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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.restclient;
import java.util.EnumMap;
import java.util.Map;
import java.util.Properties;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.core.Response;
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.ApexEventRuntimeException;
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 from a REST server.
*
* @author Liam Fallon (liam.fallon@ericsson.com)
*/
public class ApexRestClientConsumer implements ApexEventConsumer, Runnable {
// Get a reference to the logger
private static final Logger LOGGER = LoggerFactory.getLogger(ApexRestClientConsumer.class);
// The amount of time to wait in milliseconds between checks that the consumer thread has stopped
private static final long REST_CLIENT_WAIT_SLEEP_TIME = 50;
// The REST parameters read from the parameter service
private RestClientCarrierTechnologyParameters restConsumerProperties;
// The event receiver that will receive events from this consumer
private ApexEventReceiver eventReceiver;
// The HTTP client that makes a REST call to get an input event for Apex
private Client client;
// 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;
@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 REST Properties
if (!(consumerParameters.getCarrierTechnologyParameters() instanceof RestClientCarrierTechnologyParameters)) {
final String errorMessage = "specified consumer properties are not applicable to REST client consumer ("
+ this.name + ")";
LOGGER.warn(errorMessage);
throw new ApexEventException(errorMessage);
}
restConsumerProperties = (RestClientCarrierTechnologyParameters) consumerParameters
.getCarrierTechnologyParameters();
// Check if the HTTP method has been set
if (restConsumerProperties.getHttpMethod() == null) {
restConsumerProperties.setHttpMethod(RestClientCarrierTechnologyParameters.HttpMethod.GET);
}
if (!RestClientCarrierTechnologyParameters.HttpMethod.GET.equals(restConsumerProperties.getHttpMethod())) {
final String errorMessage = "specified HTTP method of \"" + restConsumerProperties.getHttpMethod()
+ "\" is invalid, only HTTP method \"GET\" "
+ "is supported for event reception on REST client consumer (" + this.name + ")";
LOGGER.warn(errorMessage);
throw new ApexEventException(errorMessage);
}
// Initialize the HTTP client
client = ClientBuilder.newClient();
}
/**
* {@inheritDoc}.
*/
@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();
}
/**
* {@inheritDoc}.
*/
@Override
public String getName() {
return name;
}
/**
* {@inheritDoc}.
*/
@Override
public PeeredReference getPeeredReference(final EventHandlerPeeredMode peeredMode) {
return peerReferenceMap.get(peeredMode);
}
/**
* {@inheritDoc}.
*/
@Override
public void setPeeredReference(final EventHandlerPeeredMode peeredMode, final PeeredReference peeredReference) {
peerReferenceMap.put(peeredMode, peeredReference);
}
/**
* {@inheritDoc}.
*/
@Override
public void run() {
// The RequestRunner thread runs the get request for the event
Thread requestRunnerThread = null;
// The endless loop that receives events using REST calls
while (consumerThread.isAlive() && !stopOrderedFlag) {
// Create a new request if one is not in progress
if (requestRunnerThread == null || !requestRunnerThread.isAlive()) {
requestRunnerThread = new Thread(new RequestRunner());
requestRunnerThread.start();
}
ThreadUtilities.sleep(REST_CLIENT_WAIT_SLEEP_TIME);
}
client.close();
}
/**
* {@inheritDoc}.
*/
@Override
public void stop() {
stopOrderedFlag = true;
while (consumerThread.isAlive()) {
ThreadUtilities.sleep(REST_CLIENT_WAIT_SLEEP_TIME);
}
}
/**
* This class is used to start a thread for each request issued.
*
* @author Liam Fallon (liam.fallon@ericsson.com)
*/
private class RequestRunner implements Runnable {
/**
* {@inheritDoc}.
*/
@Override
public void run() {
try {
final Response response = client.target(restConsumerProperties.getUrl()).request("application/json")
.headers(restConsumerProperties.getHttpHeadersAsMultivaluedMap()).get();
// Check that the event request worked
if (!Response.Status.Family.familyOf(response.getStatus()).equals(Response.Status.Family.SUCCESSFUL)) {
final String errorMessage = "reception of event from URL \"" + restConsumerProperties.getUrl()
+ "\" failed with status code " + response.getStatus() + " and message \""
+ response.readEntity(String.class) + "\"";
throw new ApexEventRuntimeException(errorMessage);
}
// Get the event we received
final String eventJsonString = response.readEntity(String.class);
// Check there is content
if (eventJsonString == null || eventJsonString.trim().length() == 0) {
final String errorMessage = "received an empty event from URL \"" + restConsumerProperties.getUrl()
+ "\"";
throw new ApexEventRuntimeException(errorMessage);
}
// Send the event into Apex
eventReceiver.receiveEvent(new Properties(), eventJsonString);
} catch (final Exception e) {
LOGGER.warn("error receiving events on thread {}", consumerThread.getName(), e);
}
}
}
/**
* Hook for unit test mocking of HTTP client.
*
* @param client the mocked client
*/
protected void setClient(final Client client) {
this.client = client;
}
}
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