HADOOP-10085. CompositeService should allow adding services while being inited. (Steve Loughran via kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1563694 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -313,6 +313,9 @@ Release 2.4.0 - UNRELEASED
 
     HADOOP-10320. Javadoc in InterfaceStability.java lacks final </ul>.
     (René Nyffenegger via cnauroth)
+    
+    HADOOP-10085. CompositeService should allow adding services while being 
+    inited. (Steve Loughran via kasha)
 
 Release 2.3.0 - UNRELEASED
 

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/service/CompositeService.java

@@ -19,7 +19,6 @@
 package org.apache.hadoop.service;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
@@ -54,13 +53,13 @@ public CompositeService(String name) {
   }
 
   /**
-   * Get an unmodifiable list of services
+   * Get a cloned list of services
    * @return a list of child services at the time of invocation -
    * added services will not be picked up.
    */
   public List<Service> getServices() {
     synchronized (serviceList) {
-      return Collections.unmodifiableList(serviceList);
+      return new ArrayList<Service>(serviceList);
     }
   }
 

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/service/TestCompositeService.java

@@ -16,26 +16,20 @@
  * limitations under the License.
  */
 
-package org.apache.hadoop.yarn.util;
+package org.apache.hadoop.service;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.service.Service.STATE;
+import org.junit.Before;
+import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.service.AbstractService;
-import org.apache.hadoop.service.BreakableService;
-import org.apache.hadoop.service.CompositeService;
-import org.apache.hadoop.service.Service;
-import org.apache.hadoop.service.ServiceStateException;
-import org.apache.hadoop.service.Service.STATE;
-import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
-import org.junit.Before;
-import org.junit.Test;
-
 public class TestCompositeService {
 
   private static final int NUM_OF_SERVICES = 5;
@@ -156,7 +150,7 @@ public void testServiceStartup() {
     try {
       serviceManager.start();
       fail("Exception should have been thrown due to startup failure of last service");
-    } catch (YarnRuntimeException e) {
+    } catch (ServiceTestRuntimeException e) {
       for (int i = 0; i < NUM_OF_SERVICES - 1; i++) {
         if (i >= FAILED_SERVICE_SEQ_NUMBER && STOP_ONLY_STARTED_SERVICES) {
           // Failed service state should be INITED
@@ -197,7 +191,7 @@ public void testServiceStop() {
     // Stop the composite service
     try {
       serviceManager.stop();
-    } catch (YarnRuntimeException e) {
+    } catch (ServiceTestRuntimeException e) {
     }
     assertInState(STATE.STOPPED, services);
   }
@@ -335,7 +329,41 @@ public void serviceInit(Configuration conf) {
 
     testService.init(new Configuration());
     assertEquals("Incorrect number of services",
-        1, testService.getServices().size());
+                 1, testService.getServices().size());
+  }
+
+  @Test(timeout = 1000)
+  public void testAddInitedSiblingInInit() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService sibling = new BreakableService();
+    sibling.init(new Configuration());
+    parent.addService(new AddSiblingService(parent,
+                                            sibling,
+                                            STATE.INITED));
+    parent.init(new Configuration());
+    parent.start();
+    parent.stop();
+    assertEquals("Incorrect number of services",
+                 2, parent.getServices().size());
+  }
+
+  @Test(timeout = 1000)
+  public void testAddUninitedSiblingInInit() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService sibling = new BreakableService();
+    parent.addService(new AddSiblingService(parent,
+                                            sibling,
+                                            STATE.INITED));
+    parent.init(new Configuration());
+    try {
+      parent.start();
+      fail("Expected an exception, got " + parent);
+    } catch (ServiceStateException e) {
+      //expected
+    }
+    parent.stop();
+    assertEquals("Incorrect number of services",
+                 2, parent.getServices().size());
   }
 
   @Test
@@ -365,6 +393,105 @@ public void serviceInit(Configuration conf) {
         2, testService.getServices().size());
   }
 
+  @Test(timeout = 1000)
+  public void testAddStartedChildBeforeInit() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService child = new BreakableService();
+    child.init(new Configuration());
+    child.start();
+    AddSiblingService.addChildToService(parent, child);
+    try {
+      parent.init(new Configuration());
+      fail("Expected an exception, got " + parent);
+    } catch (ServiceStateException e) {
+      //expected
+    }
+    parent.stop();
+  }
+
+  @Test(timeout = 1000)
+  public void testAddStoppedChildBeforeInit() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService child = new BreakableService();
+    child.init(new Configuration());
+    child.start();
+    child.stop();
+    AddSiblingService.addChildToService(parent, child);
+    try {
+      parent.init(new Configuration());
+      fail("Expected an exception, got " + parent);
+    } catch (ServiceStateException e) {
+      //expected
+    }
+    parent.stop();
+  }
+
+  @Test(timeout = 1000)
+  public void testAddStartedSiblingInStart() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService sibling = new BreakableService();
+    sibling.init(new Configuration());
+    sibling.start();
+    parent.addService(new AddSiblingService(parent,
+                                            sibling,
+                                            STATE.STARTED));
+    parent.init(new Configuration());
+    parent.start();
+    parent.stop();
+    assertEquals("Incorrect number of services",
+                 2, parent.getServices().size());
+  }
+
+  @Test(timeout = 1000)
+  public void testAddUninitedSiblingInStart() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService sibling = new BreakableService();
+    parent.addService(new AddSiblingService(parent,
+                                            sibling,
+                                            STATE.STARTED));
+    parent.init(new Configuration());
+    assertInState(STATE.NOTINITED, sibling);
+    parent.start();
+    parent.stop();
+    assertEquals("Incorrect number of services",
+                 2, parent.getServices().size());
+  }
+
+  @Test(timeout = 1000)
+  public void testAddStartedSiblingInInit() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService sibling = new BreakableService();
+    sibling.init(new Configuration());
+    sibling.start();
+    parent.addService(new AddSiblingService(parent,
+                                            sibling,
+                                            STATE.INITED));
+    parent.init(new Configuration());
+    assertInState(STATE.STARTED, sibling);
+    parent.start();
+    assertInState(STATE.STARTED, sibling);
+    parent.stop();
+    assertEquals("Incorrect number of services",
+                 2, parent.getServices().size());
+    assertInState(STATE.STOPPED, sibling);
+  }
+
+  @Test(timeout = 1000)
+  public void testAddStartedSiblingInStop() throws Throwable {
+    CompositeService parent = new CompositeService("parent");
+    BreakableService sibling = new BreakableService();
+    sibling.init(new Configuration());
+    sibling.start();
+    parent.addService(new AddSiblingService(parent,
+                                            sibling,
+                                            STATE.STOPPED));
+    parent.init(new Configuration());
+    parent.start();
+    parent.stop();
+    assertEquals("Incorrect number of services",
+                 2, parent.getServices().size());
+  }
+
   public static class CompositeServiceAddingAChild extends CompositeService{
     Service child;
 
@@ -379,7 +506,18 @@ protected void serviceInit(Configuration conf) throws Exception {
       super.serviceInit(conf);
     }
   }
-  
+
+  public static class ServiceTestRuntimeException extends RuntimeException {
+    public ServiceTestRuntimeException(String message) {
+      super(message);
+    }
+  }
+
+  /**
+   * This is a composite service that keeps a count of the number of lifecycle
+   * events called, and can be set to throw a {@link ServiceTestRuntimeException }
+   * during service start or stop
+   */
   public static class CompositeServiceImpl extends CompositeService {
 
     public static boolean isPolicyToStopOnlyStartedServices() {
@@ -408,7 +546,7 @@ protected void serviceInit(Configuration conf) throws Exception {
     @Override
     protected void serviceStart() throws Exception {
       if (throwExceptionOnStart) {
-        throw new YarnRuntimeException("Fake service start exception");
+        throw new ServiceTestRuntimeException("Fake service start exception");
       }
       counter++;
       callSequenceNumber = counter;
@@ -420,7 +558,7 @@ protected void serviceStop() throws Exception {
       counter++;
       callSequenceNumber = counter;
       if (throwExceptionOnStop) {
-        throw new YarnRuntimeException("Fake service stop exception");
+        throw new ServiceTestRuntimeException("Fake service stop exception");
       }
       super.serviceStop();
     }
@@ -457,6 +595,9 @@ public String toString() {
 
   }
 
+  /**
+   * Composite service that makes the addService method public to all
+   */
   public static class ServiceManager extends CompositeService {
 
     public void addTestService(CompositeService service) {
@@ -468,4 +609,55 @@ public ServiceManager(String name) {
     }
   }
 
+  public static class AddSiblingService extends CompositeService {
+    private final CompositeService parent;
+    private final Service serviceToAdd;
+    private STATE triggerState;
+
+    public AddSiblingService(CompositeService parent,
+                             Service serviceToAdd,
+                             STATE triggerState) {
+      super("ParentStateManipulatorService");
+      this.parent = parent;
+      this.serviceToAdd = serviceToAdd;
+      this.triggerState = triggerState;
+    }
+
+    /**
+     * Add the serviceToAdd to the parent if this service
+     * is in the state requested
+     */
+    private void maybeAddSibling() {
+      if (getServiceState() == triggerState) {
+        parent.addService(serviceToAdd);
+      }
+    }
+
+    @Override
+    protected void serviceInit(Configuration conf) throws Exception {
+      maybeAddSibling();
+      super.serviceInit(conf);
+    }
+
+    @Override
+    protected void serviceStart() throws Exception {
+      maybeAddSibling();
+      super.serviceStart();
+    }
+
+    @Override
+    protected void serviceStop() throws Exception {
+      maybeAddSibling();
+      super.serviceStop();
+    }
+
+    /**
+     * Expose addService method
+     * @param parent parent service
+     * @param child child to add
+     */
+    public static void addChildToService(CompositeService parent, Service child) {
+      parent.addService(child);
+    }
+  }
 }