x/net/http2: configurable server pings

[neild]

This issue is part of a project to move x/net/http2 into std: #67810

A HTTP/2 client or server may send PING frames to its peer. (RFC 9113 Section 6.7)

The http2.ReadIdleTimeout and http2.PingTimeout fields configure an HTTP/2 client to send a PING when a connection has been idle for some amount of time, and to close the connection if no response is received.

The http2.Server does not support sending PINGs on idle connections.

I propose adding the ability to configure servers to send pings as well. This setting will be off by default.

package http2

type Server struct { // contains unchanged fields
	// ReadIdleTimeout is the timeout after which a health check using a ping
	// frame will be carried out if no frame is received on a connection.
	// If zero, no health check is performed.
	ReadIdleTimeout time.Duration

	// PingTimeout is the timeout after which a connection will be closed
	// if a response to a ping is not received.
	// If zero, a default of 15 seconds is used.
	PingTimeout time.Duration
}

---

Adding this feature removes an inconsistency between HTTP/2 client and server configurations. Aligning the two will make it easier to add support for configuring HTTP/2 features to net/http, since we can define a single configuration struct rather than separate ones for clients and servers.

[rsc]

This proposal has been added to the active column of the proposals project
and will now be reviewed at the weekly proposal review meetings.
— rsc for the proposal review group

[rsc]

Have all remaining concerns about this proposal been addressed?

The proposal is to add two new fields to http2.Server:

	// ReadIdleTimeout is the timeout after which a health check using a ping
	// frame will be carried out if no frame is received on a connection.
	// If zero, no health check is performed.
	ReadIdleTimeout time.Duration

	// PingTimeout is the timeout after which a connection will be closed
	// if a response to a ping is not received.
	// If zero, a default of 15 seconds is used.
	PingTimeout time.Duration

[rsc]

Based on the discussion above, this proposal seems like a likely accept.
— rsc for the proposal review group

The proposal is to add two new fields to http2.Server:

	// ReadIdleTimeout is the timeout after which a health check using a ping
	// frame will be carried out if no frame is received on a connection.
	// If zero, no health check is performed.
	ReadIdleTimeout time.Duration

	// PingTimeout is the timeout after which a connection will be closed
	// if a response to a ping is not received.
	// If zero, a default of 15 seconds is used.
	PingTimeout time.Duration

[rsc]

No change in consensus, so accepted. 🎉
This issue now tracks the work of implementing the proposal.
— rsc for the proposal review group

The proposal is to add two new fields to http2.Server:

	// ReadIdleTimeout is the timeout after which a health check using a ping
	// frame will be carried out if no frame is received on a connection.
	// If zero, no health check is performed.
	ReadIdleTimeout time.Duration

	// PingTimeout is the timeout after which a connection will be closed
	// if a response to a ping is not received.
	// If zero, a default of 15 seconds is used.
	PingTimeout time.Duration