Package reactor.netty.http

Class Http2ConnectionLiveness

java.lang.Object

reactor.netty.http.Http2ConnectionLiveness

All Implemented Interfaces:

HttpConnectionLiveness

public final class Http2ConnectionLiveness
extends Object
implements HttpConnectionLiveness

Supports connection health checks using HTTP/2 PING frames.

This class implements liveness detection for HTTP/2 connections by sending PING frames when the connection becomes idle (no read/write activity). The peer must respond with a PING ACK within the configured timeout, otherwise the connection is considered unresponsive.

Behavior

• PING frames are only sent when the connection is idle (no active reads/writes)
• Each PING frame must receive an ACK within pingAckTimeout
• If no ACK is received, retry up to pingAckDropThreshold times
• If all attempts fail, the connection is closed
• Receiving any HTTP/2 frame (HEADERS, DATA, or PING ACK) cancels the health check

Thread Safety

This class is designed to be used with a single channel. All operations, including scheduled tasks, execute on the channel's event loop thread, eliminating the need for explicit synchronization. A new instance is created per channel.

Configuration Guidelines

• pingAckTimeout: Should account for expected network latency and load. Values that are too short may cause false positives due to temporary delays.
• pingAckDropThreshold: Balance between quick failure detection and tolerance for transient issues. Higher values increase detection time but reduce false positives.

Since:

1.2.12

Author:

raccoonback, Violeta Georgieva

Field Summary

Fields inherited from interface reactor.netty.http.HttpConnectionLiveness

CLOSE, log

Constructor Summary

Constructors

Constructor	Description
Http2ConnectionLiveness(Http2FrameCodec http2FrameCodec, int pingAckDropThreshold, long pingAckTimeoutNanos)	Constructs a new Http2ConnectionLiveness instance.

Method Summary

Modifier and Type	Method	Description
void	cancel()	Cancels the scheduled ping task.
void	check(ChannelHandlerContext ctx)	Checks the liveness of the connection and schedules a ping if necessary.
void	receive(Object msg)	Receives a message from the peer and processes it if it is a ping frame.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Http2ConnectionLiveness

public Http2ConnectionLiveness(Http2FrameCodec http2FrameCodec,
 int pingAckDropThreshold,
 long pingAckTimeoutNanos)

Constructs a new Http2ConnectionLiveness instance.

Parameters:

http2FrameCodec - the HTTP/2 frame codec

pingAckDropThreshold - the maximum number of PING frame transmission attempts before closing the connection

pingAckTimeoutNanos - the timeout in nanoseconds for receiving a PING ACK response

Method Details

cancel

public void cancel()

Cancels the scheduled ping task.

Specified by:

cancel in interface HttpConnectionLiveness

check

public void check(ChannelHandlerContext ctx)

Checks the liveness of the connection and schedules a ping if necessary.

Specified by:

check in interface HttpConnectionLiveness

Parameters:

ctx - the ChannelHandlerContext of the connection

receive

public void receive(Object msg)

Receives a message from the peer and processes it if it is a ping frame.

Specified by:

receive in interface HttpConnectionLiveness

Parameters:

msg - the message received from the peer