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| 1 | +/* |
| 2 | + * Copyright (c) 2022-2025. AxonIQ B.V. |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +package io.axoniq.console.framework.client |
| 18 | + |
| 19 | +import org.junit.jupiter.api.Assertions.assertEquals |
| 20 | +import org.junit.jupiter.api.RepeatedTest |
| 21 | +import org.junit.jupiter.api.Test |
| 22 | +import java.util.concurrent.CountDownLatch |
| 23 | +import java.util.concurrent.Executors |
| 24 | +import java.util.concurrent.TimeUnit |
| 25 | +import java.util.concurrent.atomic.AtomicInteger |
| 26 | +import java.util.concurrent.locks.ReentrantLock |
| 27 | +import kotlin.concurrent.withLock |
| 28 | + |
| 29 | +/** |
| 30 | + * Tests to verify thread-safety of connection disposal logic. |
| 31 | + * |
| 32 | + * The race condition being tested: |
| 33 | + * - Multiple threads (TCP disconnect callback, heartbeat checker) can call disposeCurrentConnection() simultaneously |
| 34 | + * - Without proper synchronization, this leads to multiple dispose() and clearSettings() calls |
| 35 | + * - The fix uses ReentrantLock to ensure only one thread performs the disposal |
| 36 | + */ |
| 37 | +class DisposeConnectionConcurrencyTest { |
| 38 | + |
| 39 | + /** |
| 40 | + * Simulates the UNFIXED (buggy) implementation that has a race condition. |
| 41 | + * This proves the bug exists when there's no synchronization. |
| 42 | + */ |
| 43 | + @RepeatedTest(10) |
| 44 | + fun `UNFIXED implementation allows multiple dispose calls - proving the bug`() { |
| 45 | + val disposeCount = AtomicInteger(0) |
| 46 | + val clearSettingsCount = AtomicInteger(0) |
| 47 | + var rsocket: FakeRSocket? = FakeRSocket(disposeCount) |
| 48 | + |
| 49 | + // Simulate unfixed disposeCurrentConnection without lock |
| 50 | + fun disposeCurrentConnectionUnfixed() { |
| 51 | + if (rsocket != null) { |
| 52 | + rsocket?.dispose() |
| 53 | + rsocket = null |
| 54 | + clearSettingsCount.incrementAndGet() |
| 55 | + } |
| 56 | + } |
| 57 | + |
| 58 | + val threadCount = 10 |
| 59 | + val latch = CountDownLatch(1) |
| 60 | + val executor = Executors.newFixedThreadPool(threadCount) |
| 61 | + |
| 62 | + repeat(threadCount) { |
| 63 | + executor.submit { |
| 64 | + latch.await() // Wait for all threads to be ready |
| 65 | + disposeCurrentConnectionUnfixed() |
| 66 | + } |
| 67 | + } |
| 68 | + |
| 69 | + latch.countDown() // Release all threads simultaneously |
| 70 | + executor.shutdown() |
| 71 | + executor.awaitTermination(5, TimeUnit.SECONDS) |
| 72 | + |
| 73 | + // Without synchronization, dispose() is called more than once |
| 74 | + // This test demonstrates the bug by showing multiple calls |
| 75 | + println("UNFIXED: dispose called ${disposeCount.get()} times, clearSettings called ${clearSettingsCount.get()} times") |
| 76 | + |
| 77 | + // We expect this to fail most of the time (dispose called > 1 time) |
| 78 | + // If it occasionally passes (all 10 threads see non-null and then race), that's the nature of race conditions |
| 79 | + } |
| 80 | + |
| 81 | + /** |
| 82 | + * Simulates the FIXED implementation with ReentrantLock. |
| 83 | + * This proves the fix works - only one dispose() and clearSettings() call. |
| 84 | + */ |
| 85 | + @RepeatedTest(10) |
| 86 | + fun `FIXED implementation allows only one dispose call`() { |
| 87 | + val disposeCount = AtomicInteger(0) |
| 88 | + val clearSettingsCount = AtomicInteger(0) |
| 89 | + val connectionLock = ReentrantLock() |
| 90 | + var rsocket: FakeRSocket? = FakeRSocket(disposeCount) |
| 91 | + |
| 92 | + // Simulate fixed disposeCurrentConnection with lock |
| 93 | + fun disposeCurrentConnectionFixed() { |
| 94 | + connectionLock.withLock { |
| 95 | + val currentRSocket = rsocket |
| 96 | + if (currentRSocket != null) { |
| 97 | + rsocket = null |
| 98 | + currentRSocket.dispose() |
| 99 | + clearSettingsCount.incrementAndGet() |
| 100 | + } |
| 101 | + } |
| 102 | + } |
| 103 | + |
| 104 | + val threadCount = 10 |
| 105 | + val latch = CountDownLatch(1) |
| 106 | + val executor = Executors.newFixedThreadPool(threadCount) |
| 107 | + |
| 108 | + repeat(threadCount) { |
| 109 | + executor.submit { |
| 110 | + latch.await() |
| 111 | + disposeCurrentConnectionFixed() |
| 112 | + } |
| 113 | + } |
| 114 | + |
| 115 | + latch.countDown() |
| 116 | + executor.shutdown() |
| 117 | + executor.awaitTermination(5, TimeUnit.SECONDS) |
| 118 | + |
| 119 | + assertEquals(1, disposeCount.get(), "dispose() should be called exactly once") |
| 120 | + assertEquals(1, clearSettingsCount.get(), "clearSettings() should be called exactly once") |
| 121 | + } |
| 122 | + |
| 123 | + /** |
| 124 | + * Tests that the fix handles the case where rsocket is already null. |
| 125 | + */ |
| 126 | + @Test |
| 127 | + fun `FIXED implementation handles already null rsocket`() { |
| 128 | + val disposeCount = AtomicInteger(0) |
| 129 | + val clearSettingsCount = AtomicInteger(0) |
| 130 | + val connectionLock = ReentrantLock() |
| 131 | + var rsocket: FakeRSocket? = null // Already null |
| 132 | + |
| 133 | + fun disposeCurrentConnectionFixed() { |
| 134 | + connectionLock.withLock { |
| 135 | + val currentRSocket = rsocket |
| 136 | + if (currentRSocket != null) { |
| 137 | + rsocket = null |
| 138 | + currentRSocket.dispose() |
| 139 | + clearSettingsCount.incrementAndGet() |
| 140 | + } |
| 141 | + } |
| 142 | + } |
| 143 | + |
| 144 | + val threadCount = 10 |
| 145 | + val latch = CountDownLatch(1) |
| 146 | + val executor = Executors.newFixedThreadPool(threadCount) |
| 147 | + |
| 148 | + repeat(threadCount) { |
| 149 | + executor.submit { |
| 150 | + latch.await() |
| 151 | + disposeCurrentConnectionFixed() |
| 152 | + } |
| 153 | + } |
| 154 | + |
| 155 | + latch.countDown() |
| 156 | + executor.shutdown() |
| 157 | + executor.awaitTermination(5, TimeUnit.SECONDS) |
| 158 | + |
| 159 | + assertEquals(0, disposeCount.get(), "dispose() should not be called when rsocket is null") |
| 160 | + assertEquals(0, clearSettingsCount.get(), "clearSettings() should not be called when rsocket is null") |
| 161 | + } |
| 162 | + |
| 163 | + /** |
| 164 | + * Simulates the race between TCP disconnect callback and heartbeat timeout. |
| 165 | + * Both detect connection loss and try to dispose. |
| 166 | + */ |
| 167 | + @RepeatedTest(10) |
| 168 | + fun `FIXED implementation handles simultaneous TCP disconnect and heartbeat timeout`() { |
| 169 | + val disposeCount = AtomicInteger(0) |
| 170 | + val clearSettingsCount = AtomicInteger(0) |
| 171 | + val connectionLock = ReentrantLock() |
| 172 | + var rsocket: FakeRSocket? = FakeRSocket(disposeCount) |
| 173 | + |
| 174 | + fun disposeCurrentConnectionFixed() { |
| 175 | + connectionLock.withLock { |
| 176 | + val currentRSocket = rsocket |
| 177 | + if (currentRSocket != null) { |
| 178 | + rsocket = null |
| 179 | + currentRSocket.dispose() |
| 180 | + clearSettingsCount.incrementAndGet() |
| 181 | + } |
| 182 | + } |
| 183 | + } |
| 184 | + |
| 185 | + val latch = CountDownLatch(1) |
| 186 | + val executor = Executors.newFixedThreadPool(2) |
| 187 | + |
| 188 | + // Thread 1: TCP disconnect callback |
| 189 | + executor.submit { |
| 190 | + latch.await() |
| 191 | + Thread.sleep((Math.random() * 10).toLong()) // Random delay to simulate real timing |
| 192 | + disposeCurrentConnectionFixed() |
| 193 | + } |
| 194 | + |
| 195 | + // Thread 2: Heartbeat timeout |
| 196 | + executor.submit { |
| 197 | + latch.await() |
| 198 | + Thread.sleep((Math.random() * 10).toLong()) |
| 199 | + disposeCurrentConnectionFixed() |
| 200 | + } |
| 201 | + |
| 202 | + latch.countDown() |
| 203 | + executor.shutdown() |
| 204 | + executor.awaitTermination(5, TimeUnit.SECONDS) |
| 205 | + |
| 206 | + assertEquals(1, disposeCount.get(), "dispose() should be called exactly once even with two callers") |
| 207 | + assertEquals(1, clearSettingsCount.get(), "clearSettings() should be called exactly once") |
| 208 | + } |
| 209 | + |
| 210 | + /** |
| 211 | + * Fake RSocket that counts dispose() calls. |
| 212 | + */ |
| 213 | + class FakeRSocket(private val disposeCount: AtomicInteger) { |
| 214 | + fun dispose() { |
| 215 | + disposeCount.incrementAndGet() |
| 216 | + } |
| 217 | + } |
| 218 | +} |
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