YARN-8549 Adding a NoOp timeline writer and reader plugin classes for ATSv2. Contributed by Prabha Manepalli.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/NoOpTimelineReaderImpl.java

@@ -0,0 +1,80 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hadoop.yarn.server.timelineservice.storage;
+
+import org.apache.hadoop.service.AbstractService;
+import org.apache.hadoop.yarn.api.records.timelineservice.TimelineEntity;
+import org.apache.hadoop.yarn.server.timelineservice.reader.TimelineDataToRetrieve;
+import org.apache.hadoop.yarn.server.timelineservice.reader.TimelineEntityFilters;
+import org.apache.hadoop.yarn.server.timelineservice.reader.TimelineReaderContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Stub based implementation for TimelineReader. This implementation will
+ * not provide a complete implementation of all the necessary features. This
+ * implementation is provided solely for basic testing purposes.
+ */
+
+public class NoOpTimelineReaderImpl extends AbstractService
+        implements TimelineReader {
+  private static final Logger LOG =
+          LoggerFactory.getLogger(NoOpTimelineReaderImpl.class);
+
+  public NoOpTimelineReaderImpl() {
+    super(NoOpTimelineReaderImpl.class.getName());
+    LOG.info("NoOpTimelineReader is configured. Response to all the read " +
+            "requests would be empty");
+  }
+
+  @Override
+  public TimelineEntity getEntity(TimelineReaderContext context,
+       TimelineDataToRetrieve dataToRetrieve) throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineReader is configured. Response to all the read " +
+              "requests would be empty");
+    }
+    return new TimelineEntity();
+  }
+
+  @Override
+  public Set<TimelineEntity> getEntities(TimelineReaderContext context,
+          TimelineEntityFilters filters, TimelineDataToRetrieve dataToRetrieve)
+          throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineReader is configured. Response to all the read " +
+              "requests would be empty");
+    }
+    return new HashSet<>();
+  }
+
+  @Override
+  public Set<String> getEntityTypes(TimelineReaderContext context)
+          throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineReader is configured. Response to all the read " +
+              "requests would be empty");
+    }
+    return new HashSet<>();
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/storage/NoOpTimelineWriterImpl.java

@@ -0,0 +1,88 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hadoop.yarn.server.timelineservice.storage;
+
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.service.AbstractService;
+import org.apache.hadoop.yarn.api.records.timelineservice.TimelineDomain;
+import org.apache.hadoop.yarn.api.records.timelineservice.TimelineEntities;
+import org.apache.hadoop.yarn.api.records.timelineservice.TimelineEntity;
+import org.apache.hadoop.yarn.api.records.timelineservice.TimelineWriteResponse;
+import org.apache.hadoop.yarn.server.timelineservice.collector.TimelineCollectorContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+/**
+ * Stub based implementation for TimelineWriter. This implementation will
+ * not provide a complete implementation of all the necessary features. This
+ * implementation is provided solely for basic testing purposes.
+ */
+
+public class NoOpTimelineWriterImpl extends AbstractService implements
+                                                      TimelineWriter{
+  private static final Logger LOG =
+          LoggerFactory.getLogger(NoOpTimelineWriterImpl.class);
+
+  public NoOpTimelineWriterImpl() {
+    super(NoOpTimelineWriterImpl.class.getName());
+    LOG.info("NoOpTimelineWriter is configured. All the writes to the backend" +
+            " are ignored");
+  }
+
+  @Override
+  public TimelineWriteResponse write(TimelineCollectorContext context,
+                                     TimelineEntities data,
+                                     UserGroupInformation callerUgi)
+                                     throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineWriter is configured. Not storing " +
+              "TimelineEntities.");
+    }
+    return new TimelineWriteResponse();
+  }
+
+  @Override
+  public TimelineWriteResponse write(TimelineCollectorContext context,
+                                     TimelineDomain domain) throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineWriter is configured. Not storing " +
+              "TimelineEntities.");
+    }
+    return new TimelineWriteResponse();
+  }
+
+  @Override
+  public TimelineWriteResponse aggregate(TimelineEntity data,
+                                         TimelineAggregationTrack track)
+                                         throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineWriter is configured. Not aggregating " +
+              "TimelineEntities.");
+    }
+    return new TimelineWriteResponse();
+  }
+
+  @Override
+  public void flush() throws IOException {
+    if(LOG.isDebugEnabled()){
+      LOG.debug("NoOpTimelineWriter is configured. Ignoring flush call");
+    }
+  }
+}