make DNS resolver pluggable, use new madns.BasicResolver interface

dns.go

@@ -11,13 +11,14 @@ import (
 	path "github.com/ipfs/go-path"
 	opts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
 	isd "github.com/jbenet/go-is-domain"
+	madns "github.com/multiformats/go-multiaddr-dns"
 )
 
 const ethTLD = "eth"
 const linkTLD = "domains"
 
 // LookupTXTFunc is a generic type for a function that lookups TXT record values.
-type LookupTXTFunc func(name string) (txt []string, err error)
+type LookupTXTFunc func(ctx context.Context, name string) (txt []string, err error)
 
 // DNSResolver implements a Resolver on DNS domains
 type DNSResolver struct {
@@ -27,8 +28,8 @@ type DNSResolver struct {
 }
 
 // NewDNSResolver constructs a name resolver using DNS TXT records.
-func NewDNSResolver() *DNSResolver {
-	return &DNSResolver{lookupTXT: net.LookupTXT}
+func NewDNSResolver(rslv madns.BasicResolver) *DNSResolver {
+	return &DNSResolver{lookupTXT: rslv.LookupTXT}
 }
 
 // Resolve implements Resolver.
@@ -75,10 +76,10 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 	}
 
 	rootChan := make(chan lookupRes, 1)
-	go workDomain(r, fqdn, rootChan)
+	go workDomain(ctx, r, fqdn, rootChan)
 
 	subChan := make(chan lookupRes, 1)
-	go workDomain(r, "_dnslink."+fqdn, subChan)
+	go workDomain(ctx, r, "_dnslink."+fqdn, subChan)
 
 	appendPath := func(p path.Path) (path.Path, error) {
 		if len(segments) > 1 {
@@ -139,10 +140,10 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 	return out
 }
 
-func workDomain(r *DNSResolver, name string, res chan lookupRes) {
+func workDomain(ctx context.Context, r *DNSResolver, name string, res chan lookupRes) {
 	defer close(res)
 
-	txt, err := r.lookupTXT(name)
+	txt, err := r.lookupTXT(ctx, name)
 	if err != nil {
 		if dnsErr, ok := err.(*net.DNSError); ok {
 			// If no TXT records found, return same error as when no text

dns_test.go

 package namesys
 
 import (
+	"context"
 	"fmt"
 	"testing"
 
@@ -11,7 +12,7 @@ type mockDNS struct {
 	entries map[string][]string
 }
 
-func (m *mockDNS) lookupTXT(name string) (txt []string, err error) {
+func (m *mockDNS) lookupTXT(ctx context.Context, name string) (txt []string, err error) {
 	txt, ok := m.entries[name]
 	if !ok {
 		return nil, fmt.Errorf("no TXT entry for %s", name)

go.mod

@@ -22,6 +22,7 @@ require (
 	github.com/libp2p/go-libp2p-record v0.1.3
 	github.com/libp2p/go-libp2p-testing v0.4.0
 	github.com/multiformats/go-multiaddr v0.3.1
+	github.com/multiformats/go-multiaddr-dns v0.3.0
 	github.com/multiformats/go-multihash v0.0.14
 	github.com/whyrusleeping/base32 v0.0.0-20170828182744-c30ac30633cc
 )

namesys.go

@@ -29,6 +29,7 @@ import (
 	ci "github.com/libp2p/go-libp2p-core/crypto"
 	peer "github.com/libp2p/go-libp2p-core/peer"
 	routing "github.com/libp2p/go-libp2p-core/routing"
+	madns "github.com/multiformats/go-multiaddr-dns"
 )
 
 // mpns (a multi-protocol NameSystem) implements generic IPFS naming.
@@ -49,7 +50,7 @@ type mpns struct {
 }
 
 // NewNameSystem will construct the IPFS naming system based on Routing
-func NewNameSystem(r routing.ValueStore, ds ds.Datastore, cachesize int) NameSystem {
+func NewNameSystem(r routing.ValueStore, ds ds.Datastore, rslv madns.BasicResolver, cachesize int) NameSystem {
 	var (
 		cache     *lru.Cache
 		staticMap map[string]path.Path
@@ -73,7 +74,7 @@ func NewNameSystem(r routing.ValueStore, ds ds.Datastore, cachesize int) NameSys
 	}
 
 	return &mpns{
-		dnsResolver:      NewDNSResolver(),
+		dnsResolver:      NewDNSResolver(rslv),
 		proquintResolver: new(ProquintResolver),
 		ipnsResolver:     NewIpnsResolver(r),
 		ipnsPublisher:    NewIpnsPublisher(r, ds),

namesys_test.go

@@ -17,6 +17,7 @@ import (
 	peer "github.com/libp2p/go-libp2p-core/peer"
 	pstoremem "github.com/libp2p/go-libp2p-peerstore/pstoremem"
 	record "github.com/libp2p/go-libp2p-record"
+	madns "github.com/multiformats/go-multiaddr-dns"
 )
 
 type mockResolver struct {
@@ -109,7 +110,7 @@ func TestPublishWithCache0(t *testing.T) {
 		"pk":   record.PublicKeyValidator{},
 	})
 
-	nsys := NewNameSystem(routing, dst, 0)
+	nsys := NewNameSystem(routing, dst, madns.DefaultResolver, 0)
 	// CID is arbitrary.
 	p, err := path.ParsePath("QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn")
 	if err != nil {
@@ -142,7 +143,7 @@ func TestPublishWithTTL(t *testing.T) {
 		"pk":   record.PublicKeyValidator{},
 	})
 
-	nsys := NewNameSystem(routing, dst, 128)
+	nsys := NewNameSystem(routing, dst, madns.DefaultResolver, 128)
 	// CID is arbitrary.
 	p, err := path.ParsePath("QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn")
 	if err != nil {

republisher/repub_test.go

@@ -22,6 +22,8 @@ import (
 	ipns_pb "github.com/ipfs/go-ipns/pb"
 	path "github.com/ipfs/go-path"
 
+	madns "github.com/multiformats/go-multiaddr-dns"
+
 	keystore "github.com/ipfs/go-ipfs-keystore"
 	namesys "github.com/ipfs/go-namesys"
 	. "github.com/ipfs/go-namesys/republisher"
@@ -74,7 +76,7 @@ func TestRepublish(t *testing.T) {
 	var nodes []*mockNode
 	for i := 0; i < 10; i++ {
 		n := getMockNode(t, ctx)
-		ns := namesys.NewNameSystem(n.dht, n.store, 0)
+		ns := namesys.NewNameSystem(n.dht, n.store, madns.DefaultResolver, 0)
 
 		nsystems = append(nsystems, ns)
 		nodes = append(nodes, n)
@@ -153,7 +155,7 @@ func TestLongEOLRepublish(t *testing.T) {
 	var nodes []*mockNode
 	for i := 0; i < 10; i++ {
 		n := getMockNode(t, ctx)
-		ns := namesys.NewNameSystem(n.dht, n.store, 0)
+		ns := namesys.NewNameSystem(n.dht, n.store, madns.DefaultResolver, 0)
 
 		nsystems = append(nsystems, ns)
 		nodes = append(nodes, n)