Request blob sidecar from beacon node

main.go

package main

import (
	"context"
	"fmt"
	libp2pcore "github.com/libp2p/go-libp2p-core"
	"github.com/libp2p/go-libp2p-core/peer"
	"github.com/pkg/errors"
	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
	"github.com/prysmaticlabs/prysm/beacon-chain/sync"
	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
	"io"
)

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	req := &ethpb.BlobsSidecarsByRangeRequest{
		StartSlot: 10,
		Count:     10,
	}

	svc, err := p2p.NewService(ctx, &p2p.Config{})
	if err != nil {
		panic(err)
	}

	addr, err := peer.AddrInfoFromString("/ip4/192.168.86.249/tcp/13000/p2p/16Uiu2HAmD5XwkprYDfmgunmafiH58ZfY3n56Dr41ahydoCmh23Kt")
	if err != nil {
		panic(err)
	}

	err = svc.Connect(*addr)
	if err != nil {
		panic(err)
	}

	sidecars, err := SendBlobsSidecarsByRangeRequest(ctx, svc, addr.ID, req)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Got %d sidecars: %+v\n", len(sidecars), sidecars)
}

func SendBlobsSidecarsByRangeRequest(
	ctx context.Context, p2pProvider p2p.P2P, pid peer.ID, req *ethpb.BlobsSidecarsByRangeRequest) ([]*ethpb.BlobsSidecar, error) {
	stream, err := p2pProvider.Send(ctx, req, p2p.RPCBlobsSidecarsByRangeTopicV1, pid)
	if err != nil {
		return nil, err
	}
	defer func() {
		_ = stream.Close()
	}()

	var blobsSidecars []*ethpb.BlobsSidecar
	for {
		blobs, err := ReadChunkedBlobsSidecar(stream, p2pProvider)
		if errors.Is(err, io.EOF) {
			break
		}
		if err != nil {
			return nil, err
		}

		blobsSidecars = append(blobsSidecars, blobs)
	}
	return blobsSidecars, nil
}

func ReadChunkedBlobsSidecar(stream libp2pcore.Stream, p2p p2p.P2P) (*ethpb.BlobsSidecar, error) {
	code, errMsg, err := sync.ReadStatusCode(stream, p2p.Encoding())
	if err != nil {
		return nil, err
	}
	if code != 0 {
		return nil, errors.New(errMsg)
	}
	sidecar := new(ethpb.BlobsSidecar)
	err = p2p.Encoding().DecodeWithMaxLength(stream, sidecar)
	return sidecar, err
}