1 files changed, 121 insertions, 0 deletions
diff --git a/src/main/java/org/onap/dcae/common/publishing/DMaaPPublishersCache.java b/src/main/java/org/onap/dcae/common/publishing/DMaaPPublishersCache.java
new file mode 100644
index 00000000..b7997ef9
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+++ b/src/main/java/org/onap/dcae/common/publishing/DMaaPPublishersCache.java
@@ -0,0 +1,121 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2018 Nokia. 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.dcae.common.publishing;
+
+import com.att.nsa.cambria.client.CambriaBatchingPublisher;
+import com.google.common.cache.*;
+import io.vavr.collection.Map;
+import io.vavr.control.Option;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.annotation.Nonnull;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static io.vavr.API.Option;
+import static org.onap.dcae.common.publishing.VavrUtils.f;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+class DMaaPPublishersCache {
+
+    private static final Logger log = LoggerFactory.getLogger(DMaaPPublishersCache.class);
+    private final LoadingCache<String, CambriaBatchingPublisher> publishersCache;
+    private AtomicReference<Map<String, PublisherConfig>> dMaaPConfiguration;
+
+    DMaaPPublishersCache(Map<String, PublisherConfig> dMaaPConfiguration) {
+        this.dMaaPConfiguration = new AtomicReference<>(dMaaPConfiguration);
+        this.publishersCache = CacheBuilder.newBuilder()
+                .removalListener(new OnPublisherRemovalListener())
+                .build(new CambriaPublishersCacheLoader());
+    }
+
+    DMaaPPublishersCache(CambriaPublishersCacheLoader dMaaPPublishersCacheLoader,
+                         OnPublisherRemovalListener onPublisherRemovalListener,
+                         Map<String, PublisherConfig> dMaaPConfiguration) {
+        this.dMaaPConfiguration = new AtomicReference<>(dMaaPConfiguration);
+        this.publishersCache = CacheBuilder.newBuilder()
+                .removalListener(onPublisherRemovalListener)
+                .build(dMaaPPublishersCacheLoader);
+    }
+
+    Option<CambriaBatchingPublisher> getPublisher(String streamID) {
+        try {
+            return Option(publishersCache.getUnchecked(streamID));
+        } catch (Exception e) {
+            log.warn("Could not create / load Cambria Publisher for streamID", e);
+            return Option.none();
+        }
+    }
+
+    void closePublisherFor(String streamId) {
+        publishersCache.invalidate(streamId);
+    }
+
+    synchronized void reconfigure(Map<String, PublisherConfig> newConfig) {
+        Map<String, PublisherConfig> currentConfig = dMaaPConfiguration.get();
+        Map<String, PublisherConfig> removedConfigurations = currentConfig
+                .filterKeys(domain -> !newConfig.containsKey(domain));
+        Map<String, PublisherConfig> changedConfigurations = newConfig
+                .filterKeys(e -> currentConfig.containsKey(e) && !currentConfig.get(e).equals(newConfig.get(e)));
+        dMaaPConfiguration.set(newConfig);
+        removedConfigurations.merge(changedConfigurations).forEach(e -> publishersCache.invalidate(e._1));
+    }
+
+    static class OnPublisherRemovalListener implements RemovalListener<String, CambriaBatchingPublisher> {
+
+        @Override
+        public void onRemoval(@Nonnull RemovalNotification<String, CambriaBatchingPublisher> notification) {
+            CambriaBatchingPublisher publisher = notification.getValue();
+            if (publisher != null) { // The value might get Garbage Collected at this moment, regardless of @Nonnull
+                try {
+                    int timeout = 20;
+                    TimeUnit unit = TimeUnit.SECONDS;
+                    java.util.List<?> stuck = publisher.close(timeout, unit);
+                    if (!stuck.isEmpty()) {
+                        log.error(f("Publisher got stuck and did not manage to close in '%s' '%s', "
+                                + "%s messages were dropped", stuck.size(), timeout, unit));
+                    }
+                } catch (InterruptedException | IOException e) {
+                    log.error("Could not close Cambria publisher, some messages might have been dropped", e);
+                    Thread.currentThread().interrupt();
+                }
+            }
+        }
+    }
+
+    class CambriaPublishersCacheLoader extends CacheLoader<String, CambriaBatchingPublisher> {
+
+        @Override
+        public CambriaBatchingPublisher load(@Nonnull String domain) {
+            return dMaaPConfiguration.get()
+                    .get(domain)
+                    .toTry(() -> new RuntimeException(
+                            f("DMaaP configuration contains no configuration for domain: '%s'", domain)))
+                    .flatMap(DMaaPPublishersBuilder::buildPublisher)
+                    .get();
+        }
+    }
+
+}