Merge pull request ipfs/go-namesys#10 from ipfs/feat/custom-resolver

make DNS resolver pluggable

This commit was moved from ipfs/go-namesys@2454122

Author: Stebalien

namesys/README.md

@@ -10,9 +10,9 @@
 
 Package namesys defines `Resolver` and `Publisher` interfaces for IPNS paths, that is, paths in the form of `/ipns/<name_to_be_resolved>`. A "resolved" IPNS path becomes an `/ipfs/<cid>` path.
 
-Traditionally, these paths would be in the form of `/ipns/peer_id`, which references an IPNS record in a distributed `ValueStore` (usually the IPFS DHT).
+Traditionally, these paths would be in the form of `/ipns/{libp2p-key}`, which references an IPNS record in a distributed `ValueStore` (usually the IPFS DHT).
 
-Additionally, the /ipns/ namespace can also be used with domain names that use DNSLink (/ipns/my.domain.example, see https://dnslink.io) and proquint strings.
+Additionally, the `/ipns/` namespace can also be used with domain names that use DNSLink (`/ipns/en.wikipedia-on-ipfs.org`, see https://docs.ipfs.io/concepts/dnslink/).
 
 The package provides implementations for all three resolvers.
 

namesys/dns.go

@@ -10,14 +10,11 @@ import (
 
 	path "github.com/ipfs/go-path"
 	opts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
-	isd "github.com/jbenet/go-is-domain"
+	dns "github.com/miekg/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)
+// LookupTXTFunc is a function that lookups TXT record values.
+type LookupTXTFunc func(ctx context.Context, name string) (txt []string, err error)
 
 // DNSResolver implements a Resolver on DNS domains
 type DNSResolver struct {
@@ -27,8 +24,8 @@ type DNSResolver struct {
 }
 
 // NewDNSResolver constructs a name resolver using DNS TXT records.
-func NewDNSResolver() *DNSResolver {
-	return &DNSResolver{lookupTXT: net.LookupTXT}
+func NewDNSResolver(lookup LookupTXTFunc) *DNSResolver {
+	return &DNSResolver{lookupTXT: lookup}
 }
 
 // Resolve implements Resolver.
@@ -55,7 +52,7 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 	segments := strings.SplitN(name, "/", 2)
 	domain := segments[0]
 
-	if !isd.IsDomain(domain) {
+	if _, ok := dns.IsDomainName(domain); !ok {
 		out <- onceResult{err: fmt.Errorf("not a valid domain name: %s", domain)}
 		close(out)
 		return out
@@ -68,17 +65,11 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 		fqdn = domain + "."
 	}
 
-	if strings.HasSuffix(fqdn, "."+ethTLD+".") {
-		// This is an ENS name.  As we're resolving via an arbitrary DNS server
-		// that may not know about .eth we need to add our link domain suffix.
-		fqdn += linkTLD + "."
-	}
-
 	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 +130,10 @@ 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

namesys/dns_test.go

@@ -1,6 +1,7 @@
 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)
@@ -126,7 +127,16 @@ func newMockDNS() *mockDNS {
 			"fqdn.example.com.": {
 				"dnslink=/ipfs/QmYvMB9yrsSf7RKBghkfwmHJkzJhW2ZgVwq3LxBXXPasFr",
 			},
-			"www.wealdtech.eth.domains.": {
+			"en.wikipedia-on-ipfs.org.": {
+				"dnslink=/ipfs/bafybeiaysi4s6lnjev27ln5icwm6tueaw2vdykrtjkwiphwekaywqhcjze",
+			},
+			"custom.non-icann.tldextravaganza.": {
+				"dnslink=/ipfs/bafybeieto6mcuvqlechv4iadoqvnffondeiwxc2bcfcewhvpsd2odvbmvm",
+			},
+			"singlednslabelshouldbeok.": {
+				"dnslink=/ipfs/bafybeih4a6ylafdki6ailjrdvmr7o4fbbeceeeuty4v3qyyouiz5koqlpi",
+			},
+			"www.wealdtech.eth.": {
 				"dnslink=/ipns/ipfs.example.com",
 			},
 		},
@@ -166,7 +176,10 @@ func TestDNSResolution(t *testing.T) {
 	testResolution(t, r, "double.example.com", opts.DefaultDepthLimit, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
 	testResolution(t, r, "conflict.example.com", opts.DefaultDepthLimit, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjE", nil)
 	testResolution(t, r, "fqdn.example.com.", opts.DefaultDepthLimit, "/ipfs/QmYvMB9yrsSf7RKBghkfwmHJkzJhW2ZgVwq3LxBXXPasFr", nil)
+	testResolution(t, r, "en.wikipedia-on-ipfs.org", 2, "/ipfs/bafybeiaysi4s6lnjev27ln5icwm6tueaw2vdykrtjkwiphwekaywqhcjze", nil)
+	testResolution(t, r, "custom.non-icann.tldextravaganza.", 2, "/ipfs/bafybeieto6mcuvqlechv4iadoqvnffondeiwxc2bcfcewhvpsd2odvbmvm", nil)
+	testResolution(t, r, "singlednslabelshouldbeok", 2, "/ipfs/bafybeih4a6ylafdki6ailjrdvmr7o4fbbeceeeuty4v3qyyouiz5koqlpi", nil)
 	testResolution(t, r, "www.wealdtech.eth", 1, "/ipns/ipfs.example.com", ErrResolveRecursion)
 	testResolution(t, r, "www.wealdtech.eth", 2, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
-	testResolution(t, r, "www.wealdtech.eth.domains", 2, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
+	testResolution(t, r, "www.wealdtech.eth", 2, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
 }

namesys/namesys.go

@@ -7,8 +7,7 @@
 // DHT).
 //
 // Additionally, the /ipns/ namespace can also be used with domain names that
-// use DNSLink (/ipns/my.domain.example, see https://dnslink.io) and proquint
-// strings.
+// use DNSLink (/ipns/<dnslink_name>, https://docs.ipfs.io/concepts/dnslink/)
 //
 // The package provides implementations for all three resolvers.
 package namesys
@@ -23,40 +22,73 @@ import (
 	lru "github.com/hashicorp/golang-lru"
 	cid "github.com/ipfs/go-cid"
 	ds "github.com/ipfs/go-datastore"
+	dssync "github.com/ipfs/go-datastore/sync"
 	path "github.com/ipfs/go-path"
 	opts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
-	isd "github.com/jbenet/go-is-domain"
 	ci "github.com/libp2p/go-libp2p-core/crypto"
 	peer "github.com/libp2p/go-libp2p-core/peer"
 	routing "github.com/libp2p/go-libp2p-core/routing"
+	dns "github.com/miekg/dns"
+	madns "github.com/multiformats/go-multiaddr-dns"
 )
 
 // mpns (a multi-protocol NameSystem) implements generic IPFS naming.
 //
 // Uses several Resolvers:
 // (a) IPFS routing naming: SFS-like PKI names.
 // (b) dns domains: resolves using links in DNS TXT records
-// (c) proquints: interprets string as the raw byte data.
 //
 // It can only publish to: (a) IPFS routing naming.
 //
 type mpns struct {
-	dnsResolver, proquintResolver, ipnsResolver resolver
-	ipnsPublisher                               Publisher
+	ds ds.Datastore
+
+	dnsResolver, ipnsResolver resolver
+	ipnsPublisher             Publisher
 
 	staticMap map[string]path.Path
 	cache     *lru.Cache
 }
 
-// NewNameSystem will construct the IPFS naming system based on Routing
-func NewNameSystem(r routing.ValueStore, ds ds.Datastore, cachesize int) NameSystem {
-	var (
-		cache     *lru.Cache
-		staticMap map[string]path.Path
-	)
-	if cachesize > 0 {
-		cache, _ = lru.New(cachesize)
+type Option func(*mpns) error
+
+// WithCache is an option that instructs the name system to use a (LRU) cache of the given size.
+func WithCache(size int) Option {
+	return func(ns *mpns) error {
+		if size <= 0 {
+			return fmt.Errorf("invalid cache size %d; must be > 0", size)
+		}
+
+		cache, err := lru.New(size)
+		if err != nil {
+			return err
+		}
+
+		ns.cache = cache
+		return nil
 	}
+}
+
+// WithDNSResolver is an option that supplies a custom DNS resolver to use instead of the system
+// default.
+func WithDNSResolver(rslv madns.BasicResolver) Option {
+	return func(ns *mpns) error {
+		ns.dnsResolver = NewDNSResolver(rslv.LookupTXT)
+		return nil
+	}
+}
+
+// WithDatastore is an option that supplies a datastore to use instead of an in-memory map datastore. The datastore is used to store published IPNS records and make them available for querying.
+func WithDatastore(ds ds.Datastore) Option {
+	return func(ns *mpns) error {
+		ns.ds = ds
+		return nil
+	}
+}
+
+// NewNameSystem will construct the IPFS naming system based on Routing
+func NewNameSystem(r routing.ValueStore, opts ...Option) (NameSystem, error) {
+	var staticMap map[string]path.Path
 
 	// Prewarm namesys cache with static records for deterministic tests and debugging.
 	// Useful for testing things like DNSLink without real DNS lookup.
@@ -72,14 +104,29 @@ func NewNameSystem(r routing.ValueStore, ds ds.Datastore, cachesize int) NameSys
 		}
 	}
 
-	return &mpns{
-		dnsResolver:      NewDNSResolver(),
-		proquintResolver: new(ProquintResolver),
-		ipnsResolver:     NewIpnsResolver(r),
-		ipnsPublisher:    NewIpnsPublisher(r, ds),
-		staticMap:        staticMap,
-		cache:            cache,
+	ns := &mpns{
+		staticMap: staticMap,
+	}
+
+	for _, opt := range opts {
+		err := opt(ns)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if ns.ds == nil {
+		ns.ds = dssync.MutexWrap(ds.NewMapDatastore())
 	}
+
+	if ns.dnsResolver == nil {
+		ns.dnsResolver = NewDNSResolver(madns.DefaultResolver.LookupTXT)
+	}
+
+	ns.ipnsResolver = NewIpnsResolver(r)
+	ns.ipnsPublisher = NewIpnsPublisher(r, ns.ds)
+
+	return ns, nil
 }
 
 // DefaultResolverCacheTTL defines max ttl of a record placed in namesys cache.
@@ -138,7 +185,6 @@ func (ns *mpns) resolveOnceAsync(ctx context.Context, name string, options opts.
 	// Resolver selection:
 	// 1. if it is a PeerID/CID/multihash resolve through "ipns".
 	// 2. if it is a domain name, resolve through "dns"
-	// 3. otherwise resolve through the "proquint" resolver
 
 	var res resolver
 	ipnsKey, err := peer.Decode(key)
@@ -175,10 +221,12 @@ func (ns *mpns) resolveOnceAsync(ctx context.Context, name string, options opts.
 
 	if err == nil {
 		res = ns.ipnsResolver
-	} else if isd.IsDomain(key) {
+	} else if _, ok := dns.IsDomainName(key); ok {
 		res = ns.dnsResolver
 	} else {
-		res = ns.proquintResolver
+		out <- onceResult{err: fmt.Errorf("invalid IPNS root: %q", key)}
+		close(out)
+		return out
 	}
 
 	resCh := res.resolveOnceAsync(ctx, key, options)

namesys/namesys_test.go

@@ -109,7 +109,11 @@ func TestPublishWithCache0(t *testing.T) {
 		"pk":   record.PublicKeyValidator{},
 	})
 
-	nsys := NewNameSystem(routing, dst, 0)
+	nsys, err := NewNameSystem(routing, WithDatastore(dst))
+	if err != nil {
+		t.Fatal(err)
+	}
+
 	// CID is arbitrary.
 	p, err := path.ParsePath("QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn")
 	if err != nil {
@@ -142,7 +146,11 @@ func TestPublishWithTTL(t *testing.T) {
 		"pk":   record.PublicKeyValidator{},
 	})
 
-	nsys := NewNameSystem(routing, dst, 128)
+	nsys, err := NewNameSystem(routing, WithDatastore(dst), WithCache(128))
+	if err != nil {
+		t.Fatal(err)
+	}
+
 	// CID is arbitrary.
 	p, err := path.ParsePath("QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn")
 	if err != nil {

namesys/proquint.go

@@ -74,7 +74,10 @@ 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, err := namesys.NewNameSystem(n.dht, namesys.WithDatastore(n.store))
+		if err != nil {
+			t.Fatal(err)
+		}
 
 		nsystems = append(nsystems, ns)
 		nodes = append(nodes, n)
@@ -153,7 +156,10 @@ 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, err := namesys.NewNameSystem(n.dht, namesys.WithDatastore(n.store))
+		if err != nil {
+			t.Fatal(err)
+		}
 
 		nsystems = append(nsystems, ns)
 		nodes = append(nodes, n)