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Add configurable HTTP/2 connection window size #663

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35 changes: 33 additions & 2 deletions httpcore5-h2/src/main/java/org/apache/hc/core5/http2/config/H2Config.java
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Original file line number Diff line number Diff line change
Expand Up @@ -47,19 +47,21 @@ public class H2Config {
private final boolean pushEnabled;
private final int maxConcurrentStreams;
private final int initialWindowSize;
private final int connectionWindowSize;
private final int maxFrameSize;
private final int maxHeaderListSize;
private final boolean compressionEnabled;
private final int maxContinuations;

H2Config(final int headerTableSize, final boolean pushEnabled, final int maxConcurrentStreams,
final int initialWindowSize, final int maxFrameSize, final int maxHeaderListSize,
final boolean compressionEnabled, final int maxContinuations) {
final int initialWindowSize, final int connectionWindowSize, final int maxFrameSize,
final int maxHeaderListSize, final boolean compressionEnabled, final int maxContinuations) {
super();
this.headerTableSize = headerTableSize;
this.pushEnabled = pushEnabled;
this.maxConcurrentStreams = maxConcurrentStreams;
this.initialWindowSize = initialWindowSize;
this.connectionWindowSize = connectionWindowSize;
this.maxFrameSize = maxFrameSize;
this.maxHeaderListSize = maxHeaderListSize;
this.compressionEnabled = compressionEnabled;
Expand All @@ -82,6 +84,16 @@ public int getInitialWindowSize() {
return initialWindowSize;
}

/**
* Returns the connection-level receive window size. This controls the flow-control
* window for the entire connection as opposed to individual streams.
*
* @since 5.5
*/
public int getConnectionWindowSize() {
return connectionWindowSize;
}

public int getMaxFrameSize() {
return maxFrameSize;
}
Expand All @@ -105,6 +117,7 @@ public String toString() {
.append(", pushEnabled=").append(this.pushEnabled)
.append(", maxConcurrentStreams=").append(this.maxConcurrentStreams)
.append(", initialWindowSize=").append(this.initialWindowSize)
.append(", connectionWindowSize=").append(this.connectionWindowSize)
.append(", maxFrameSize=").append(this.maxFrameSize)
.append(", maxHeaderListSize=").append(this.maxHeaderListSize)
.append(", compressionEnabled=").append(this.compressionEnabled)
Expand All @@ -130,6 +143,7 @@ public static H2Config.Builder initial() {
.setMaxConcurrentStreams(Integer.MAX_VALUE) // no limit
.setMaxFrameSize(INIT_MAX_FRAME_SIZE)
.setInitialWindowSize(INIT_WINDOW_SIZE)
.setConnectionWindowSize(INIT_WINDOW_SIZE)
.setMaxHeaderListSize(Integer.MAX_VALUE); // unlimited
}

Expand All @@ -140,6 +154,7 @@ public static H2Config.Builder copy(final H2Config config) {
.setPushEnabled(config.isPushEnabled())
.setMaxConcurrentStreams(config.getMaxConcurrentStreams())
.setInitialWindowSize(config.getInitialWindowSize())
.setConnectionWindowSize(config.getConnectionWindowSize())
.setMaxFrameSize(config.getMaxFrameSize())
.setMaxHeaderListSize(config.getMaxHeaderListSize())
.setCompressionEnabled(config.isCompressionEnabled());
Expand All @@ -151,6 +166,7 @@ public static class Builder {
private boolean pushEnabled;
private int maxConcurrentStreams;
private int initialWindowSize;
private int connectionWindowSize;
private int maxFrameSize;
private int maxHeaderListSize;
private boolean compressionEnabled;
Expand All @@ -161,6 +177,7 @@ public static class Builder {
this.pushEnabled = INIT_ENABLE_PUSH;
this.maxConcurrentStreams = INIT_CONCURRENT_STREAM;
this.initialWindowSize = INIT_WINDOW_SIZE;
this.connectionWindowSize = Integer.MAX_VALUE;
this.maxFrameSize = FrameConsts.MIN_FRAME_SIZE * 4;
this.maxHeaderListSize = FrameConsts.MAX_FRAME_SIZE;
this.compressionEnabled = true;
Expand Down Expand Up @@ -188,6 +205,19 @@ public Builder setInitialWindowSize(final int initialWindowSize) {
return this;
}

/**
* Sets the connection-level receive window size. This controls the flow-control
* window for the entire connection as opposed to individual streams governed by
* {@link #setInitialWindowSize(int)}.
*
* @since 5.5
*/
public Builder setConnectionWindowSize(final int connectionWindowSize) {
this.connectionWindowSize = Args.checkRange(connectionWindowSize, INIT_WINDOW_SIZE,
Integer.MAX_VALUE, "Connection window size");
return this;
}

public Builder setMaxFrameSize(final int maxFrameSize) {
this.maxFrameSize = Args.checkRange(maxFrameSize, FrameConsts.MIN_FRAME_SIZE, FrameConsts.MAX_FRAME_SIZE,
"Invalid max frame size");
Expand Down Expand Up @@ -222,6 +252,7 @@ public H2Config build() {
pushEnabled,
maxConcurrentStreams,
initialWindowSize,
connectionWindowSize,
maxFrameSize,
maxHeaderListSize,
compressionEnabled,
Expand Down
33 changes: 23 additions & 10 deletions ...ore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -104,7 +104,7 @@

abstract class AbstractH2StreamMultiplexer implements Identifiable, HttpConnection {

private static final long CONNECTION_WINDOW_LOW_MARK = 10 * 1024 * 1024;
private static final int DEFAULT_CONNECTION_WINDOW_LOW_MARK = 10 * 1024 * 1024;

enum ConnectionHandshake { READY, ACTIVE, GRACEFUL_SHUTDOWN, SHUTDOWN }
enum SettingsHandshake { READY, TRANSMITTED, ACKED }
Expand Down Expand Up @@ -132,6 +132,8 @@ enum SettingsHandshake { READY, TRANSMITTED, ACKED }
private SettingsHandshake localSettingState = SettingsHandshake.READY;
private SettingsHandshake remoteSettingState = SettingsHandshake.READY;

private final int connWindowSize;
private final long connWindowLowMark;
private int initInputWinSize;
private int initOutputWinSize;
private int lowMark;
Expand Down Expand Up @@ -178,6 +180,10 @@ enum SettingsHandshake { READY, TRANSMITTED, ACKED }
this.httpProcessor = Args.notNull(httpProcessor, "HTTP processor");
this.streams = new H2Streams(idGenerator);
this.localConfig = h2Config != null ? h2Config : H2Config.DEFAULT;
this.connWindowSize = this.localConfig.getConnectionWindowSize();
this.connWindowLowMark = this.connWindowSize == Integer.MAX_VALUE
? DEFAULT_CONNECTION_WINDOW_LOW_MARK
: this.connWindowSize / 2;
this.inputMetrics = new BasicH2TransportMetrics();
this.outputMetrics = new BasicH2TransportMetrics();
this.connMetrics = new BasicHttpConnectionMetrics(this.inputMetrics, this.outputMetrics);
Expand Down Expand Up @@ -258,11 +264,15 @@ private int updateWindow(final AtomicInteger window, final int delta) throws Ari
}
}

private int updateWindowMax(final AtomicInteger window) throws ArithmeticException {
private int updateWindowTo(final AtomicInteger window, final int target) throws ArithmeticException {
for (;;) {
final int current = window.get();
if (window.compareAndSet(current, Integer.MAX_VALUE)) {
return Integer.MAX_VALUE - current;
final int delta = target - current;
if (delta <= 0) {
return 0;
}
if (window.compareAndSet(current, target)) {
return delta;
}
}
}
Expand Down Expand Up @@ -446,7 +456,7 @@ public final void onConnect() throws HttpException, IOException {

commitFrame(settingsFrame);
localSettingState = SettingsHandshake.TRANSMITTED;
maximizeWindow(0, connInputWindow);
replenishWindow(0, connInputWindow, connWindowSize);

if (streamListener != null) {
final int initInputWindow = connInputWindow.get();
Expand Down Expand Up @@ -1119,15 +1129,15 @@ private void consumeDataFrame(final RawFrame frame, final H2Stream stream) throw
stream.produceInputCapacityUpdate();
}
final int connWinSize = updateInputWindow(0, connInputWindow, -frameLength);
if (connWinSize < CONNECTION_WINDOW_LOW_MARK) {
maximizeWindow(0, connInputWindow);
if (connWinSize < connWindowLowMark) {
replenishWindow(0, connInputWindow, connWindowSize);
}
}
stream.consumeData(payload, frame.isFlagSet(FrameFlag.END_STREAM));
}

private void maximizeWindow(final int streamId, final AtomicInteger window) throws IOException {
final int delta = updateWindowMax(window);
private void replenishWindow(final int streamId, final AtomicInteger window, final int target) throws IOException {
final int delta = updateWindowTo(window, target);
if (delta > 0) {
final RawFrame windowUpdateFrame = frameFactory.createWindowUpdate(streamId, delta);
commitFrame(windowUpdateFrame);
Expand Down Expand Up @@ -1594,7 +1604,10 @@ public void push(final List<Header> headers, final AsyncPushProducer pushProduce

@Override
public void update(final int increment) throws IOException {
incrementInputCapacity(0, connInputWindow, increment);
final int connCeiling = connWindowSize - connInputWindow.get();
if (connCeiling > 0) {
incrementInputCapacity(0, connInputWindow, Math.min(increment, connCeiling));
}
incrementInputCapacity(id, inputWindow, increment);
}

Expand Down
18 changes: 12 additions & 6 deletions httpcore5-h2/src/test/java/org/apache/hc/core5/http2/config/H2ConfigTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -37,28 +37,32 @@
class H2ConfigTest {

@Test
void builder() {
// Create and start requester
final H2Config h2Config = H2Config.custom()
.setPushEnabled(false)
.build();
void defaults() {
final H2Config h2Config = H2Config.custom().build();
assertNotNull(h2Config);
assertEquals(65535, h2Config.getInitialWindowSize());
assertEquals(Integer.MAX_VALUE, h2Config.getConnectionWindowSize());
}

@Test
void checkValues() {
// Create and start requester
final H2Config h2Config = H2Config.custom()
.setHeaderTableSize(1)
.setMaxConcurrentStreams(1)
.setInitialWindowSize(131072)
.setConnectionWindowSize(1048576)
.setMaxFrameSize(16384)
.setMaxHeaderListSize(4096)
.setPushEnabled(true)
.setCompressionEnabled(true)
.build();

assertEquals(1, h2Config.getHeaderTableSize());
assertEquals(1, h2Config.getMaxConcurrentStreams());
assertEquals(131072, h2Config.getInitialWindowSize());
assertEquals(1048576, h2Config.getConnectionWindowSize());
assertEquals(16384, h2Config.getMaxFrameSize());
assertEquals(4096, h2Config.getMaxHeaderListSize());
assertTrue(h2Config.isPushEnabled());
assertTrue(h2Config.isCompressionEnabled());
}
Expand All @@ -70,6 +74,7 @@ void copy() {
.setHeaderTableSize(1)
.setMaxConcurrentStreams(1)
.setMaxFrameSize(16384)
.setConnectionWindowSize(2097152)
.setPushEnabled(true)
.setCompressionEnabled(true)
.build();
Expand All @@ -80,6 +85,7 @@ void copy() {
assertAll(
() -> assertEquals(h2Config.getHeaderTableSize(), h2Config2.getHeaderTableSize()),
() -> assertEquals(h2Config.getInitialWindowSize(), h2Config2.getInitialWindowSize()),
() -> assertEquals(h2Config.getConnectionWindowSize(), h2Config2.getConnectionWindowSize()),
() -> assertEquals(h2Config.getMaxConcurrentStreams(), h2Config2.getMaxConcurrentStreams()),
() -> assertEquals(h2Config.getMaxFrameSize(), h2Config2.getMaxFrameSize()),
() -> assertEquals(h2Config.getMaxHeaderListSize(), h2Config2.getMaxHeaderListSize())
Expand Down
128 changes: 128 additions & 0 deletions ...-h2/src/test/java/org/apache/hc/core5/http2/impl/nio/TestAbstractH2StreamMultiplexer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.Lock;
import java.util.stream.IntStream;

Expand Down Expand Up @@ -2017,5 +2018,132 @@ void testHeadersWithPrioritySelfDependencyIsStreamProtocolError() throws Excepti
.consumeHeader(ArgumentMatchers.anyList(), ArgumentMatchers.anyBoolean());
}

@Test
void testConnectionWindowSizeOnConnect() throws Exception {
final int configuredWindowSize = 1048576; // 1 MB
final List<byte[]> writes = new ArrayList<>();
Mockito.when(protocolIOSession.write(ArgumentMatchers.any(ByteBuffer.class)))
.thenAnswer(inv -> {
final ByteBuffer b = inv.getArgument(0, ByteBuffer.class);
final byte[] copy = new byte[b.remaining()];
b.get(copy);
writes.add(copy);
return copy.length;
});
Mockito.doNothing().when(protocolIOSession).setEvent(ArgumentMatchers.anyInt());
Mockito.doNothing().when(protocolIOSession).clearEvent(ArgumentMatchers.anyInt());

final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
protocolIOSession, FRAME_FACTORY, StreamIdGenerator.ODD,
httpProcessor, CharCodingConfig.DEFAULT,
H2Config.custom()
.setConnectionWindowSize(configuredWindowSize)
.build(),
h2StreamListener, () -> streamHandler);

mux.onConnect();

final List<FrameStub> frames = parseFrames(concat(writes));
final int expectedDelta = configuredWindowSize - 65535;
final boolean found = frames.stream().anyMatch(f ->
f.type == FrameType.WINDOW_UPDATE.getValue()
&& f.streamId == 0
&& f.payload.length == 4
&& ((f.payload[0] & 0xff) << 24
| (f.payload[1] & 0xff) << 16
| (f.payload[2] & 0xff) << 8
| (f.payload[3] & 0xff)) == expectedDelta);
Assertions.assertTrue(found,
"onConnect must send WINDOW_UPDATE(stream=0, delta=" + expectedDelta + ")");

final Field connInputWindowField =
AbstractH2StreamMultiplexer.class.getDeclaredField("connInputWindow");
connInputWindowField.setAccessible(true);
final AtomicInteger connInputWindow = (AtomicInteger) connInputWindowField.get(mux);
Assertions.assertEquals(configuredWindowSize, connInputWindow.get());
}

@Test
void testDefaultConnectionWindowSizeMaximizesOnConnect() throws Exception {
final List<byte[]> writes = new ArrayList<>();
Mockito.when(protocolIOSession.write(ArgumentMatchers.any(ByteBuffer.class)))
.thenAnswer(inv -> {
final ByteBuffer b = inv.getArgument(0, ByteBuffer.class);
final byte[] copy = new byte[b.remaining()];
b.get(copy);
writes.add(copy);
return copy.length;
});
Mockito.doNothing().when(protocolIOSession).setEvent(ArgumentMatchers.anyInt());
Mockito.doNothing().when(protocolIOSession).clearEvent(ArgumentMatchers.anyInt());

final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
protocolIOSession, FRAME_FACTORY, StreamIdGenerator.ODD,
httpProcessor, CharCodingConfig.DEFAULT, H2Config.DEFAULT,
h2StreamListener, () -> streamHandler);

mux.onConnect();

final Field connInputWindowField =
AbstractH2StreamMultiplexer.class.getDeclaredField("connInputWindow");
connInputWindowField.setAccessible(true);
final AtomicInteger connInputWindow = (AtomicInteger) connInputWindowField.get(mux);
Assertions.assertEquals(Integer.MAX_VALUE, connInputWindow.get(),
"Default config must maximize connection input window");
}

@Test
void testConnectionWindowSizeDoesNotAffectSettingsInitialWindowSize() throws Exception {
final int streamWindowSize = 32768;
final int connWindowSize = 1048576;
final List<byte[]> writes = new ArrayList<>();
Mockito.when(protocolIOSession.write(ArgumentMatchers.any(ByteBuffer.class)))
.thenAnswer(inv -> {
final ByteBuffer b = inv.getArgument(0, ByteBuffer.class);
final byte[] copy = new byte[b.remaining()];
b.get(copy);
writes.add(copy);
return copy.length;
});
Mockito.doNothing().when(protocolIOSession).setEvent(ArgumentMatchers.anyInt());
Mockito.doNothing().when(protocolIOSession).clearEvent(ArgumentMatchers.anyInt());

final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
protocolIOSession, FRAME_FACTORY, StreamIdGenerator.ODD,
httpProcessor, CharCodingConfig.DEFAULT,
H2Config.custom()
.setInitialWindowSize(streamWindowSize)
.setConnectionWindowSize(connWindowSize)
.build(),
h2StreamListener, () -> streamHandler);

mux.onConnect();

final List<FrameStub> frames = parseFrames(concat(writes));
final FrameStub settingsFrame = frames.stream()
.filter(f -> f.type == FrameType.SETTINGS.getValue()
&& f.streamId == 0
&& !f.isAck())
.findFirst()
.orElseThrow(() -> new AssertionError("No SETTINGS frame found"));

final int initialWindowSizeParamCode = 0x4;
int advertisedWindowSize = -1;
for (int i = 0; i + 5 < settingsFrame.payload.length; i += 6) {
final int id = ((settingsFrame.payload[i] & 0xff) << 8)
| (settingsFrame.payload[i + 1] & 0xff);
final int val = ((settingsFrame.payload[i + 2] & 0xff) << 24)
| ((settingsFrame.payload[i + 3] & 0xff) << 16)
| ((settingsFrame.payload[i + 4] & 0xff) << 8)
| (settingsFrame.payload[i + 5] & 0xff);
if (id == initialWindowSizeParamCode) {
advertisedWindowSize = val;
}
}

Assertions.assertEquals(streamWindowSize, advertisedWindowSize,
"SETTINGS INITIAL_WINDOW_SIZE must reflect initialWindowSize, not connectionWindowSize");
}


}
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