contrib/src/main/java/org/apache/apex/malhar/contrib/splunk/AbstractSplunkInputOperator.java

/**
 * 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.apex.malhar.contrib.splunk;

import java.io.InputStream;

import javax.validation.constraints.NotNull;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.apex.malhar.lib.db.AbstractStoreInputOperator;

import com.splunk.Event;
import com.splunk.JobExportArgs;
import com.splunk.MultiResultsReaderXml;
import com.splunk.SearchResults;

import com.datatorrent.api.Context.OperatorContext;

/**
 * This is the base implementation of a Splunk input adapter. 
 * Subclasses must implement the methods which convert Splunk event to tuples.
 * <p>
 * This is an abstract class. Sub-classes need to implement {@link #queryToRetrieveData()} and {@link #getTuple(String)}.
 * </p>
 * @displayName Abstract Splunk Input
 * @category Input
 * @tags splunk
 *
 * @since 1.0.4
 */
public abstract class AbstractSplunkInputOperator<T> extends AbstractStoreInputOperator<T, SplunkStore>
{
  private static final Logger logger = LoggerFactory.getLogger(AbstractSplunkInputOperator.class);
  @NotNull
  protected String earliestTime;
  protected String latestTime;
  protected transient JobExportArgs exportArgs;
  protected transient InputStream exportSearch;
  protected transient MultiResultsReaderXml multiResultsReader;

  public void setEarliestTime(@NotNull String earliestTime)
  {
    this.earliestTime = earliestTime;
  }

  public void setLatestTime(@NotNull String latestTime)
  {
    this.latestTime = latestTime;
  }

  /**
   * Any concrete class has to override this method to convert a Value of an Event into Tuple.
   *
   * @param value a single value that has been read from a splunk event.
   * @return Tuple a tuples created from row which can be any Java object.
   */
  public abstract T getTuple(String value);

  /**
   * Any concrete class has to override this method to return the query string which will be used to
   * retrieve data from splunk.
   *
   * @return Query string
   */
  public abstract String queryToRetrieveData();

  @Override
  public void setup(OperatorContext t1)
  {
    super.setup(t1);
    exportArgs = new JobExportArgs();
    exportArgs.setEarliestTime(earliestTime);
    exportArgs.setLatestTime(latestTime);
    exportArgs.setSearchMode(JobExportArgs.SearchMode.NORMAL);
  }

  /**
   * This executes the search query to retrieve result from splunk.
   * It then converts each event's value into tuple and emit that into output port.
   */
  @Override
  public void emitTuples()
  {
    String query = queryToRetrieveData();
    logger.debug(String.format("select statement: %s", query));

    try {
      exportSearch = store.getService().export(queryToRetrieveData(), exportArgs);
      multiResultsReader = new MultiResultsReaderXml(exportSearch);
      for (SearchResults searchResults : multiResultsReader) {
        for (Event event : searchResults) {
          for (String key: event.keySet()) {
            if (key.contains("raw")) {
              T tuple = getTuple(event.get(key));
              outputPort.emit(tuple);
            }
          }
        }
      }
      multiResultsReader.close();
    } catch (Exception e) {
      store.disconnect();
      throw new RuntimeException(String.format("Error while running query: %s", query), e);
    }
  }
}