5)).basicGet(anyString(), anyBoolean());
+  }
+
+  @Test
+  void pollWithMax1PollMessageReturns1MessageIfQueueContainsMore() throws Exception {
+    setUpConsumerWithMaxPollMessages(1);
+    when(getResponse.getBody()).thenReturn(newMessageBody());
+    when(channel.basicGet(anyString(), anyBoolean())).thenReturn(getResponse);
+
+    assertThat(consumer.poll(0L)).hasSize(1);
+
+    verify(channel).basicGet(anyString(), anyBoolean());
+  }
+
+  @Test
+  void pollWithMax3PollMessagesReturns2MessagesIfQueueContains2() throws Exception {
+    setUpConsumerWithMaxPollMessages(3);
+    when(getResponse.getBody()).thenReturn(newMessageBody());
+    when(channel.basicGet(anyString(), anyBoolean())).thenReturn(getResponse, getResponse, null);
+
+    assertThat(consumer.poll(0L)).hasSize(2);
+
+    verify(channel, times(3)).basicGet(anyString(), anyBoolean());
+  }
+
+  private byte[] newMessageBody() {
+    return ("{\"key\": \"" + UUID.randomUUID() + "\"}").getBytes(StandardCharsets.UTF_8);
+  }
+
+}