2 * ============LICENSE_START=======================================================
4 * ================================================================================
5 * Copyright (C) 2023 Nordix Foundation. All rights reserved.
6 * ================================================================================
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * ============LICENSE_END=========================================================
21 package org.onap.dmaap.kafka;
23 import java.time.Duration;
24 import java.util.ArrayList;
25 import java.util.List;
26 import java.util.Properties;
27 import java.util.UUID;
28 import org.apache.kafka.clients.CommonClientConfigs;
29 import org.apache.kafka.clients.consumer.ConsumerConfig;
30 import org.apache.kafka.clients.consumer.ConsumerRecord;
31 import org.apache.kafka.clients.consumer.ConsumerRecords;
32 import org.apache.kafka.clients.consumer.KafkaConsumer;
33 import org.apache.kafka.common.KafkaException;
34 import org.apache.kafka.common.config.SaslConfigs;
35 import org.slf4j.Logger;
36 import org.slf4j.LoggerFactory;
39 * Utility class that provides a KafkaConsumer to communicate with a kafka cluster
41 public class OnapKafkaConsumer {
43 private final Logger log = LoggerFactory.getLogger(OnapKafkaConsumer.class);
44 private final KafkaConsumer<String, String> consumer;
45 private final int pollTimeout;
46 private final List<String> consumerTopics;
50 * @param configuration The config provided to the client
52 public OnapKafkaConsumer(IKafkaConfig configuration) {
53 consumerTopics = configuration.getConsumerTopics();
54 log.debug("Instantiating kafka consumer for topics {}", consumerTopics);
56 Properties props = new Properties();
57 props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
58 props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
59 props.put(ConsumerConfig.CLIENT_ID_CONFIG, configuration.getConsumerID() + "-consumer-" + UUID.randomUUID());
60 props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, configuration.getKafkaSecurityProtocolConfig());
61 props.put(CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG, configuration.getKafkaBootstrapServers());
62 props.put(SaslConfigs.SASL_JAAS_CONFIG, configuration.getKafkaSaslJaasConfig());
63 props.put(SaslConfigs.SASL_MECHANISM, configuration.getKafkaSaslMechanism());
64 props.put(ConsumerConfig.GROUP_ID_CONFIG, configuration.getConsumerGroup());
65 props.put(ConsumerConfig.ALLOW_AUTO_CREATE_TOPICS_CONFIG, false);
66 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "latest");
67 props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
69 consumer = new KafkaConsumer<>(props);
71 pollTimeout = configuration.getPollingTimeout();
75 * Poll specified topic for existing messages
77 * @return List of messages from a specific topic
79 List<String> poll(String topicName) throws KafkaException {
80 List<String> msgs = new ArrayList<>();
81 log.debug("Polling records for topic {}", topicName);
82 ConsumerRecords<String, String> consumerRecordsForSpecificTopic = consumer.poll(Duration.ofSeconds(pollTimeout));
83 for(ConsumerRecord<String, String> rec : consumerRecordsForSpecificTopic){
84 if (rec.topic().equals(topicName)) {
85 msgs.add(rec.value());
92 * Poll topics for existing messages
94 * @return List of messages from all subscribed topic
96 List<String> poll() throws KafkaException {
97 List<String> msgs = new ArrayList<>();
98 log.debug("Polling all records");
99 ConsumerRecords<String, String> consumerRecords = consumer.poll(Duration.ofSeconds(pollTimeout));
100 for(ConsumerRecord<String, String> rec : consumerRecords){
101 msgs.add(rec.value());
106 public void subscribeConsumerToTopics() {
108 consumer.subscribe(consumerTopics);
110 catch (KafkaException e) {
111 log.error("Failed to subscribe to given topic(s) {} : {}", consumerTopics, e.getMessage());