Method sendBlockRequests

controller/consensus.go:207–242

Send requests for heights missing in the queue They can be missing because: - Sync has just started and queue isn't full yet - A previous request for a height timed out and was removed from queue - A previous request for a height was removed from the queue for processing Failure in processing leaves

(start, stop uint64, queue map[uint64]blockSyncRequest, limiter *lib.SimpleLimiter, peers []string)

//     Failure in processing leaves that height missing in the queue, triggering another request
//   - Block height has advanced and there's room at the end of the queue
func (c *Controller) sendBlockRequests(start, stop uint64, queue map[uint64]blockSyncRequest, limiter *lib.SimpleLimiter, peers []string) {
	// Send requests to populate the queue
	for height := start; height < stop; height++ {
		// A block request has already been sent for this height
		if _, ok := queue[height]; ok {
			continue
		}
		// Find a random peer that is not rate limited
		allowedPeer := getRandomAllowedPeer(peers, limiter)
		if allowedPeer == "" {
			// All peers rate-limited, cannot send any more requests
			return
		}
		peerPublicKey, _ := lib.StringToBytes(allowedPeer)

		c.log.Debugf("Requesting block for height %d 🔄 from %s", height, lib.BytesToTruncatedString(peerPublicKey))

		// Send block request to selected peer
		err := c.P2P.SendTo(peerPublicKey, BlockRequest, &lib.BlockRequestMessage{
			ChainId:    c.Config.ChainId,
			Height:     height,
			HeightOnly: false,
		})
		if err != nil {
			c.log.Errorf("Error requesting block for height %d 🔄 from %s", height, lib.BytesToTruncatedString(peerPublicKey))
			break
		}

		// Add new request to queue
		queue[height] = blockSyncRequest{
			timestamp:     time.Now(),
			height:        height,
			peerPublicKey: peerPublicKey,
		}
	}
}

// applyTimeouts removes requests from the queue that have timed out
func (c *Controller) applyTimeouts(queue map[uint64]blockSyncRequest) []blockSyncRequest {