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Merge pull request #1460 from himanshug/leader_shutdown
Leader to give up leadership lock on graceful shutdown
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80 changes: 80 additions & 0 deletions
80
extended/src/test/java/io/kubernetes/client/extended/leaderelection/LeaderElectorTest.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,80 @@ | ||
| /* | ||
| Copyright 2020 The Kubernetes Authors. | ||
| Licensed 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 io.kubernetes.client.extended.leaderelection; | ||
|
|
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| import java.time.Duration; | ||
| import java.util.concurrent.CountDownLatch; | ||
| import java.util.concurrent.TimeUnit; | ||
| import org.junit.Test; | ||
|
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| /** Leader Election tests using "simulated" locks created by {@link LockSmith} */ | ||
| public class LeaderElectorTest { | ||
| /** | ||
| * Tests that when a leader candidate is stopped gracefully, second candidate immediately becomes | ||
| * leader. | ||
| */ | ||
| @Test(timeout = 20000L) | ||
| public void testLeaderGracefulShutdown() throws Exception { | ||
| LockSmith lockSmith = new LockSmith(); | ||
|
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| CountDownLatch startBeingLeader1 = new CountDownLatch(1); | ||
| CountDownLatch stopBeingLeader1 = new CountDownLatch(1); | ||
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| LeaderElector leaderElector1 = | ||
| makeAndRunLeaderElectorAsync(lockSmith, "candidate1", startBeingLeader1, stopBeingLeader1); | ||
|
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| // wait for candidate1 to become leader | ||
| startBeingLeader1.await(); | ||
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| CountDownLatch startBeingLeader2 = new CountDownLatch(1); | ||
| CountDownLatch stopBeingLeader2 = new CountDownLatch(1); | ||
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| LeaderElector leaderElector2 = | ||
| makeAndRunLeaderElectorAsync(lockSmith, "candidate2", startBeingLeader2, stopBeingLeader2); | ||
|
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| leaderElector1.close(); | ||
|
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| // ensure stopBeingLeader hook is called | ||
| stopBeingLeader1.await(); | ||
|
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| // wait for candidate2 to become leader | ||
| startBeingLeader2.await(); | ||
|
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| leaderElector2.close(); | ||
| } | ||
|
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| private LeaderElector makeAndRunLeaderElectorAsync( | ||
| LockSmith lockSmith, | ||
| String lockIdentity, | ||
| CountDownLatch startBeingLeader, | ||
| CountDownLatch stopBeingLeader) { | ||
| LeaderElectionConfig leaderElectionConfig = | ||
| new LeaderElectionConfig( | ||
| lockSmith.makeLock(lockIdentity), | ||
| Duration.ofMillis(TimeUnit.MINUTES.toMillis(1)), | ||
| Duration.ofMillis(TimeUnit.SECONDS.toMillis(51)), | ||
| Duration.ofMillis(TimeUnit.SECONDS.toMillis(3))); | ||
| LeaderElector leaderElector = new LeaderElector(leaderElectionConfig); | ||
|
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| Thread thread = | ||
| new Thread( | ||
| () -> | ||
| leaderElector.run( | ||
| () -> startBeingLeader.countDown(), () -> stopBeingLeader.countDown()), | ||
| String.format("%s-leader-elector-main", lockIdentity)); | ||
| thread.setDaemon(true); | ||
| thread.start(); | ||
|
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| return leaderElector; | ||
| } | ||
| } |
84 changes: 84 additions & 0 deletions
84
extended/src/test/java/io/kubernetes/client/extended/leaderelection/LockSmith.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,84 @@ | ||
| /* | ||
| Copyright 2020 The Kubernetes Authors. | ||
| Licensed 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 io.kubernetes.client.extended.leaderelection; | ||
|
|
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| import io.kubernetes.client.openapi.ApiException; | ||
| import java.net.HttpURLConnection; | ||
| import java.util.concurrent.atomic.AtomicReference; | ||
|
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| /** Makes simulated {@link Lock} objects that behave as if they were backed by real API server. */ | ||
| public class LockSmith { | ||
| private AtomicReference<Resource> lockResourceRef = new AtomicReference<>(); | ||
|
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| public Lock makeLock(String identity) { | ||
| return new SimulatedLock(identity); | ||
| } | ||
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| private class SimulatedLock implements Lock { | ||
| private final String identity; | ||
|
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| public SimulatedLock(String identity) { | ||
| this.identity = identity; | ||
| } | ||
|
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| @Override | ||
| public LeaderElectionRecord get() throws ApiException { | ||
| if (lockResourceRef.get() == null) { | ||
| throw new ApiException("Record Not Found", HttpURLConnection.HTTP_NOT_FOUND, null, null); | ||
| } | ||
|
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| return lockResourceRef.get().record; | ||
| } | ||
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| @Override | ||
| public boolean create(LeaderElectionRecord record) { | ||
| return lockResourceRef.compareAndSet(null, new Resource(record)); | ||
| } | ||
|
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| @Override | ||
| public boolean update(LeaderElectionRecord record) { | ||
| Resource res = lockResourceRef.get(); | ||
| if (res == null) { | ||
| return false; | ||
| } else { | ||
| Resource newResource = new Resource(res.version + 1, record); | ||
| return lockResourceRef.compareAndSet(res, newResource); | ||
| } | ||
| } | ||
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| @Override | ||
| public String identity() { | ||
| return identity; | ||
| } | ||
|
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| @Override | ||
| public String describe() { | ||
| return "simulated/lock"; | ||
| } | ||
| } | ||
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| private static class Resource { | ||
| final int version; | ||
| final LeaderElectionRecord record; | ||
|
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| public Resource(LeaderElectionRecord record) { | ||
| this.version = 0; | ||
| this.record = record; | ||
| } | ||
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| public Resource(int version, LeaderElectionRecord record) { | ||
| this.version = version; | ||
| this.record = record; | ||
| } | ||
| } | ||
| } |