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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2019 Bell Canada.
* Modifications Copyright (C) 2020 AT&T Intellectual Property. 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.policy.cds.client;
import com.google.common.base.Preconditions;
import io.grpc.ManagedChannel;
import io.grpc.internal.DnsNameResolverProvider;
import io.grpc.internal.PickFirstLoadBalancerProvider;
import io.grpc.netty.NettyChannelBuilder;
import java.util.concurrent.CountDownLatch;
import org.onap.ccsdk.cds.controllerblueprints.processing.api.ExecutionServiceInput;
import org.onap.policy.cds.api.CdsProcessorListener;
import org.onap.policy.cds.properties.CdsServerProperties;
import org.onap.policy.common.parameters.GroupValidationResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <p>
* The CDS processor client uses gRPC for communication between Policy and CDS. This communication is configured to use
* a streaming approach, which means the client sends an event to which the server can reply with multiple
* sub-responses, until full completion of the processing.
* </p>
*/
public class CdsProcessorGrpcClient implements AutoCloseable {
private static final Logger LOGGER = LoggerFactory.getLogger(CdsProcessorGrpcClient.class);
private ManagedChannel channel;
private CdsProcessorHandler handler;
/**
* Constructor, create a CDS processor gRPC client.
*
* @param listener the listener to listen on
*/
public CdsProcessorGrpcClient(final CdsProcessorListener listener, CdsServerProperties props) {
final GroupValidationResult validationResult = props.validate();
Preconditions.checkState(validationResult.getStatus().isValid(), "Error validating CDS server "
+ "properties: " + validationResult.getResult());
StringBuilder bldr = new StringBuilder("gRPC://");
bldr.append(props.getHost());
bldr.append(":");
bldr.append(props.getPort());
bldr.append('/');
String url = bldr.toString();
this.channel = NettyChannelBuilder.forAddress(props.getHost(), props.getPort())
.nameResolverFactory(new DnsNameResolverProvider())
.loadBalancerFactory(new PickFirstLoadBalancerProvider())
.intercept(new BasicAuthClientHeaderInterceptor(props)).usePlaintext().build();
this.handler = new CdsProcessorHandler(listener, url);
LOGGER.info("CdsProcessorListener started");
}
CdsProcessorGrpcClient(final ManagedChannel channel, final CdsProcessorHandler handler) {
this.channel = channel;
this.handler = handler;
}
/**
* Sends a request to the CDS backend micro-service.
*
* <p>The caller will be returned a CountDownLatch that can be used to define how long the processing can wait. The
* CountDownLatch is initiated with just 1 count. When the client receives an #onCompleted callback, the counter
* will decrement.</p>
*
* <p>It is the user responsibility to close the client.</p>
*
* @param input request to send
* @return CountDownLatch instance that can be use to #await for completeness of processing
*/
public CountDownLatch sendRequest(ExecutionServiceInput input) {
return handler.process(input, channel);
}
@Override
public void close() {
if (channel != null) {
channel.shutdown();
}
LOGGER.info("CdsProcessorListener stopped");
}
}
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