Add CDS client

Change-Id: I3f77a2c9e8341239b97675f5897cecf28c7dfb6f
Issue-ID: SO-1483
Signed-off-by: Alexis de Talhouët <adetalhouet89@gmail.com>

4 files changed, 244 insertions, 0 deletions

diff --git a/common/src/main/java/org/onap/so/client/cds/CDSProcessingClient.java b/common/src/main/java/org/onap/so/client/cds/CDSProcessingClient.java
new file mode 100644
index 0000000000..0901cf589b
--- /dev/null
+++ b/common/src/main/java/org/onap/so/client/cds/CDSProcessingClient.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2019 Bell Canada.
+ *
+ * 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.
+ */
+package org.onap.so.client.cds;
+
+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.apps.controllerblueprints.processing.api.ExecutionServiceInput;
+import org.onap.so.client.PreconditionFailedException;
+import org.onap.so.client.RestPropertiesLoader;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * <p>
+ * The CDS processing client is using gRPC for communication between SO and CDS.
+ * That communication is configured to use a streaming approach, meaning that
+ * client can send an event to which server can reply will multiple sub-responses,
+ * until full completion of the processing.
+ * </p>
+ * <p>
+ * In order for the caller to manage the callback, it is the responsibility of the
+ * caller to implement and provide a {@link CDSProcessingListener} so received messages
+ * can be handled appropriately.
+ * </p>
+ *
+ * Here is an example of implementation of such listener:
+ * <pre>
+ * new CDSProcessingListener {
+ *
+ *     &#64;Override
+ *     public void onMessage(ExecutionServiceOutput message) {
+ *         log.info("Received notification from CDS: {}", message);
+ *     }
+ *
+ *     &#64;Override
+ *     public void onError(Throwable t) {
+ *         Status status = Status.fromThrowable(t);
+ *         log.error("Failed processing blueprint {}", status, t);
+ *     }
+ * }
+ * </pre>
+ */
+public class CDSProcessingClient implements AutoCloseable {
+
+    private static final Logger log = LoggerFactory.getLogger(CDSProcessingClient.class);
+
+    private ManagedChannel channel;
+    private CDSProcessingHandler handler;
+
+    public CDSProcessingClient(final CDSProcessingListener listener) {
+        CDSProperties props = RestPropertiesLoader.getInstance().getNewImpl(CDSProperties.class);
+        if (props == null) {
+            throw new PreconditionFailedException(
+                "No RestProperty.CDSProperties implementation found on classpath, can't create client.");
+        }
+        this.channel = NettyChannelBuilder
+            .forAddress(props.getHost(), props.getPort())
+            .nameResolverFactory(new DnsNameResolverProvider())
+            .loadBalancerFactory(new PickFirstLoadBalancerProvider())
+            .usePlaintext()
+            .build();
+        this.handler = new CDSProcessingHandler(listener);
+        log.info("CDSProcessingClient started");
+    }
+
+    CDSProcessingClient(final ManagedChannel channel, final CDSProcessingHandler handler) {
+        this.channel = channel;
+        this.handler = handler;
+    }
+
+    /**
+     * Sends a request to the CDS backend micro-service.
+     *
+     * 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.
+     *
+     * It is the user responsibility to close the client.
+     *
+     * @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();
+        }
+        log.info("CDSProcessingClient stopped");
+    }
+}
\ No newline at end of file
diff --git a/common/src/main/java/org/onap/so/client/cds/CDSProcessingHandler.java b/common/src/main/java/org/onap/so/client/cds/CDSProcessingHandler.java
new file mode 100644
index 0000000000..244b89a6f5
--- /dev/null
+++ b/common/src/main/java/org/onap/so/client/cds/CDSProcessingHandler.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2019 Bell Canada.
+ *
+ * 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.
+ */
+package org.onap.so.client.cds;
+
+import io.grpc.ManagedChannel;
+import io.grpc.stub.StreamObserver;
+import java.util.concurrent.CountDownLatch;
+import org.onap.ccsdk.apps.controllerblueprints.common.api.ActionIdentifiers;
+import org.onap.ccsdk.apps.controllerblueprints.processing.api.BluePrintProcessingServiceGrpc;
+import org.onap.ccsdk.apps.controllerblueprints.processing.api.BluePrintProcessingServiceGrpc.BluePrintProcessingServiceStub;
+import org.onap.ccsdk.apps.controllerblueprints.processing.api.ExecutionServiceInput;
+import org.onap.ccsdk.apps.controllerblueprints.processing.api.ExecutionServiceOutput;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class CDSProcessingHandler {
+
+    private static final Logger log = LoggerFactory.getLogger(CDSProcessingHandler.class);
+
+    private CDSProcessingListener listener;
+
+    CDSProcessingHandler(final CDSProcessingListener listener) {
+        this.listener = listener;
+    }
+
+    CountDownLatch process(ExecutionServiceInput request, ManagedChannel channel) {
+
+        ActionIdentifiers header = request.getActionIdentifiers();
+
+        log.info("Processing blueprint({}:{}) for action({})", header.getBlueprintVersion(), header.getBlueprintName(),
+            header.getBlueprintVersion());
+
+        final CountDownLatch finishLatch = new CountDownLatch(1);
+
+        final BluePrintProcessingServiceStub asyncStub = BluePrintProcessingServiceGrpc.newStub(channel);
+
+        final StreamObserver<ExecutionServiceOutput> responseObserver = new StreamObserver<ExecutionServiceOutput>() {
+            @Override
+            public void onNext(ExecutionServiceOutput output) {
+                listener.onMessage(output);
+            }
+
+            @Override
+            public void onError(Throwable t) {
+                listener.onError(t);
+                finishLatch.countDown();
+            }
+
+            @Override
+            public void onCompleted() {
+                log.info("Completed blueprint({}:{}) for action({})", header.getBlueprintVersion(),
+                    header.getBlueprintName(), header.getBlueprintVersion());
+                finishLatch.countDown();
+            }
+        };
+
+        final StreamObserver<ExecutionServiceInput> requestObserver = asyncStub.process(responseObserver);
+
+        try {
+            // Send our message to CDS backend for processing
+            requestObserver.onNext(request);
+            // Mark the end of requests
+            requestObserver.onCompleted();
+        } catch (RuntimeException e) {
+            requestObserver.onError(e);
+        }
+        return finishLatch;
+    }
+}
\ No newline at end of file
diff --git a/common/src/main/java/org/onap/so/client/cds/CDSProcessingListener.java b/common/src/main/java/org/onap/so/client/cds/CDSProcessingListener.java
new file mode 100644
index 0000000000..2eae4ef5a7
--- /dev/null
+++ b/common/src/main/java/org/onap/so/client/cds/CDSProcessingListener.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 Bell Canada.
+ *
+ * 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.
+ */
+package org.onap.so.client.cds;
+
+import org.onap.ccsdk.apps.controllerblueprints.processing.api.ExecutionServiceOutput;
+
+public interface CDSProcessingListener {
+
+    void onMessage(ExecutionServiceOutput message);
+
+    void onError(Throwable t);
+}
diff --git a/common/src/main/java/org/onap/so/client/cds/CDSProperties.java b/common/src/main/java/org/onap/so/client/cds/CDSProperties.java
new file mode 100644
index 0000000000..bb2a54ec98
--- /dev/null
+++ b/common/src/main/java/org/onap/so/client/cds/CDSProperties.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 Bell Canada.
+ *
+ * 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.
+ */
+package org.onap.so.client.cds;
+
+import org.onap.so.client.RestProperties;
+
+
+public interface CDSProperties extends RestProperties {
+
+    String getHost();
+    int getPort();
+}