[GitHub] [helix] narendly commented on a change in pull request #700: Call session aware createEphemeral to create live instance.

[GitBox <gi...@apache.org>]

narendly commented on a change in pull request #700: Call session aware createEphemeral to create live instance.
URL: https://github.com/apache/helix/pull/700#discussion_r369971790
 
 

 ##########
 File path: helix-core/src/test/java/org/apache/helix/manager/zk/TestParticipantManager.java
 ##########
 @@ -0,0 +1,182 @@
+package org.apache.helix.manager.zk;
+
+/*
+ * 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.
+ */
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Semaphore;
+
+import org.apache.helix.PreConnectCallback;
+import org.apache.helix.PropertyKey;
+import org.apache.helix.TestHelper;
+import org.apache.helix.ZkTestHelper;
+import org.apache.helix.common.ZkTestBase;
+import org.apache.helix.integration.manager.MockParticipantManager;
+import org.apache.helix.model.LiveInstance;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+
+public class TestParticipantManager extends ZkTestBase {
+  private static Logger LOG = LoggerFactory.getLogger(TestParticipantManager.class);
+
+  /*
+   * Simulates zk session expiry before creating live instance in participant manager. This test
+   * makes sure the session aware create ephemeral API is called.
+   * What this test does is:
+   * 1. Sets up live instance with session S0
+   * 2. Expires S0 and gets new session S1
+   * 3. S1 is blocked before creating live instance in participant manager
+   * 4. Expires S1 and gets new session S2
+   * 5. Proceeds S1 to create live instance, which will fail because session S1 is expired
+   * 6. Proceeds S2 to create live instance, which will succeed
+   */
+  @Test
+  public void testSessionExpiryCreateLiveInstance() throws Exception {
+    final String className = TestHelper.getTestClassName();
+    final String methodName = TestHelper.getTestMethodName();
+    final String clusterName = className + "_" + methodName;
+
+    final ZKHelixDataAccessor accessor =
+        new ZKHelixDataAccessor(clusterName, new ZkBaseDataAccessor<>(ZK_ADDR));
+    final PropertyKey.Builder keyBuilder = accessor.keyBuilder();
+
+    TestHelper.setupCluster(clusterName, ZK_ADDR,
+        12918, // participant port
+        "localhost", // participant name prefix
+        "TestDB", // resource name prefix
+        1, // resources
+        10, // partitions per resource
+        5, // number of nodes
+        3, // replicas
+        "MasterSlave",
+        true); // do rebalance
+
+    final String instanceName = "localhost_12918";
+    final MockParticipantManager manager =
+        new MockParticipantManager(ZK_ADDR, clusterName, instanceName);
+
+    manager.syncStart();
+
+    final LiveInstance liveInstance = accessor.getProperty(keyBuilder.liveInstance(instanceName));
+    final long originalCreationTime = liveInstance.getStat().getCreationTime();
+    final String originalSessionId = manager.getSessionId();
+
+    // Verify current live instance.
+    Assert.assertNotNull(liveInstance);
+    Assert.assertEquals(liveInstance.getEphemeralOwner(), originalSessionId);
+
+    final CountDownLatch startCountdown = new CountDownLatch(1);
+    final CountDownLatch endCountdown = new CountDownLatch(1);
+    final Semaphore semaphore = new Semaphore(0);
+    manager.addPreConnectCallback(
+        new BlockingPreConnectCallback(instanceName, startCountdown, endCountdown, semaphore));
+
+    // Expire S0 and new session S1 will be created.
+    ZkTestHelper.asyncExpireSession(manager.getZkClient());
+
+    // Wait for onPreConnect to start
+    semaphore.acquire();
+
+    // New session S1 should not be equal to S0.
+    Assert.assertFalse(originalSessionId.equals(manager.getSessionId()));
+
+    // Live instance should be gone as original session S0 is expired.
+    Assert.assertNull(accessor.getProperty(keyBuilder.liveInstance(instanceName)));
+
+    final String lastSessionId = manager.getSessionId();
+
+    // Expire S1 when S1 is blocked in onPreConnect().
+    // New session S2 will be created.
+    ZkTestHelper.asyncExpireSession(manager.getZkClient());
+
+    TestHelper.verify(
+        () -> !(ZKUtil.toHexSessionId(manager.getZkClient().getSessionId()).equals(lastSessionId)),
+        3000L);
+
+    // New session S2 should not be equal to S1.
+    final String latestSessionId = ZKUtil.toHexSessionId(manager.getZkClient().getSessionId());
+    Assert.assertFalse(lastSessionId.equals(latestSessionId));
+
+    // Proceed S1 to create live instance, which will fail.
+    startCountdown.countDown();
+
+    // Wait until S1's handling new session is completed.
+    semaphore.acquire();
 
 Review comment:
   Does this really wait? At this point isn't `release()` called by S2?

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