HBASE-8684: Table Coprocessor can't access external HTable by default

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1490043 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java

@@ -36,6 +36,7 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.Coprocessor;
 import org.apache.hadoop.hbase.CoprocessorEnvironment;
+import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
@@ -182,7 +183,9 @@ public class RegionCoprocessorHost
             }
             if (cfgSpec != null) {
               cfgSpec = cfgSpec.substring(cfgSpec.indexOf('|') + 1);
-              Configuration newConf = new Configuration(conf);
+              // do an explicit deep copy of the passed configuration
+              Configuration newConf = new Configuration(false);
+              HBaseConfiguration.merge(newConf, conf);
               Matcher m = HConstants.CP_HTD_ATTR_VALUE_PARAM_PATTERN.matcher(cfgSpec);
               while (m.find()) {
                 newConf.set(m.group(1), m.group(2));

hbase-server/src/test/java/org/apache/hadoop/hbase/TestOpenTableInCoprocessor.java

@@ -0,0 +1,131 @@
+/**
+ *
+ * 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;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+
+import org.apache.hadoop.hbase.client.Durability;
+import org.apache.hadoop.hbase.client.HBaseAdmin;
+import org.apache.hadoop.hbase.client.HTable;
+import org.apache.hadoop.hbase.client.HTableInterface;
+import org.apache.hadoop.hbase.client.Put;
+import org.apache.hadoop.hbase.client.Result;
+import org.apache.hadoop.hbase.client.ResultScanner;
+import org.apache.hadoop.hbase.client.Scan;
+import org.apache.hadoop.hbase.coprocessor.BaseRegionObserver;
+import org.apache.hadoop.hbase.coprocessor.ObserverContext;
+import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
+import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.junit.AfterClass;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+/**
+ * Test that a coprocessor can open a connection and write to another table, inside a hook.
+ */
+@Category(MediumTests.class)
+public class TestOpenTableInCoprocessor {
+
+  private static final byte[] otherTable = Bytes.toBytes("otherTable");
+  private static final byte[] family = new byte[] { 'f' };
+
+  private static boolean completed = false;
+
+  /**
+   * Custom coprocessor that just copies the write to another table.
+   */
+  public static class SendToOtherTableCoprocessor extends BaseRegionObserver {
+
+    @Override
+    public void prePut(ObserverContext<RegionCoprocessorEnvironment> e, Put put, WALEdit edit,
+        final Durability durability) throws IOException {
+      HTableInterface table = e.getEnvironment().getTable(otherTable);
+      Put p = new Put(new byte[] { 'a' });
+      p.add(family, null, new byte[] { 'a' });
+      table.put(put);
+      table.flushCommits();
+      completed = true;
+      table.close();
+    }
+
+  }
+
+  private static final HBaseTestingUtility UTIL = new HBaseTestingUtility();
+
+  @AfterClass
+  public static void cleanup() throws Exception {
+    UTIL.getHBaseAdmin().close();
+  }
+
+  @Test
+  public void testCoprocessorCanCreateConnectionToRemoteTable() throws Throwable {
+    HTableDescriptor primary = new HTableDescriptor("primary");
+    primary.addFamily(new HColumnDescriptor(family));
+    // add our coprocessor
+    primary.addCoprocessor(SendToOtherTableCoprocessor.class.getName());
+
+    HTableDescriptor other = new HTableDescriptor(otherTable);
+    other.addFamily(new HColumnDescriptor(family));
+    UTIL.startMiniCluster();
+
+    HBaseAdmin admin = UTIL.getHBaseAdmin();
+    admin.createTable(primary);
+    admin.createTable(other);
+    admin.close();
+
+    HTable table = new HTable(UTIL.getConfiguration(), "primary");
+    Put p = new Put(new byte[] { 'a' });
+    p.add(family, null, new byte[] { 'a' });
+    table.put(p);
+    table.flushCommits();
+    table.close();
+
+    HTable target = new HTable(UTIL.getConfiguration(), otherTable);
+    assertTrue("Didn't complete update to target table!", completed);
+    assertEquals("Didn't find inserted row", 1, getKeyValueCount(target));
+    target.close();
+
+    UTIL.shutdownMiniCluster();
+  }
+
+  /**
+   * Count the number of keyvalue in the table. Scans all possible versions
+   * @param table table to scan
+   * @return number of keyvalues over all rows in the table
+   * @throws IOException
+   */
+  private int getKeyValueCount(HTable table) throws IOException {
+    Scan scan = new Scan();
+    scan.setMaxVersions(Integer.MAX_VALUE - 1);
+
+    ResultScanner results = table.getScanner(scan);
+    int count = 0;
+    for (Result res : results) {
+      count += res.list().size();
+      System.out.println(count + ") " + res);
+    }
+    results.close();
+
+    return count;
+  }
+}