MAPREDUCE-3877 Add a test to formalise the current state transitions of the yarn lifecycle

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1245918 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -102,6 +102,9 @@ Release 0.23.2 - UNRELEASED
     MAPREDUCE-3854. Fixed and reenabled tests related to MR child JVM's
     environmental variables in TestMiniMRChildTask. (Tom White via vinodkv)
 
+    MAPREDUCE-3877 Add a test to formalise the current state transitions
+    of the yarn lifecycle. (stevel)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/service/BreakableService.java

@@ -0,0 +1,123 @@
+/**
+ * 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.yarn.service;
+
+import org.apache.hadoop.conf.Configuration;
+
+/**
+ * This is a service that can be configured to break on any of the lifecycle
+ * events, so test the failure handling of other parts of the service
+ * infrastructure.
+ *
+ * It retains a counter to the number of times each entry point is called -
+ * these counters are incremented before the exceptions are raised and
+ * before the superclass state methods are invoked.
+ *
+ */
+
+
+public class BreakableService extends AbstractService {
+
+  private boolean failOnInit;
+  private boolean failOnStart;
+  private boolean failOnStop;
+  private int[] counts = new int[4];
+
+  public BreakableService() {
+    this(false, false, false);
+  }
+
+  public BreakableService(boolean failOnInit,
+                          boolean failOnStart,
+                          boolean failOnStop) {
+    super("BreakableService");
+    this.failOnInit = failOnInit;
+    this.failOnStart = failOnStart;
+    this.failOnStop = failOnStop;
+    inc(STATE.NOTINITED);
+  }
+
+  private int convert(STATE state) {
+    switch (state) {
+      case NOTINITED: return 0;
+      case INITED:    return 1;
+      case STARTED:   return 2;
+      case STOPPED:   return 3;
+      default:        return 0;
+    }
+  }
+
+  private void inc(STATE state) {
+    int index = convert(state);
+    counts[index] ++;
+  }
+
+  public int getCount(STATE state) {
+    return counts[convert(state)];
+  }
+
+  private void maybeFail(boolean fail, String action) {
+    if (fail) {
+      throw new BrokenLifecycleEvent(action);
+    }
+  }
+
+  @Override
+  public void init(Configuration conf) {
+    inc(STATE.INITED);
+    maybeFail(failOnInit, "init");
+    super.init(conf);
+  }
+
+  @Override
+  public void start() {
+    inc(STATE.STARTED);
+    maybeFail(failOnStart, "start");
+    super.start();
+  }
+
+  @Override
+  public void stop() {
+    inc(STATE.STOPPED);
+    maybeFail(failOnStop, "stop");
+    super.stop();
+  }
+
+  public void setFailOnInit(boolean failOnInit) {
+    this.failOnInit = failOnInit;
+  }
+
+  public void setFailOnStart(boolean failOnStart) {
+    this.failOnStart = failOnStart;
+  }
+
+  public void setFailOnStop(boolean failOnStop) {
+    this.failOnStop = failOnStop;
+  }
+
+  /**
+   * The exception explicitly raised on a failure
+   */
+  public static class BrokenLifecycleEvent extends RuntimeException {
+    BrokenLifecycleEvent(String action) {
+      super("Lifecycle Failure during " + action);
+    }
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/service/ServiceAssert.java

@@ -0,0 +1,49 @@
+/**
+ * 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.yarn.service;
+
+import org.junit.Assert;
+
+/**
+ * A set of assertions about the state of any service
+ */
+public class ServiceAssert extends Assert {
+
+  public static void assertServiceStateCreated(Service service) {
+    assertServiceInState(service, Service.STATE.NOTINITED);
+  }
+
+  public static void assertServiceStateInited(Service service) {
+    assertServiceInState(service, Service.STATE.INITED);
+  }
+
+  public static void assertServiceStateStarted(Service service) {
+    assertServiceInState(service, Service.STATE.STARTED);
+  }
+
+  public static void assertServiceStateStopped(Service service) {
+    assertServiceInState(service, Service.STATE.STOPPED);
+  }
+
+  public static void assertServiceInState(Service service, Service.STATE state) {
+    assertNotNull("Null service", service);
+    assertEquals("Service in wrong state: " + service, state,
+                 service.getServiceState());
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/service/TestServiceLifecycle.java

@@ -0,0 +1,194 @@
+/**
+ * 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.yarn.service;
+
+import org.apache.hadoop.conf.Configuration;
+import org.junit.Test;
+
+public class TestServiceLifecycle extends ServiceAssert {
+
+  void assertStateCount(BreakableService service,
+                        Service.STATE state,
+                        int expected) {
+    int actual = service.getCount(state);
+    if (expected != actual) {
+      fail("Expected entry count for state [" + state +"] of " + service
+               + " to be " + expected + " but was " + actual);
+    }
+  }
+
+
+  @Test
+  public void testWalkthrough() throws Throwable {
+
+    BreakableService svc = new BreakableService();
+    assertServiceStateCreated(svc);
+    assertStateCount(svc, Service.STATE.NOTINITED, 1);
+    assertStateCount(svc, Service.STATE.INITED, 0);
+    assertStateCount(svc, Service.STATE.STARTED, 0);
+    assertStateCount(svc, Service.STATE.STOPPED, 0);
+    svc.init(new Configuration());
+    assertServiceStateInited(svc);
+    assertStateCount(svc, Service.STATE.INITED, 1);
+    svc.start();
+    assertServiceStateStarted(svc);
+    assertStateCount(svc, Service.STATE.STARTED, 1);
+    svc.stop();
+    assertServiceStateStopped(svc);
+    assertStateCount(svc, Service.STATE.STOPPED, 1);
+  }
+
+  /**
+   * call init twice
+   * @throws Throwable
+   */
+  @Test
+  public void testInitTwice() throws Throwable {
+    BreakableService svc = new BreakableService();
+    svc.init(new Configuration());
+    try {
+      svc.init(new Configuration());
+      fail("Expected a failure, got " + svc);
+    } catch (IllegalStateException e) {
+      //expected
+    }
+    assertStateCount(svc, Service.STATE.INITED, 2);
+  }
+
+  /**
+   * call start twice
+   * @throws Throwable
+   */
+  @Test
+  public void testStartTwice() throws Throwable {
+    BreakableService svc = new BreakableService();
+    svc.init(new Configuration());
+    svc.start();
+    try {
+      svc.start();
+      fail("Expected a failure, got " + svc);
+    } catch (IllegalStateException e) {
+      //expected
+    }
+    assertStateCount(svc, Service.STATE.STARTED, 2);
+  }
+
+
+  /**
+   * verify that when a service is stopped more than once, no exception
+   * is thrown, and the counter is incremented
+   * this is because the state change operations happen after the counter in
+   * the subclass is incremented, even though stop is meant to be a no-op
+   * @throws Throwable
+   */
+  @Test
+  public void testStopTwice() throws Throwable {
+    BreakableService svc = new BreakableService();
+    svc.init(new Configuration());
+    svc.start();
+    svc.stop();
+    assertStateCount(svc, Service.STATE.STOPPED, 1);
+    svc.stop();
+    assertStateCount(svc, Service.STATE.STOPPED, 2);
+  }
+
+
+  /**
+   * Show that if the service failed during an init
+   * operation, it stays in the created state, even after stopping it
+   * @throws Throwable
+   */
+
+  @Test
+  public void testStopFailedInit() throws Throwable {
+    BreakableService svc = new BreakableService(true, false, false);
+    assertServiceStateCreated(svc);
+    try {
+      svc.init(new Configuration());
+      fail("Expected a failure, got " + svc);
+    } catch (BreakableService.BrokenLifecycleEvent e) {
+      //expected
+    }
+    //the service state wasn't passed
+    assertServiceStateCreated(svc);
+    assertStateCount(svc, Service.STATE.INITED, 1);
+    //now try to stop
+    svc.stop();
+    //even after the stop operation, we haven't entered the state
+    assertServiceStateCreated(svc);
+  }
+
+
+  /**
+   * Show that if the service failed during an init
+   * operation, it stays in the created state, even after stopping it
+   * @throws Throwable
+   */
+
+  @Test
+  public void testStopFailedStart() throws Throwable {
+    BreakableService svc = new BreakableService(false, true, false);
+    svc.init(new Configuration());
+    assertServiceStateInited(svc);
+    try {
+      svc.start();
+      fail("Expected a failure, got " + svc);
+    } catch (BreakableService.BrokenLifecycleEvent e) {
+      //expected
+    }
+    //the service state wasn't passed
+    assertServiceStateInited(svc);
+    assertStateCount(svc, Service.STATE.INITED, 1);
+    //now try to stop
+    svc.stop();
+    //even after the stop operation, we haven't entered the state
+    assertServiceStateInited(svc);
+  }
+
+  /**
+   * verify that when a service is stopped more than once, no exception
+   * is thrown, and the counter is incremented
+   * this is because the state change operations happen after the counter in
+   * the subclass is incremented, even though stop is meant to be a no-op
+   * @throws Throwable
+   */
+  @Test
+  public void testFailingStop() throws Throwable {
+    BreakableService svc = new BreakableService(false, false, true);
+    svc.init(new Configuration());
+    svc.start();
+    try {
+      svc.stop();
+      fail("Expected a failure, got " + svc);
+    } catch (BreakableService.BrokenLifecycleEvent e) {
+      //expected
+    }
+    assertStateCount(svc, Service.STATE.STOPPED, 1);
+    //now try again, and expect it to happen again
+    try {
+      svc.stop();
+      fail("Expected a failure, got " + svc);
+    } catch (BreakableService.BrokenLifecycleEvent e) {
+      //expected
+    }
+    assertStateCount(svc, Service.STATE.STOPPED, 2);
+  }
+
+}