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// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package main
import (
"flag"
"fmt"
"io/ioutil"
"net/http"
"os"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/simulations"
"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
"github.com/ethereum/go-ethereum/rpc"
)
var adapterType = flag.String("adapter", "sim", `node adapter to use (one of "sim", "exec" or "docker")`)
// main() starts a simulation network which contains nodes running a simple
// ping-pong protocol
func main() {
flag.Parse()
// set the log level to Trace
log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(false))))
// register a single ping-pong service
services := map[string]adapters.ServiceFunc{
"ping-pong": func(ctx *adapters.ServiceContext) (node.Service, error) {
return newPingPongService(ctx.Config.ID), nil
},
}
adapters.RegisterServices(services)
// create the NodeAdapter
var adapter adapters.NodeAdapter
switch *adapterType {
case "sim":
log.Info("using sim adapter")
adapter = adapters.NewSimAdapter(services)
case "exec":
tmpdir, err := ioutil.TempDir("", "p2p-example")
if err != nil {
log.Crit("error creating temp dir", "err", err)
}
defer os.RemoveAll(tmpdir)
log.Info("using exec adapter", "tmpdir", tmpdir)
adapter = adapters.NewExecAdapter(tmpdir)
case "docker":
log.Info("using docker adapter")
var err error
adapter, err = adapters.NewDockerAdapter()
if err != nil {
log.Crit("error creating docker adapter", "err", err)
}
default:
log.Crit(fmt.Sprintf("unknown node adapter %q", *adapterType))
}
// start the HTTP API
log.Info("starting simulation server on 0.0.0.0:8888...")
network := simulations.NewNetwork(adapter, &simulations.NetworkConfig{
DefaultService: "ping-pong",
})
if err := http.ListenAndServe(":8888", simulations.NewServer(network)); err != nil {
log.Crit("error starting simulation server", "err", err)
}
}
// pingPongService runs a ping-pong protocol between nodes where each node
// sends a ping to all its connected peers every 10s and receives a pong in
// return
type pingPongService struct {
id enode.ID
log log.Logger
received int64
}
func newPingPongService(id enode.ID) *pingPongService {
return &pingPongService{
id: id,
log: log.New("node.id", id),
}
}
func (p *pingPongService) Protocols() []p2p.Protocol {
return []p2p.Protocol{{
Name: "ping-pong",
Version: 1,
Length: 2,
Run: p.Run,
NodeInfo: p.Info,
}}
}
func (p *pingPongService) APIs() []rpc.API {
return nil
}
func (p *pingPongService) Start(server *p2p.Server) error {
p.log.Info("ping-pong service starting")
return nil
}
func (p *pingPongService) Stop() error {
p.log.Info("ping-pong service stopping")
return nil
}
func (p *pingPongService) Info() interface{} {
return struct {
Received int64 `json:"received"`
}{
atomic.LoadInt64(&p.received),
}
}
const (
pingMsgCode = iota
pongMsgCode
)
// Run implements the ping-pong protocol which sends ping messages to the peer
// at 10s intervals, and responds to pings with pong messages.
func (p *pingPongService) Run(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
log := p.log.New("peer.id", peer.ID())
errC := make(chan error)
go func() {
for range time.Tick(10 * time.Second) {
log.Info("sending ping")
if err := p2p.Send(rw, pingMsgCode, "PING"); err != nil {
errC <- err
return
}
}
}()
go func() {
for {
msg, err := rw.ReadMsg()
if err != nil {
errC <- err
return
}
payload, err := ioutil.ReadAll(msg.Payload)
if err != nil {
errC <- err
return
}
log.Info("received message", "msg.code", msg.Code, "msg.payload", string(payload))
atomic.AddInt64(&p.received, 1)
if msg.Code == pingMsgCode {
log.Info("sending pong")
go p2p.Send(rw, pongMsgCode, "PONG")
}
}
}()
return <-errC
}
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