From 7395ffac447bdb159b5c9a2bc65f95af0eea11fe Mon Sep 17 00:00:00 2001
From: tedyu <yuzhihong@gmail.com>
Date: Mon, 5 Nov 2018 08:29:04 -0800
Subject: [PATCH] HBASE-21247 Custom WAL Provider cannot be specified by
 configuration whose value is outside the enums in Providers

---
 .../apache/hadoop/hbase/wal/WALFactory.java   | 14 +++++++++--
 .../hadoop/hbase/wal/IOTestProvider.java      |  5 +++-
 .../hadoop/hbase/wal/TestWALFactory.java      | 24 +++++++++++++++++++
 3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALFactory.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALFactory.java
index 0e6e3657dd5..8bde6d20011 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALFactory.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALFactory.java
@@ -260,8 +260,18 @@ public class WALFactory {
       if (provider != null) {
         return provider;
       }
-      provider = createProvider(getProviderClass(META_WAL_PROVIDER,
-          conf.get(WAL_PROVIDER, DEFAULT_WAL_PROVIDER)));
+      Class<? extends WALProvider> clz = null;
+      if (conf.get(META_WAL_PROVIDER) == null) {
+        try {
+          clz = conf.getClass(WAL_PROVIDER, Providers.defaultProvider.clazz, WALProvider.class);
+        } catch (Throwable t) {
+          // the WAL provider should be an enum. Proceed
+        }
+      } 
+      if (clz == null){
+        clz = getProviderClass(META_WAL_PROVIDER, conf.get(WAL_PROVIDER, DEFAULT_WAL_PROVIDER));
+      }
+      provider = createProvider(clz);
       provider.init(this, conf, AbstractFSWALProvider.META_WAL_PROVIDER_ID);
       provider.addWALActionsListener(new MetricsWAL());
       if (metaProvider.compareAndSet(null, provider)) {
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/IOTestProvider.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/IOTestProvider.java
index 453b742f9be..d062c77cb33 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/IOTestProvider.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/IOTestProvider.java
@@ -27,6 +27,8 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
@@ -87,6 +89,7 @@ public class IOTestProvider implements WALProvider {
   private volatile FSHLog log;
 
   private String providerId;
+  protected AtomicBoolean initialized = new AtomicBoolean(false);
 
   private List<WALActionsListener> listeners = new ArrayList<>();
   /**
@@ -97,7 +100,7 @@ public class IOTestProvider implements WALProvider {
    */
   @Override
   public void init(WALFactory factory, Configuration conf, String providerId) throws IOException {
-    if (factory != null) {
+    if (!initialized.compareAndSet(false, true)) {
       throw new IllegalStateException("WALProvider.init should only be called once.");
     }
     this.factory = factory;
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALFactory.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALFactory.java
index a20a0717df5..8fbe09dd30b 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALFactory.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALFactory.java
@@ -742,4 +742,28 @@ public class TestWALFactory {
         WALFactory.WAL_PROVIDER, Providers.multiwal.name());
     assertEquals(Providers.multiwal.clazz, multiwalProviderClass);
   }
+
+  @Test
+  public void testCustomProvider() throws IOException {
+    final Configuration config = new Configuration();
+    config.set(WALFactory.WAL_PROVIDER, IOTestProvider.class.getName());
+    final WALFactory walFactory = new WALFactory(config, this.currentServername.toString());
+    Class<? extends WALProvider> walProvider = walFactory.getProviderClass(
+        WALFactory.WAL_PROVIDER, Providers.filesystem.name());
+    assertEquals(IOTestProvider.class, walProvider);
+    WALProvider metaWALProvider = walFactory.getMetaProvider();
+    assertEquals(IOTestProvider.class, metaWALProvider.getClass());
+  }
+
+  @Test
+  public void testCustomMetaProvider() throws IOException {
+    final Configuration config = new Configuration();
+    config.set(WALFactory.META_WAL_PROVIDER, IOTestProvider.class.getName());
+    final WALFactory walFactory = new WALFactory(config, this.currentServername.toString());
+    Class<? extends WALProvider> walProvider = walFactory.getProviderClass(
+        WALFactory.WAL_PROVIDER, Providers.filesystem.name());
+    assertEquals(Providers.filesystem.clazz, walProvider);
+    WALProvider metaWALProvider = walFactory.getMetaProvider();
+    assertEquals(IOTestProvider.class, metaWALProvider.getClass());
+  }
 }