/**
    * 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.hbase.client;
  
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.commons.logging.impl.Log4JLogger;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.MiniHBaseCluster.MiniHBaseClusterRegionServer;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.CoordinatedStateManager;
  import org.apache.hadoop.hbase.ipc.AbstractRpcClient;
  import org.apache.hadoop.hbase.ipc.RpcServer;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ScanRequest;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ScanResponse;
  import org.apache.hadoop.hbase.regionserver.HRegionServer;
  import org.apache.hadoop.hbase.regionserver.RSRpcServices;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.log4j.Level;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  import com.google.protobuf.RpcController;
  import com.google.protobuf.ServiceException;
  
  /**
   * Test the scenario where a HRegionServer#scan() call, while scanning, timeout at client side and
   * getting retried. This scenario should not result in some data being skipped at RS side.
   */
  @Category(MediumTests.class)
  public class TestClientScannerRPCTimeout {
    private static final Log LOG = LogFactory.getLog(TestClientScannerRPCTimeout.class);
    private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private static final byte[] FAMILY = Bytes.toBytes("testFamily");
    private static final byte[] QUALIFIER = Bytes.toBytes("testQualifier");
    private static final byte[] VALUE = Bytes.toBytes("testValue");
    private static final int rpcTimeout = 2 * 1000;
    private static final int CLIENT_RETRIES_NUMBER = 3;
  
    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
      ((Log4JLogger)RpcServer.LOG).getLogger().setLevel(Level.ALL);
      ((Log4JLogger)AbstractRpcClient.LOG).getLogger().setLevel(Level.ALL);
      ((Log4JLogger)ScannerCallable.LOG).getLogger().setLevel(Level.ALL);
      Configuration conf = TEST_UTIL.getConfiguration();
      // Don't report so often so easier to see other rpcs
      conf.setInt("hbase.regionserver.msginterval", 3 * 10000);
      conf.setInt(HConstants.HBASE_RPC_TIMEOUT_KEY, rpcTimeout);
      conf.setStrings(HConstants.REGION_SERVER_IMPL, RegionServerWithScanTimeout.class.getName());
      conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, CLIENT_RETRIES_NUMBER);
      conf.setInt(HConstants.HBASE_CLIENT_PAUSE, 1000);
      TEST_UTIL.startMiniCluster(1);
    }
  
    @AfterClass
    public static void tearDownAfterClass() throws Exception {
      TEST_UTIL.shutdownMiniCluster();
    }
  
    @Test
    public void testScannerNextRPCTimesout() throws Exception {
      final TableName TABLE_NAME = TableName.valueOf("testScannerNextRPCTimesout");
      Table ht = TEST_UTIL.createTable(TABLE_NAME, FAMILY);
      byte[] r0 = Bytes.toBytes("row-0");
      byte[] r1 = Bytes.toBytes("row-1");
      byte[] r2 = Bytes.toBytes("row-2");
      byte[] r3 = Bytes.toBytes("row-3");
      putToTable(ht, r0);
      putToTable(ht, r1);
      putToTable(ht, r2);
      putToTable(ht, r3);
      LOG.info("Wrote our three values");
      RSRpcServicesWithScanTimeout.seqNoToSleepOn = 1;
      Scan scan = new Scan();
      scan.setCaching(1);
     ResultScanner scanner = ht.getScanner(scan);
     Result result = scanner.next();
     // fetched when openScanner
     assertTrue("Expected row: row-0", Bytes.equals(r0, result.getRow()));
     result = scanner.next();
     assertTrue("Expected row: row-1", Bytes.equals(r1, result.getRow()));
     LOG.info("Got expected first row");
     long t1 = System.currentTimeMillis();
     result = scanner.next();
     assertTrue((System.currentTimeMillis() - t1) > rpcTimeout);
     assertTrue("Expected row: row-2", Bytes.equals(r2, result.getRow()));
     RSRpcServicesWithScanTimeout.seqNoToSleepOn = -1;// No need of sleep
     result = scanner.next();
     assertTrue("Expected row: row-3", Bytes.equals(r3, result.getRow()));
     scanner.close();
 
     // test the case that RPC is always timesout
     scanner = ht.getScanner(scan);
     RSRpcServicesWithScanTimeout.sleepAlways = true;
     RSRpcServicesWithScanTimeout.tryNumber = 0;
     try {
       result = scanner.next();
     } catch (IOException ioe) {
       // catch the exception after max retry number
       LOG.info("Failed after maximal attempts=" + CLIENT_RETRIES_NUMBER, ioe);
     }
     assertTrue("Expected maximal try number=" + CLIENT_RETRIES_NUMBER
         + ", actual =" + RSRpcServicesWithScanTimeout.tryNumber,
         RSRpcServicesWithScanTimeout.tryNumber <= CLIENT_RETRIES_NUMBER);
   }
 
   private void putToTable(Table ht, byte[] rowkey) throws IOException {
     Put put = new Put(rowkey);
     put.add(FAMILY, QUALIFIER, VALUE);
     ht.put(put);
   }
 
   private static class RegionServerWithScanTimeout extends MiniHBaseClusterRegionServer {
     public RegionServerWithScanTimeout(Configuration conf, CoordinatedStateManager cp)
         throws IOException, InterruptedException {
       super(conf, cp);
     }
 
     protected RSRpcServices createRpcServices() throws IOException {
       return new RSRpcServicesWithScanTimeout(this);
     }
   }
 
   private static class RSRpcServicesWithScanTimeout extends RSRpcServices {
     private long tableScannerId;
     private boolean slept;
     private static long seqNoToSleepOn = -1;
     private static boolean sleepAlways = false;
     private static int tryNumber = 0;
 
     public RSRpcServicesWithScanTimeout(HRegionServer rs)
         throws IOException {
       super(rs);
     }
 
     @Override
     public ScanResponse scan(final RpcController controller, final ScanRequest request)
         throws ServiceException {
       if (request.hasScannerId()) {
         ScanResponse scanResponse = super.scan(controller, request);
         if (this.tableScannerId == request.getScannerId() && 
             (sleepAlways || (!slept && seqNoToSleepOn == request.getNextCallSeq()))) {
           try {
             LOG.info("SLEEPING " + (rpcTimeout + 500));
             Thread.sleep(rpcTimeout + 500);
           } catch (InterruptedException e) {
           }
           slept = true;
           tryNumber++;
           if (tryNumber > 2 * CLIENT_RETRIES_NUMBER) {
             sleepAlways = false;
           }
         }
         return scanResponse;
       } else {
         ScanResponse scanRes = super.scan(controller, request);
         String regionName = Bytes.toString(request.getRegion().getValue().toByteArray());
         if (!regionName.contains(TableName.META_TABLE_NAME.getNameAsString())) {
           tableScannerId = scanRes.getScannerId();
         }
         return scanRes;
       }
     }
   }
 }