Get NEO node connected peer state info

peer-state.go

package main

import (
	"context"
	"fmt"
	"github.com/nspcc-dev/neo-go/pkg/io"
	"github.com/nspcc-dev/neo-go/pkg/network"
	"github.com/nspcc-dev/neo-go/pkg/network/capability"
	"github.com/nspcc-dev/neo-go/pkg/network/payload"
	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
	"log"
	"net"
	"sync"
	"time"
)

func main() {
	opts := rpcclient.Options{}
	c, err := rpcclient.New(context.TODO(), os.Args[1], opts)
	if err != nil {
		log.Fatalf("faild to create new RPC client: %v", err)
	}
	err = c.Init()
	if err != nil {
		log.Fatalf("failed to initialise RPC client: %v", err)
	}

	peers, err := c.GetPeers()
	if err != nil {
		return
	}

	var wg sync.WaitGroup
	for _, p := range peers.Connected {
		addr := fmt.Sprintf("%s:%d", p.Address, p.Port)
		wg.Add(1)
		go collectAndPrint(addr, &wg)
	}
	wg.Wait()
}

func collectAndPrint(addr string, wg *sync.WaitGroup) {
	defer wg.Done()
	conn, err := net.DialTimeout("tcp", addr, 3*time.Second)
	if err != nil {
		//log.Printf("failed to connect to peer %q: %v", addr, err)
		return
	}
	r := io.NewBinReaderFromIO(conn)
	m := network.Message{}
	err = m.Decode(r)
	if err != nil {
		return
	}
	if p, ok := m.Payload.(*payload.Version); ok {
		for _, c := range p.Capabilities {
			if c.Type == capability.FullNode {
				height := c.Data.(*capability.Node).StartHeight
				fmt.Printf("%22s - %7d - %s\n", addr, height, p.UserAgent)
				break
			}
		}
	}
}