implement dht findprovs and add error output to dht query

core/commands/dht.go

@@ -9,6 +9,7 @@ import (
 
 	cmds "github.com/jbenet/go-ipfs/commands"
 	notif "github.com/jbenet/go-ipfs/notifications"
+	peer "github.com/jbenet/go-ipfs/p2p/peer"
 	ipdht "github.com/jbenet/go-ipfs/routing/dht"
 	u "github.com/jbenet/go-ipfs/util"
 )
@@ -21,6 +22,7 @@ var DhtCmd = &cmds.Command{
 
 	Subcommands: map[string]*cmds.Command{
 		"query":     queryDhtCmd,
+		"findprovs": findProvidersDhtCmd,
 	},
 }
 
@@ -97,6 +99,10 @@ var queryDhtCmd = &cmds.Command{
 					fmt.Fprintln(buf)
 				case notif.SendingQuery:
 					fmt.Fprintf(buf, "* querying %s\n", obj.ID)
+				case notif.QueryError:
+					fmt.Fprintf(buf, "error: %s\n", obj.Extra)
+				default:
+					fmt.Fprintf(buf, "unrecognized event type: %d\n", obj.Type)
 				}
 				return buf, nil
 			}
@@ -109,3 +115,78 @@ var queryDhtCmd = &cmds.Command{
 	},
 	Type: notif.QueryEvent{},
 }
+
+var findProvidersDhtCmd = &cmds.Command{
+	Helptext: cmds.HelpText{
+		Tagline: "Run a 'FindProviders' query through the DHT",
+		ShortDescription: `
+FindProviders will return a list of peers who are able to provide the value requested.
+`,
+	},
+
+	Arguments: []cmds.Argument{
+		cmds.StringArg("key", true, true, "The key to find providers for"),
+	},
+	Options: []cmds.Option{
+		cmds.BoolOption("verbose", "v", "Write extra information"),
+	},
+	Run: func(req cmds.Request) (interface{}, error) {
+		n, err := req.Context().GetNode()
+		if err != nil {
+			return nil, err
+		}
+
+		dht, ok := n.Routing.(*ipdht.IpfsDHT)
+		if !ok {
+			return nil, errors.New("Routing service was not a dht")
+		}
+
+		numProviders := 20
+
+		outChan := make(chan interface{})
+		pchan := dht.FindProvidersAsync(req.Context().Context, u.B58KeyDecode(req.Arguments()[0]), numProviders)
+
+		go func() {
+			defer close(outChan)
+			for p := range pchan {
+				np := p
+				outChan <- &np
+			}
+		}()
+		return outChan, nil
+	},
+	Marshalers: cmds.MarshalerMap{
+		cmds.Text: func(res cmds.Response) (io.Reader, error) {
+			outChan, ok := res.Output().(<-chan interface{})
+			if !ok {
+				return nil, u.ErrCast()
+			}
+
+			marshal := func(v interface{}) (io.Reader, error) {
+				obj, ok := v.(*peer.PeerInfo)
+				if !ok {
+					return nil, u.ErrCast()
+				}
+
+				verbose, _, err := res.Request().Option("v").Bool()
+				if err != nil {
+					return nil, err
+				}
+
+				buf := new(bytes.Buffer)
+				if verbose {
+					fmt.Fprintf(buf, "%s\n", obj.ID.Pretty())
+				} else {
+					fmt.Fprintf(buf, "%s\n", obj.ID)
+				}
+				return buf, nil
+			}
+
+			return &cmds.ChannelMarshaler{
+				Channel:   outChan,
+				Marshaler: marshal,
+			}, nil
+		},
+	},
+	Type: peer.PeerInfo{},
+}

notifications/query.go

@@ -15,12 +15,14 @@ const (
 	SendingQuery QueryEventType = iota
 	PeerResponse
 	FinalPeer
+	QueryError
 )
 
 type QueryEvent struct {
 	ID        peer.ID
 	Type      QueryEventType
 	Responses []*peer.PeerInfo
+	Extra     string
 }
 
 func RegisterForQueryEvents(ctx context.Context, ch chan<- *QueryEvent) context.Context {
@@ -49,6 +51,7 @@ func (qe *QueryEvent) MarshalJSON() ([]byte, error) {
 	out["ID"] = peer.IDB58Encode(qe.ID)
 	out["Type"] = int(qe.Type)
 	out["Responses"] = qe.Responses
+	out["Extra"] = qe.Extra
 	return json.Marshal(out)
 }
 
@@ -57,17 +60,21 @@ func (qe *QueryEvent) UnmarshalJSON(b []byte) error {
 		ID        string
 		Type      int
 		Responses []*peer.PeerInfo
+		Extra     string
 	}{}
 	err := json.Unmarshal(b, &temp)
 	if err != nil {
 		return err
 	}
+	if len(temp.ID) > 0 {
 		pid, err := peer.IDB58Decode(temp.ID)
 		if err != nil {
 			return err
 		}
 		qe.ID = pid
+	}
 	qe.Type = QueryEventType(temp.Type)
 	qe.Responses = temp.Responses
+	qe.Extra = temp.Extra
 	return nil
 }

routing/dht/lookup.go

@@ -67,7 +67,6 @@ func (dht *IpfsDHT) GetClosestPeers(ctx context.Context, key u.Key) (<-chan peer
 				filtered = append(filtered, dht.peerstore.PeerInfo(clp))
 			}
 		}
-		log.Errorf("filtered: %v", filtered)
 
 		// For DHT query command
 		notif.PublishQueryEvent(ctx, &notif.QueryEvent{

routing/dht/query.go

@@ -3,6 +3,7 @@ package dht
 import (
 	"sync"
 
+	notif "github.com/jbenet/go-ipfs/notifications"
 	peer "github.com/jbenet/go-ipfs/p2p/peer"
 	queue "github.com/jbenet/go-ipfs/p2p/peer/queue"
 	"github.com/jbenet/go-ipfs/routing"
@@ -230,6 +231,12 @@ func (r *dhtQueryRunner) queryPeer(cg ctxgroup.ContextGroup, p peer.ID) {
 		pi := peer.PeerInfo{ID: p}
 		if err := r.query.dht.host.Connect(cg.Context(), pi); err != nil {
 			log.Debugf("Error connecting: %s", err)
+
+			notif.PublishQueryEvent(cg.Context(), &notif.QueryEvent{
+				Type:  notif.QueryError,
+				Extra: err.Error(),
+			})
+
 			r.Lock()
 			r.errs = append(r.errs, err)
 			r.Unlock()