Source: writesched_random.go in package golang.org/x/net/http2

Source File
	writesched_random.go

Belonging Package
	golang.org/x/net/http2


package http2

import "math"

NewRandomWriteScheduler constructs a WriteScheduler that ignores HTTP/2 priorities. Control frames like SETTINGS and PING are written before DATA frames, but if no control frames are queued and multiple streams have queued HEADERS or DATA frames, Pop selects a ready stream arbitrarily.

func NewRandomWriteScheduler() WriteScheduler {
	return &randomWriteScheduler{sq: make(map[uint32]*writeQueue)}
}

zero are frames not associated with a specific stream.

	zero writeQueue

sq contains the stream-specific queues, keyed by stream ID. When a stream is idle, closed, or emptied, it's deleted from the map.

	sq map[uint32]*writeQueue

pool of empty queues for reuse.

	queuePool writeQueuePool
}

no-op: idle streams are not tracked

}

func (ws *randomWriteScheduler) CloseStream(streamID uint32) {
	q, ok := ws.sq[streamID]
	if !ok {
		return
	}
	delete(ws.sq, streamID)
	ws.queuePool.put(q)
}

no-op: priorities are ignored

}

func (ws *randomWriteScheduler) Push(wr FrameWriteRequest) {
	id := wr.StreamID()
	if id == 0 {
		ws.zero.push(wr)
		return
	}
	q, ok := ws.sq[id]
	if !ok {
		q = ws.queuePool.get()
		ws.sq[id] = q
	}
	q.push(wr)
}

Control frames first.

	if !ws.zero.empty() {
		return ws.zero.shift(), true

Iterate over all non-idle streams until finding one that can be consumed.

	for streamID, q := range ws.sq {
		if wr, ok := q.consume(math.MaxInt32); ok {
			if q.empty() {
				delete(ws.sq, streamID)
				ws.queuePool.put(q)
			}
			return wr, true
		}
	}
	return FrameWriteRequest{}, false


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