HBASE-26714 Introduce path configuration for system coprocessors (#4069)

Signed-off-by: Ankit Singhal <ankit@apache.org>
Signed-off-by: Wellington Ramos Chevreuil <wchevreuil@apache.org>

hbase-common/src/test/java/org/apache/hadoop/hbase/util/ClassLoaderTestHelper.java

@@ -213,7 +213,7 @@ public final class ClassLoaderTestHelper {
     LOG.info("Adding jar file to outer jar file completed");
   }
 
-  static String localDirPath(Configuration conf) {
+  public static String localDirPath(Configuration conf) {
     return conf.get(ClassLoaderBase.LOCAL_DIR_KEY)
       + File.separator + "jars" + File.separator;
   }

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java

@@ -46,6 +46,7 @@ import org.apache.hadoop.hbase.ipc.RpcServer;
 import org.apache.hadoop.hbase.security.User;
 import org.apache.hadoop.hbase.util.CoprocessorClassLoader;
 import org.apache.hadoop.hbase.util.SortedList;
+import org.apache.hbase.thirdparty.com.google.common.base.Strings;
 
 /**
  * Provides the common setup framework and runtime services for coprocessor
@@ -144,14 +145,22 @@ public abstract class CoprocessorHost<C extends Coprocessor, E extends Coprocess
 
     int currentSystemPriority = Coprocessor.PRIORITY_SYSTEM;
     for (String className : defaultCPClasses) {
-      String[] classNameAndPriority = className.split("\\|");
+      // After HBASE-23710 and HBASE-26714 when configuring for system coprocessor, we accept
+      // an optional format of className|priority|path
+      String[] classNameToken = className.split("\\|");
       boolean hasPriorityOverride = false;
-      className = classNameAndPriority[0];
+      boolean hasPath = false;
+      className = classNameToken[0];
       int overridePriority = Coprocessor.PRIORITY_SYSTEM;
-      if (classNameAndPriority.length > 1){
-        overridePriority = Integer.parseInt(classNameAndPriority[1]);
+      Path path = null;
+      if (classNameToken.length > 1 && !Strings.isNullOrEmpty(classNameToken[1])) {
+        overridePriority = Integer.parseInt(classNameToken[1]);
         hasPriorityOverride = true;
       }
+      if (classNameToken.length > 2 && !Strings.isNullOrEmpty(classNameToken[2])) {
+        path = new Path(classNameToken[2].trim());
+        hasPath = true;
+      }
       className = className.trim();
       if (findCoprocessor(className) != null) {
         // If already loaded will just continue
@@ -159,8 +168,13 @@ public abstract class CoprocessorHost<C extends Coprocessor, E extends Coprocess
         continue;
       }
       ClassLoader cl = this.getClass().getClassLoader();
-      Thread.currentThread().setContextClassLoader(cl);
       try {
+        // override the class loader if a path for the system coprocessor is provided.
+        if (hasPath) {
+          cl = CoprocessorClassLoader.getClassLoader(path, this.getClass().getClassLoader(),
+            pathPrefix, conf);
+        }
+        Thread.currentThread().setContextClassLoader(cl);
         implClass = cl.loadClass(className);
         int coprocPriority = hasPriorityOverride ? overridePriority : currentSystemPriority;
         // Add coprocessors as we go to guard against case where a coprocessor is specified twice

hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorHost.java

@@ -20,6 +20,7 @@ package org.apache.hadoop.hbase.coprocessor;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 
+import java.io.File;
 import java.lang.reflect.InvocationTargetException;
 
 import org.apache.hadoop.conf.Configuration;
@@ -27,8 +28,10 @@ import org.apache.hadoop.hbase.Abortable;
 import org.apache.hadoop.hbase.Coprocessor;
 import org.apache.hadoop.hbase.CoprocessorEnvironment;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseCommonTestingUtil;
 import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
+import org.apache.hadoop.hbase.util.ClassLoaderTestHelper;
 import org.junit.Assert;
 import org.junit.ClassRule;
 import org.junit.Test;
@@ -41,6 +44,8 @@ public class TestCoprocessorHost {
   public static final HBaseClassTestRule CLASS_RULE =
       HBaseClassTestRule.forClass(TestCoprocessorHost.class);
 
+  private static final HBaseCommonTestingUtil TEST_UTIL = new HBaseCommonTestingUtil();
+
   /**
    * An {@link Abortable} implementation for tests.
    */
@@ -50,7 +55,7 @@ public class TestCoprocessorHost {
     @Override
     public void abort(String why, Throwable e) {
       this.aborted = true;
-      Assert.fail();
+      Assert.fail(e.getMessage());
     }
 
     @Override
@@ -97,6 +102,108 @@ public class TestCoprocessorHost {
     assertEquals(overridePriority, simpleEnv_v3.getPriority());
   }
 
+  @Test
+  public void testLoadSystemCoprocessorWithPath() throws Exception {
+    Configuration conf = TEST_UTIL.getConfiguration();
+    final String key = "KEY";
+    final String testClassName = "TestSystemCoprocessor";
+    final String testClassNameWithPriorityAndPath = testClassName + "PriorityAndPath";
+
+    File jarFile = buildCoprocessorJar(testClassName);
+    File jarFileWithPriorityAndPath = buildCoprocessorJar(testClassNameWithPriorityAndPath);
+
+    try {
+      CoprocessorHost<RegionCoprocessor, CoprocessorEnvironment<RegionCoprocessor>> host;
+      host = new CoprocessorHostForTest<>(conf);
+
+      // make a string of coprocessor with only priority
+      int overridePriority = Integer.MAX_VALUE - 1;
+      final String coprocessorWithPriority =
+        SimpleRegionObserverV3.class.getName() + "|" + overridePriority;
+      // make a string of coprocessor with path but no priority
+      final String coprocessorWithPath =
+        String.format("%s|%s|%s", testClassName, "", jarFile.getAbsolutePath());
+      // make a string of coprocessor with priority and path
+      final String coprocessorWithPriorityAndPath = String
+        .format("%s|%s|%s", testClassNameWithPriorityAndPath, (overridePriority - 1),
+          jarFileWithPriorityAndPath.getAbsolutePath());
+
+      // Try and load a system coprocessors
+      conf.setStrings(key, SimpleRegionObserverV2.class.getName(), coprocessorWithPriority,
+        coprocessorWithPath, coprocessorWithPriorityAndPath);
+      host.loadSystemCoprocessors(conf, key);
+
+      // first loaded system coprocessor with default priority
+      CoprocessorEnvironment<?> simpleEnv =
+        host.findCoprocessorEnvironment(SimpleRegionObserverV2.class.getName());
+      assertNotNull(simpleEnv);
+      assertEquals(Coprocessor.PRIORITY_SYSTEM, simpleEnv.getPriority());
+
+      // external system coprocessor with default priority
+      CoprocessorEnvironment<?> coprocessorEnvironmentWithPath =
+        host.findCoprocessorEnvironment(testClassName);
+      assertNotNull(coprocessorEnvironmentWithPath);
+      assertEquals(Coprocessor.PRIORITY_SYSTEM + 1, coprocessorEnvironmentWithPath.getPriority());
+
+      // system coprocessor with configured priority
+      CoprocessorEnvironment<?> coprocessorEnvironmentWithPriority =
+        host.findCoprocessorEnvironment(SimpleRegionObserverV3.class.getName());
+      assertNotNull(coprocessorEnvironmentWithPriority);
+      assertEquals(overridePriority, coprocessorEnvironmentWithPriority.getPriority());
+
+      // external system coprocessor with override priority
+      CoprocessorEnvironment<?> coprocessorEnvironmentWithPriorityAndPath =
+        host.findCoprocessorEnvironment(testClassNameWithPriorityAndPath);
+      assertNotNull(coprocessorEnvironmentWithPriorityAndPath);
+      assertEquals(overridePriority - 1, coprocessorEnvironmentWithPriorityAndPath.getPriority());
+    } finally {
+      if (jarFile.exists()) {
+        jarFile.delete();
+      }
+      if (jarFileWithPriorityAndPath.exists()) {
+        jarFileWithPriorityAndPath.delete();
+      }
+    }
+  }
+
+  @Test(expected = AssertionError.class)
+  public void testLoadSystemCoprocessorWithPathDoesNotExist() throws Exception {
+    Configuration conf = TEST_UTIL.getConfiguration();
+    final String key = "KEY";
+    final String testClassName = "TestSystemCoprocessor";
+
+    CoprocessorHost<RegionCoprocessor, CoprocessorEnvironment<RegionCoprocessor>> host;
+    host = new CoprocessorHostForTest<>(conf);
+
+    // make a string of coprocessor with path but no priority
+    final String coprocessorWithPath = testClassName + "||" + testClassName + ".jar";
+
+    // Try and load a system coprocessors
+    conf.setStrings(key, coprocessorWithPath);
+    // when loading non-exist with CoprocessorHostForTest host, it aborts with AssertionError
+    host.loadSystemCoprocessors(conf, key);
+  }
+
+  @Test(expected = AssertionError.class)
+  public void testLoadSystemCoprocessorWithPathDoesNotExistAndPriority() throws Exception {
+    Configuration conf = TEST_UTIL.getConfiguration();
+    final String key = "KEY";
+    final String testClassName = "TestSystemCoprocessor";
+
+    CoprocessorHost<RegionCoprocessor, CoprocessorEnvironment<RegionCoprocessor>> host;
+    host = new CoprocessorHostForTest<>(conf);
+
+    int overridePriority = Integer.MAX_VALUE - 1;
+    // make a string of coprocessor with path and priority
+    final String coprocessor =
+      testClassName + "|" + overridePriority + "|" + testClassName + ".jar";
+
+    // Try and load a system coprocessors
+    conf.setStrings(key, coprocessor);
+    // when loading non-exist coprocessor, it aborts with AssertionError
+    host.loadSystemCoprocessors(conf, key);
+  }
+
   public static class SimpleRegionObserverV2 extends SimpleRegionObserver { }
 
   public static class SimpleRegionObserverV3 extends SimpleRegionObserver {
@@ -128,4 +235,11 @@ public class TestCoprocessorHost {
       return new BaseEnvironment<>(instance, priority, 0, cpHostConf);
     }
   }
+
+  private File buildCoprocessorJar(String className) throws Exception {
+    String dataTestDir = TEST_UTIL.getDataTestDir().toString();
+    String code = String.format("import org.apache.hadoop.hbase.coprocessor.*; public class %s"
+      + " implements RegionCoprocessor {}", className);
+    return ClassLoaderTestHelper.buildJar(dataTestDir, className, code);
+  }
 }