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 }