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    *
    * 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.
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  package org.apache.hadoop.hbase.coprocessor;
  
  import static org.junit.Assert.fail;
  
  import java.io.IOException;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.CoprocessorEnvironment;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.MiniHBaseCluster;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.Waiter.Predicate;
  import org.apache.hadoop.hbase.client.Durability;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.regionserver.HRegionServer;
  import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.junit.Assert;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  /**
   * Tests unhandled exceptions thrown by coprocessors running on a regionserver..
   * Expected result is that the regionserver will abort with an informative
   * error message describing the set of its loaded coprocessors for crash
   * diagnosis. (HBASE-4014).
   */
  @Category(MediumTests.class)
  public class TestRegionServerCoprocessorExceptionWithAbort {
  
    private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private static final TableName TABLE_NAME = TableName.valueOf("observed_table");
  
    @Test(timeout=60000)
    public void testExceptionDuringInitialization() throws Exception {
      Configuration conf = TEST_UTIL.getConfiguration();
      conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 2);  // Let's fail fast.
      conf.setBoolean(CoprocessorHost.ABORT_ON_ERROR_KEY, true);
      conf.set(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY, "");
      TEST_UTIL.startMiniCluster(2);
      try {
        MiniHBaseCluster cluster = TEST_UTIL.getHBaseCluster();
        // Trigger one regionserver to fail as if it came up with a coprocessor
        // that fails during initialization
        final HRegionServer regionServer = cluster.getRegionServer(0);
        conf.set(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY,
          FailedInitializationObserver.class.getName());
        regionServer.getRegionServerCoprocessorHost().loadSystemCoprocessors(conf,
          CoprocessorHost.REGION_COPROCESSOR_CONF_KEY);
        TEST_UTIL.waitFor(10000, 1000, new Predicate<Exception>() {
          @Override
          public boolean evaluate() throws Exception {
            return regionServer.isAborted();
          }
        });
      } finally {
        TEST_UTIL.shutdownMiniCluster();
      }
    }
  
    @Test(timeout=60000)
    public void testExceptionFromCoprocessorDuringPut() throws Exception {
      // set configure to indicate which cp should be loaded
      Configuration conf = TEST_UTIL.getConfiguration();
      conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 2);  // Let's fail fast.
      conf.set(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY, BuggyRegionObserver.class.getName());
      conf.setBoolean(CoprocessorHost.ABORT_ON_ERROR_KEY, true);
      TEST_UTIL.startMiniCluster(2);
      try {
        // When we try to write to TEST_TABLE, the buggy coprocessor will
        // cause a NullPointerException, which will cause the regionserver (which
        // hosts the region we attempted to write to) to abort.
        final byte[] TEST_FAMILY = Bytes.toBytes("aaa");
  
        HTable table = TEST_UTIL.createMultiRegionTable(TABLE_NAME, TEST_FAMILY);
        TEST_UTIL.waitUntilAllRegionsAssigned(TABLE_NAME);
  
       // Note which regionServer will abort (after put is attempted).
       final HRegionServer regionServer = TEST_UTIL.getRSForFirstRegionInTable(TABLE_NAME);
 
       try {
         final byte[] ROW = Bytes.toBytes("aaa");
         Put put = new Put(ROW);
         put.add(TEST_FAMILY, ROW, ROW);
         table.put(put);
         table.flushCommits();
       } catch (IOException e) {
         // The region server is going to be aborted.
         // We may get an exception if we retry,
         // which is not guaranteed.
       }
 
       // Wait 10 seconds for the regionserver to abort: expected result is that
       // it will abort.
       boolean aborted = false;
       for (int i = 0; i < 10; i++) {
         aborted = regionServer.isAborted(); 
         if (aborted) {
           break;
         }
         try {
           Thread.sleep(1000);
         } catch (InterruptedException e) {
           fail("InterruptedException while waiting for regionserver " +
             "zk node to be deleted.");
         }
       }
       Assert.assertTrue("The region server should have aborted", aborted);
       table.close();
     } finally {
       TEST_UTIL.shutdownMiniCluster();
     }
   }
 
   public static class FailedInitializationObserver extends SimpleRegionObserver {
     @Override
     @SuppressWarnings("null")
     @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NP_NULL_ON_SOME_PATH",
       justification="Preconditions checks insure we are not going to dereference a null value")
     public void start(CoprocessorEnvironment e) throws IOException {
       // Trigger a NPE to fail the coprocessor
       Integer i = null;
       i = i + 1;
     }
   }
 
   public static class BuggyRegionObserver extends SimpleRegionObserver {
     @Override
     @SuppressWarnings("null")
     @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NP_NULL_ON_SOME_PATH",
       justification="Preconditions checks insure we are not going to dereference a null value")
     public void prePut(final ObserverContext<RegionCoprocessorEnvironment> c,
                        final Put put, final WALEdit edit,
                        final Durability durability) {
       String tableName =
           c.getEnvironment().getRegion().getRegionInfo().getTable().getNameAsString();
       if (tableName.equals("observed_table")) {
         // Trigger a NPE to fail the coprocessor
         Integer i = null;
         i = i + 1;
       }
     }
   }
 }