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/*-
* ============LICENSE_START=======================================================
* Simulator
* ================================================================================
* Copyright (C) 2019 Nokia. All rights reserved.
* ================================================================================
* 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.
* ============LICENSE_END=========================================================
*/
package org.onap.netconfsimulator.kafka;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.common.TopicPartition;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.stereotype.Service;
import java.time.Duration;
import java.time.Instant;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.NoSuchElementException;
@Slf4j
@Service
public class StoreService {
private static final String CONFIG_TOPIC = "config";
private static final long CONSUMING_DURATION_IN_MS = 5000;
private ConsumerFactory<String, String> consumerFactory;
static final List<String> TOPICS_TO_SUBSCRIBE = Collections.singletonList(CONFIG_TOPIC);
@Autowired
StoreService(ConsumerFactory<String, String> consumerFactory) {
this.consumerFactory = consumerFactory;
}
List<Message> getAllMessages() {
List<Message> messages = new ArrayList<>();
String clientId = Long.toString(Instant.now().getEpochSecond());
try (Consumer<String, String> consumer = consumerFactory.createConsumer(clientId, clientId)) {
consumer.subscribe(TOPICS_TO_SUBSCRIBE);
ConsumerRecords<String, String> consumerRecords = pollConsumerRecords(consumer);
consumerRecords.forEach(
consumerRecord ->
messages.add(new Message(consumerRecord.timestamp(), consumerRecord.value())));
log.debug(String.format("consumed %d messages", consumerRecords.count()));
}
return messages;
}
List<Message> getLastMessages(long offset) {
List<Message> messages = new ArrayList<>();
try (Consumer<String, String> consumer = createConsumer(offset)) {
ConsumerRecords<String, String> consumerRecords = pollConsumerRecords(consumer);
consumerRecords.forEach(consumerRecord ->
messages.add(new Message(consumerRecord.timestamp(), consumerRecord.value())));
} catch (NoSuchElementException e) {
log.warn("not able to create consumer and to poll messages");
return Collections.emptyList();
}
return messages;
}
private Consumer<String, String> createConsumer(long offsetFromLastIndex) {
String clientId = Long.toString(Instant.now().getEpochSecond());
Consumer<String, String> consumer = consumerFactory.createConsumer(clientId, clientId);
consumer.subscribe(TOPICS_TO_SUBSCRIBE);
seekConsumerTo(consumer, offsetFromLastIndex);
return consumer;
}
private void seekConsumerTo(Consumer<String, String> consumer, long offsetFromLastIndex) {
consumer.seekToEnd(consumer.assignment());
pollConsumerRecords(consumer);
TopicPartition topicPartition = consumer.assignment().iterator().next();
long topicCurrentSize = consumer.position(topicPartition);
long indexToSeek = offsetFromLastIndex > topicCurrentSize ? 0 : topicCurrentSize - offsetFromLastIndex;
consumer.seek(topicPartition, indexToSeek);
}
private ConsumerRecords<String, String> pollConsumerRecords(Consumer<String, String> consumer) {
return consumer.poll(Duration.ofMillis(CONSUMING_DURATION_IN_MS));
}
}
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