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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2016-2018 Ericsson. 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.
*
* SPDX-License-Identifier: Apache-2.0
* ============LICENSE_END=========================================================
*/
package org.onap.policy.apex.plugins.event.carrier.kafka;
import java.util.EnumMap;
import java.util.Map;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.onap.policy.apex.core.infrastructure.threading.ApplicationThreadFactory;
import org.onap.policy.apex.core.infrastructure.threading.ThreadUtilities;
import org.onap.policy.apex.service.engine.event.ApexEventConsumer;
import org.onap.policy.apex.service.engine.event.ApexEventException;
import org.onap.policy.apex.service.engine.event.ApexEventReceiver;
import org.onap.policy.apex.service.engine.event.PeeredReference;
import org.onap.policy.apex.service.parameters.eventhandler.EventHandlerParameters;
import org.onap.policy.apex.service.parameters.eventhandler.EventHandlerPeeredMode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This class implements an Apex event consumer that receives events using Kafka.
*
* @author Liam Fallon (liam.fallon@ericsson.com)
*/
public class ApexKafkaConsumer implements ApexEventConsumer, Runnable {
// Get a reference to the logger
private static final Logger LOGGER = LoggerFactory.getLogger(ApexKafkaConsumer.class);
// The Kafka parameters read from the parameter service
private KafkaCarrierTechnologyParameters kafkaConsumerProperties;
// The event receiver that will receive events from this consumer
private ApexEventReceiver eventReceiver;
// The Kafka consumer used to receive events using Kafka
private KafkaConsumer<String, String> kafkaConsumer;
// The name for this consumer
private String name = null;
// The peer references for this event handler
private Map<EventHandlerPeeredMode, PeeredReference> peerReferenceMap = new EnumMap<>(EventHandlerPeeredMode.class);
// The consumer thread and stopping flag
private Thread consumerThread;
private boolean stopOrderedFlag = false;
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.service.engine.event.ApexEventConsumer#init(java.lang.String,
* org.onap.policy.apex.service.parameters.eventhandler.EventHandlerParameters,
* org.onap.policy.apex.service.engine.event.ApexEventReceiver)
*/
@Override
public void init(final String consumerName, final EventHandlerParameters consumerParameters,
final ApexEventReceiver incomingEventReceiver) throws ApexEventException {
this.eventReceiver = incomingEventReceiver;
this.name = consumerName;
// Check and get the Kafka Properties
if (!(consumerParameters.getCarrierTechnologyParameters() instanceof KafkaCarrierTechnologyParameters)) {
LOGGER.warn("specified consumer properties of type \""
+ consumerParameters.getCarrierTechnologyParameters().getClass().getCanonicalName()
+ "\" are not applicable to a Kafka consumer");
throw new ApexEventException("specified consumer properties of type \""
+ consumerParameters.getCarrierTechnologyParameters().getClass().getCanonicalName()
+ "\" are not applicable to a Kafka consumer");
}
kafkaConsumerProperties =
(KafkaCarrierTechnologyParameters) consumerParameters.getCarrierTechnologyParameters();
// Kick off the Kafka consumer
kafkaConsumer = new KafkaConsumer<>(kafkaConsumerProperties.getKafkaConsumerProperties());
kafkaConsumer.subscribe(kafkaConsumerProperties.getConsumerTopicList());
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("event receiver for " + this.getClass().getName() + ":" + this.name + " subscribed to topics: "
+ kafkaConsumerProperties.getConsumerTopicList());
}
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.service.engine.event.ApexEventConsumer#start()
*/
@Override
public void start() {
// Configure and start the event reception thread
final String threadName = this.getClass().getName() + ":" + this.name;
consumerThread = new ApplicationThreadFactory(threadName).newThread(this);
consumerThread.setDaemon(true);
consumerThread.start();
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.service.engine.event.ApexEventConsumer#getName()
*/
@Override
public String getName() {
return name;
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.service.engine.event.ApexEventConsumer#getPeeredReference(org.onap.policy.apex.service.
* parameters.eventhandler.EventHandlerPeeredMode)
*/
@Override
public PeeredReference getPeeredReference(final EventHandlerPeeredMode peeredMode) {
return peerReferenceMap.get(peeredMode);
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.service.engine.event.ApexEventConsumer#setPeeredReference(org.onap.policy.apex.service.
* parameters.eventhandler.EventHandlerPeeredMode, org.onap.policy.apex.service.engine.event.PeeredReference)
*/
@Override
public void setPeeredReference(final EventHandlerPeeredMode peeredMode, final PeeredReference peeredReference) {
peerReferenceMap.put(peeredMode, peeredReference);
}
/*
* (non-Javadoc)
*
* @see java.lang.Runnable#run()
*/
@Override
public void run() {
// Kick off the Kafka consumer
kafkaConsumer = new KafkaConsumer<>(kafkaConsumerProperties.getKafkaConsumerProperties());
kafkaConsumer.subscribe(kafkaConsumerProperties.getConsumerTopicList());
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("event receiver for " + this.getClass().getName() + ":" + this.name + " subscribed to topics: "
+ kafkaConsumerProperties.getConsumerTopicList());
}
// The endless loop that receives events over Kafka
while (consumerThread.isAlive() && !stopOrderedFlag) {
try {
final ConsumerRecords<String, String> records =
kafkaConsumer.poll(kafkaConsumerProperties.getConsumerPollDuration().toMillis());
for (final ConsumerRecord<String, String> record : records) {
traceIfTraceEnabled(record);
eventReceiver.receiveEvent(record.value());
}
} catch (final Exception e) {
LOGGER.warn("error receiving events on thread {}", consumerThread.getName(), e);
}
}
if (!consumerThread.isInterrupted()) {
kafkaConsumer.close();
}
}
/**
* Trace a record if trace is enabled.
*
* @param record the record to trace
*/
private void traceIfTraceEnabled(final ConsumerRecord<String, String> record) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("event received for {} for forwarding to Apex engine : {} {}",
this.getClass().getName() + ":" + this.name, record.key(), record.value());
}
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.service.engine.event.ApexEventConsumer#stop()
*/
@Override
public void stop() {
stopOrderedFlag = true;
while (consumerThread.isAlive()) {
ThreadUtilities.sleep(kafkaConsumerProperties.getConsumerPollTime());
}
}
}
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