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@popsUlfr
Created June 28, 2021 10:38
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libp2p minimal streams
package main
import (
"bufio"
"context"
"errors"
"fmt"
"io"
"log"
"os"
"os/signal"
"sync"
"syscall"
"time"
"github.com/libp2p/go-libp2p"
connmgr "github.com/libp2p/go-libp2p-connmgr"
"github.com/libp2p/go-libp2p-core/crypto"
"github.com/libp2p/go-libp2p-core/host"
"github.com/libp2p/go-libp2p-core/network"
"github.com/libp2p/go-libp2p-core/peer"
"github.com/libp2p/go-libp2p-core/protocol"
"github.com/libp2p/go-libp2p-core/routing"
discovery "github.com/libp2p/go-libp2p-discovery"
dht "github.com/libp2p/go-libp2p-kad-dht"
libp2pquic "github.com/libp2p/go-libp2p-quic-transport"
)
const RendezvousString = "2d2yzgRJGsOVggRw"
var ProtocolID = protocol.ID(fmt.Sprintf("/%s/1.0.0", RendezvousString))
func handleStream(ctx context.Context, wg *sync.WaitGroup, stream network.Stream) {
ctx, cancel := context.WithCancel(ctx)
rw := bufio.NewReadWriter(bufio.NewReader(stream), bufio.NewWriter(stream))
wg.Add(3)
go func() {
defer wg.Done()
defer stream.Close()
<-ctx.Done()
}()
go func() {
defer wg.Done()
defer cancel()
for {
str, err := rw.ReadString('\n')
if err != nil {
if !errors.Is(err, io.EOF) {
log.Println("Stream read error:", err)
}
return
}
if str == "" {
return
} else if str != "\n" {
log.Println("Stream read:", str)
}
}
}()
go func() {
defer wg.Done()
defer cancel()
for {
_, err := rw.WriteString("hello world\n")
if err != nil {
log.Println("Stream write error:", err)
return
}
err = rw.Flush()
if err != nil {
log.Println("Stream flush error:", err)
return
}
select {
case <-time.After(2 * time.Second):
case <-ctx.Done():
return
}
}
}()
}
func main() {
log.SetFlags(log.LstdFlags | log.Lshortfile)
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
defer stop()
// Generate key pair for identity
priv, _, err := crypto.GenerateKeyPair(crypto.Ed25519, -1)
if err != nil {
log.Println(err)
return
}
bootstrapPeerAddrs := dht.GetDefaultBootstrapPeerAddrInfos()
var dhtIpfs *dht.IpfsDHT
h, err := libp2p.New(ctx,
libp2p.DefaultListenAddrs,
libp2p.DefaultTransports,
libp2p.DefaultMuxers,
libp2p.DefaultSecurity,
libp2p.DefaultPeerstore,
libp2p.DefaultEnableRelay,
libp2p.Identity(priv),
libp2p.ListenAddrStrings(
"/ip4/0.0.0.0/udp/0/quic",
"/ip6/::/udp/0/quic",
),
libp2p.Transport(libp2pquic.NewTransport),
libp2p.DefaultStaticRelays(),
libp2p.EnableAutoRelay(),
libp2p.EnableNATService(),
libp2p.NATPortMap(),
libp2p.ConnectionManager(connmgr.NewConnManager(20, 40, time.Minute)),
libp2p.Routing(func(h host.Host) (routing.PeerRouting, error) {
var err error
dhtIpfs, err = dht.New(ctx, h,
dht.Mode(dht.ModeServer),
dht.BootstrapPeers(bootstrapPeerAddrs...))
return dhtIpfs, err
}))
if err != nil {
log.Println(err)
return
}
defer h.Close()
log.Println("Host ID:", h.ID())
log.Println("ListenAddresses:", h.Network().ListenAddresses())
var wg sync.WaitGroup
h.SetStreamHandler(ProtocolID, func(s network.Stream) {
handleStream(ctx, &wg, s)
})
err = dhtIpfs.Bootstrap(ctx)
if err != nil {
log.Println(err)
return
}
for _, peerAddr := range bootstrapPeerAddrs {
wg.Add(1)
go func(peerAddr peer.AddrInfo) {
defer wg.Done()
err := h.Connect(ctx, peerAddr)
if err != nil {
log.Println("Bootstrap connect error:", err, peerAddr)
} else {
log.Println("Bootstrap connect:", peerAddr)
}
}(peerAddr)
}
wg.Wait()
routingDiscovery := discovery.NewRoutingDiscovery(dhtIpfs)
log.Println("Advertising and finding peers...")
wg.Add(1)
go func() {
defer wg.Done()
for ctx.Err() == nil {
_, err := routingDiscovery.Advertise(ctx, RendezvousString)
if err != nil {
if !errors.Is(err, context.DeadlineExceeded) {
log.Println(err)
return
} else {
log.Println("Advertise failed retrying...")
}
} else {
break
}
}
// see limit option
peerAddrsChan, err := routingDiscovery.FindPeers(ctx, RendezvousString)
if err != nil {
log.Println(err)
return
}
for {
select {
case peerAddr := <-peerAddrsChan:
// most of the peers are empty!
if (len(peerAddr.Addrs) == 0 && peerAddr.ID == "") || peerAddr.ID == h.ID() {
continue
}
stream, err := h.NewStream(ctx, peerAddr.ID, ProtocolID)
if err != nil {
log.Println("Stream error:", err, peerAddr)
} else {
log.Println("Stream opened:", peerAddr)
handleStream(ctx, &wg, stream)
}
case <-ctx.Done():
return
}
}
}()
wg.Wait()
}
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