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HTTPCLIENT-2416 - Fix pool entry leak on late lease completion #809

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arturobernalg wants to merge 1 commit into from
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HTTPCLIENT-2416 - Fix pool entry leak on late lease completion #809

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101 changes: 101 additions & 0 deletions ...t5-testing/src/test/java/org/apache/hc/client5/testing/sync/TestConnectionManagement.java
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,13 @@

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Consumer;

import org.apache.hc.client5.http.HttpRoute;
Expand Down Expand Up @@ -63,6 +69,7 @@
import org.apache.hc.core5.io.CloseMode;
import org.apache.hc.core5.pool.PoolConcurrencyPolicy;
import org.apache.hc.core5.pool.PoolReusePolicy;
import org.apache.hc.core5.pool.PoolStats;
import org.apache.hc.core5.util.TimeValue;
import org.apache.hc.core5.util.Timeout;
import org.junit.jupiter.api.AfterEach;
Expand Down Expand Up @@ -391,4 +398,98 @@ void testConnectionTimeoutSetting() throws Exception {
connManager.close();
}

@Test
void testConnectionRequestTimeout() throws Exception {
configureServer(bootstrap -> bootstrap
.register("/random/*", new RandomHandler()));
final HttpHost target = startServer();

connManager.setMaxTotal(1);

final HttpRoute route = new HttpRoute(target, null, false);
final Timeout connRequestTimeout = Timeout.ofMicroseconds(1);

final int concurrentThreads = 10;
final CountDownLatch countDownLatch = new CountDownLatch(concurrentThreads);
final AtomicLong n = new AtomicLong(concurrentThreads * 100);

final ExecutorService executorService = Executors.newFixedThreadPool(concurrentThreads);
for (int i = 0; i < concurrentThreads; i++) {
executorService.execute(() -> {
try {
while (n.decrementAndGet() > 0) {
try {
final LeaseRequest request = connManager.lease("id1", route, connRequestTimeout, null);
final ConnectionEndpoint connectionEndpoint = request.get(connRequestTimeout);
connManager.release(connectionEndpoint, null, null);
} catch (final InterruptedException ex) {
Thread.currentThread().interrupt();
Assertions.fail("Unexpected exception", ex);
} catch (final TimeoutException | ExecutionException ignored) {
}
}
} finally {
countDownLatch.countDown();
}
});
}

Assertions.assertTrue(countDownLatch.await(TIMEOUT.getDuration(), TIMEOUT.getTimeUnit()));
Assertions.assertTrue(n.get() <= 0);

final PoolStats stats = connManager.getStats(route);
Assertions.assertEquals(0, stats.getLeased());

connManager.close();
}

@Test
void testConnectionRequestCancelLateLeaseReleased() throws Exception {
configureServer(bootstrap -> bootstrap
.register("/random/*", new RandomHandler()));
final HttpHost target = startServer();

connManager.setMaxTotal(1);

final HttpRoute route = new HttpRoute(target, null, false);
final Timeout t = Timeout.ofSeconds(5);

final LeaseRequest holdRequest = connManager.lease("hold", route, t, null);
final ConnectionEndpoint heldEndpoint = holdRequest.get(t);

final LeaseRequest pendingRequest = connManager.lease("pending", route, t, null);

connManager.release(heldEndpoint, null, null);

PoolStats stats;
final long deadline1 = System.nanoTime() + TimeUnit.SECONDS.toNanos(5);
for (;;) {
stats = connManager.getStats(route);
if (stats.getLeased() == 1) {
break;
}
if (System.nanoTime() > deadline1) {
break;
}
Thread.yield();
}
Assertions.assertEquals(1, stats.getLeased(), "Expected pending lease to complete and become leased");
Assertions.assertFalse(pendingRequest.cancel(), "Expected cancel() to lose the race once lease is completed");

final long deadline2 = System.nanoTime() + TimeUnit.SECONDS.toNanos(5);
for (;;) {
stats = connManager.getStats(route);
if (stats.getLeased() == 0) {
break;
}
if (System.nanoTime() > deadline2) {
break;
}
Thread.yield();
}
Assertions.assertEquals(0, stats.getLeased(), "Late-completed lease must not remain stranded after cancel()");

connManager.close();
}

}
54 changes: 51 additions & 3 deletions .../src/main/java/org/apache/hc/client5/http/impl/io/PoolingHttpClientConnectionManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,7 @@
import org.apache.hc.core5.annotation.Contract;
import org.apache.hc.core5.annotation.Internal;
import org.apache.hc.core5.annotation.ThreadingBehavior;
import org.apache.hc.core5.concurrent.FutureCallback;
import org.apache.hc.core5.function.Resolver;
import org.apache.hc.core5.http.ClassicHttpRequest;
import org.apache.hc.core5.http.ClassicHttpResponse;
Expand Down Expand Up @@ -369,7 +370,36 @@ public LeaseRequest lease(
if (LOG.isDebugEnabled()) {
LOG.debug("{} endpoint lease request ({}) {}", id, requestTimeout, ConnPoolSupport.formatStats(route, state, pool));
}
final Future<PoolEntry<HttpRoute, ManagedHttpClientConnection>> leaseFuture = this.pool.lease(route, state, requestTimeout, null);
final AtomicBoolean aborted = new AtomicBoolean(false);
final AtomicBoolean resultObtained = new AtomicBoolean(false);
final AtomicReference<PoolEntry<HttpRoute, ManagedHttpClientConnection>> lateEntryRef = new AtomicReference<>();
final Future<PoolEntry<HttpRoute, ManagedHttpClientConnection>> leaseFuture = this.pool.lease(
route,
state,
requestTimeout,
new FutureCallback<PoolEntry<HttpRoute, ManagedHttpClientConnection>>() {

@Override
public void completed(final PoolEntry<HttpRoute, ManagedHttpClientConnection> poolEntry) {
lateEntryRef.set(poolEntry);
if (aborted.get()) {
if (lateEntryRef.compareAndSet(poolEntry, null)) {
pool.release(poolEntry, false);
}
} else if (resultObtained.get()) {
lateEntryRef.compareAndSet(poolEntry, null);
}
}

@Override
public void failed(final Exception ex) {
}

@Override
public void cancelled() {
}

});
return new LeaseRequest() {
// Using a ReentrantLock specific to each LeaseRequest instance to maintain the original
// synchronization semantics. This ensures that each LeaseRequest has its own unique lock.
Expand All @@ -388,8 +418,15 @@ public ConnectionEndpoint get(
final PoolEntry<HttpRoute, ManagedHttpClientConnection> poolEntry;
try {
poolEntry = leaseFuture.get(timeout.getDuration(), timeout.getTimeUnit());
} catch (final TimeoutException ex) {
resultObtained.set(true);
lateEntryRef.compareAndSet(poolEntry, null);
} catch (final TimeoutException | InterruptedException ex) {
aborted.set(true);
leaseFuture.cancel(true);
final PoolEntry<HttpRoute, ManagedHttpClientConnection> latePoolEntry = lateEntryRef.getAndSet(null);
if (latePoolEntry != null) {
pool.release(latePoolEntry, false);
}
throw ex;
}
if (LOG.isDebugEnabled()) {
Expand Down Expand Up @@ -467,7 +504,18 @@ public ConnectionEndpoint get(

@Override
public boolean cancel() {
return leaseFuture.cancel(true);
lock.lock();
try {
aborted.set(true);
final boolean cancelled = leaseFuture.cancel(true);
final PoolEntry<HttpRoute, ManagedHttpClientConnection> latePoolEntry = lateEntryRef.getAndSet(null);
if (latePoolEntry != null) {
pool.release(latePoolEntry, false);
}
return cancelled;
} finally {
lock.unlock();
}
}

};
Expand Down
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