lotus/lib/addrutil/parse.go

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package addrutil
import (
"context"
"fmt"
"sync"
"time"
"github.com/libp2p/go-libp2p-core/peer"
ma "github.com/multiformats/go-multiaddr"
madns "github.com/multiformats/go-multiaddr-dns"
)
// ParseAddresses is a function that takes in a slice of string peer addresses
// (multiaddr + peerid) and returns a slice of properly constructed peers
func ParseAddresses(ctx context.Context, addrs []string) ([]peer.AddrInfo, error) {
// resolve addresses
maddrs, err := resolveAddresses(ctx, addrs)
if err != nil {
return nil, err
}
return peer.AddrInfosFromP2pAddrs(maddrs...)
}
const (
dnsResolveTimeout = 10 * time.Second
)
// resolveAddresses resolves addresses parallelly
func resolveAddresses(ctx context.Context, addrs []string) ([]ma.Multiaddr, error) {
ctx, cancel := context.WithTimeout(ctx, dnsResolveTimeout)
defer cancel()
var maddrs []ma.Multiaddr
var wg sync.WaitGroup
resolveErrC := make(chan error, len(addrs))
maddrC := make(chan ma.Multiaddr)
for _, addr := range addrs {
maddr, err := ma.NewMultiaddr(addr)
if err != nil {
return nil, err
}
// check whether address ends in `ipfs/Qm...`
if _, last := ma.SplitLast(maddr); last.Protocol().Code == ma.P_IPFS {
maddrs = append(maddrs, maddr)
continue
}
wg.Add(1)
go func(maddr ma.Multiaddr) {
defer wg.Done()
raddrs, err := madns.Resolve(ctx, maddr)
if err != nil {
resolveErrC <- err
return
}
// filter out addresses that still doesn't end in `ipfs/Qm...`
found := 0
for _, raddr := range raddrs {
if _, last := ma.SplitLast(raddr); last != nil && last.Protocol().Code == ma.P_IPFS {
maddrC <- raddr
found++
}
}
if found == 0 {
resolveErrC <- fmt.Errorf("found no ipfs peers at %s", maddr)
}
}(maddr)
}
go func() {
wg.Wait()
close(maddrC)
}()
for maddr := range maddrC {
maddrs = append(maddrs, maddr)
}
select {
case err := <-resolveErrC:
return nil, err
default:
}
return maddrs, nil
}