From cff664c5e286bebaddd93665680fb148783b8e7a Mon Sep 17 00:00:00 2001
From: Enis Soztutar <enis@apache.org>
Date: Thu, 10 Dec 2015 19:11:57 -0800
Subject: [PATCH] HBASE-14960 Fallback to using default RPCControllerFactory if
 class cannot be loaded

---
 .../hbase/ipc/RpcControllerFactory.java       | 26 +++++++++++++++++--
 .../client/TestRpcControllerFactory.java      | 17 +++++++++++-
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcControllerFactory.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcControllerFactory.java
index f8ab23f12d4..faeca8de45d 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcControllerFactory.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/RpcControllerFactory.java
@@ -19,6 +19,8 @@ package org.apache.hadoop.hbase.ipc;
 
 import java.util.List;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.CellScannable;
 import org.apache.hadoop.hbase.CellScanner;
@@ -30,7 +32,13 @@ import org.apache.hadoop.hbase.util.ReflectionUtils;
  */
 @InterfaceAudience.Private
 public class RpcControllerFactory {
+  private static final Log LOG = LogFactory.getLog(RpcControllerFactory.class);
 
+  /**
+   * Custom RPC Controller factory allows frameworks to change the RPC controller. If the configured
+   * controller cannot be found in the classpath or loaded, we fall back to the default RPC
+   * controller factory.
+   */
   public static final String CUSTOM_CONTROLLER_CONF_KEY = "hbase.rpc.controllerfactory.class";
   protected final Configuration conf;
 
@@ -55,7 +63,21 @@ public class RpcControllerFactory {
     String rpcControllerFactoryClazz =
         configuration.get(CUSTOM_CONTROLLER_CONF_KEY,
           RpcControllerFactory.class.getName());
-    return ReflectionUtils.instantiateWithCustomCtor(rpcControllerFactoryClazz,
-      new Class[] { Configuration.class }, new Object[] { configuration });
+    try {
+      return ReflectionUtils.instantiateWithCustomCtor(rpcControllerFactoryClazz,
+        new Class[] { Configuration.class }, new Object[] { configuration });
+    } catch (UnsupportedOperationException | NoClassDefFoundError ex) {
+      // HBASE-14960: In case the RPCController is in a non-HBase jar (Phoenix), but the application
+      // is a pure HBase application, we want to fallback to the default one.
+      String msg = "Cannot load configured \"" + CUSTOM_CONTROLLER_CONF_KEY + "\" ("
+          + rpcControllerFactoryClazz + ") from hbase-site.xml, falling back to use "
+          + "default RpcControllerFactory";
+      if (LOG.isDebugEnabled()) {
+        LOG.warn(msg, ex); // if DEBUG enabled, we want the exception, but still log in WARN level
+      } else {
+        LOG.warn(msg);
+      }
+      return new RpcControllerFactory(configuration);
+    }
   }
 }
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestRpcControllerFactory.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestRpcControllerFactory.java
index c087135fe07..656dedc4368 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestRpcControllerFactory.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestRpcControllerFactory.java
@@ -19,6 +19,7 @@ package org.apache.hadoop.hbase.client;
 
 import static org.apache.hadoop.hbase.HBaseTestingUtility.fam1;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 import java.io.IOException;
 import java.util.List;
@@ -54,14 +55,17 @@ public class TestRpcControllerFactory {
       super(conf);
     }
 
+    @Override
     public PayloadCarryingRpcController newController() {
       return new CountingRpcController(super.newController());
     }
 
+    @Override
     public PayloadCarryingRpcController newController(final CellScanner cellScanner) {
       return new CountingRpcController(super.newController(cellScanner));
     }
 
+    @Override
     public PayloadCarryingRpcController newController(final List<CellScannable> cellIterables) {
       return new CountingRpcController(super.newController(cellIterables));
     }
@@ -103,7 +107,7 @@ public class TestRpcControllerFactory {
     Configuration conf = UTIL.getConfiguration();
     conf.set(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY,
       ProtobufCoprocessorService.class.getName());
-    
+
     UTIL.startMiniCluster();
   }
 
@@ -202,4 +206,15 @@ public class TestRpcControllerFactory {
     assertEquals(0, CountingRpcController.INT_PRIORITY.get());
     return counter + 1;
   }
+
+  @Test
+  public void testFallbackToDefaultRpcControllerFactory() {
+    Configuration conf = new Configuration(UTIL.getConfiguration());
+    conf.set(RpcControllerFactory.CUSTOM_CONTROLLER_CONF_KEY, "foo.bar.Baz");
+
+    // Should not fail
+    RpcControllerFactory factory = RpcControllerFactory.instantiate(conf);
+    assertNotNull(factory);
+    assertEquals(factory.getClass(), RpcControllerFactory.class);
+  }
 }
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