feat: add a dht stat command

Currently, it just prints out the routing tables.

core/commands/dht.go

@@ -7,6 +7,8 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"regexp"
+	"text/tabwriter"
 	"time"
 
 	cmdenv "github.com/ipfs/go-ipfs/core/commands/cmdenv"
@@ -18,6 +20,9 @@ import (
 	path "github.com/ipfs/go-path"
 	peer "github.com/libp2p/go-libp2p-core/peer"
 	routing "github.com/libp2p/go-libp2p-core/routing"
+	dht "github.com/libp2p/go-libp2p-kad-dht"
+	kbucket "github.com/libp2p/go-libp2p-kbucket"
+	pstore "github.com/libp2p/go-libp2p-peerstore"
 	b58 "github.com/mr-tron/base58/base58"
 )
 
@@ -39,13 +44,183 @@ var DhtCmd = &cmds.Command{
 		"get":       getValueDhtCmd,
 		"put":       putValueDhtCmd,
 		"provide":   provideRefDhtCmd,
+		"stat":      statDhtCmd,
 	},
 }
 
 const (
 	dhtVerboseOptionName = "verbose"
 )
 
+type dhtPeerInfo struct {
+	ID            string
+	AgentVersion  string
+	LastUsefulAt  string
+	LastQueriedAt string
+}
+
+type dhtStat struct {
+	Name    string
+	Buckets []dhtBucket
+}
+
+type dhtBucket struct {
+	LastRefresh string
+	Peers       []dhtPeerInfo
+}
+
+var statDhtCmd = &cmds.Command{
+	Helptext: cmds.HelpText{
+		Tagline: "Returns stats about the DHTs",
+	},
+	Arguments: []cmds.Argument{
+		cmds.StringArg("dht", false, true, "The DHT whose table should be listed (wan or lan)."),
+	},
+	Options: []cmds.Option{},
+	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
+		nd, err := cmdenv.GetNode(env)
+		if err != nil {
+			return err
+		}
+
+		if !nd.IsOnline {
+			return ErrNotOnline
+		}
+
+		if nd.DHT == nil {
+			return fmt.Errorf("no DHT running")
+		}
+
+		id := kbucket.ConvertPeerID(nd.Identity)
+
+		dhts := make(map[string]*dht.IpfsDHT)
+		if len(req.Arguments) == 0 {
+			dhts["wan"] = nd.DHT.WAN
+			dhts["lan"] = nd.DHT.LAN
+		} else {
+			for _, arg := range req.Arguments {
+				switch arg {
+				case "wan":
+				case "lan":
+				default:
+					return cmds.Errorf(cmds.ErrClient, "unknown dht type: %s", arg)
+				}
+			}
+		}
+
+		for name, dht := range dhts {
+			rt := dht.RoutingTable()
+			lastRefresh := rt.GetTrackedCplsForRefresh()
+			infos := rt.GetPeerInfos()
+			buckets := make([]dhtBucket, 0, len(lastRefresh))
+			for _, pi := range infos {
+				cpl := kbucket.CommonPrefixLen(id, kbucket.ConvertPeerID(pi.Id))
+				if len(buckets) <= cpl {
+					buckets = append(buckets, make([]dhtBucket, 1+cpl-len(buckets))...)
+				}
+
+				info := dhtPeerInfo{ID: pi.Id.String()}
+
+				if ver, err := nd.Peerstore.Get(pi.Id, "AgentVersion"); err == nil {
+					info.AgentVersion, _ = ver.(string)
+				} else if err == pstore.ErrNotFound {
+					// ignore
+				} else {
+					// this is a bug, usually.
+					log.Errorw(
+						"failed to get agent version from peerstore",
+						"error", err,
+					)
+				}
+				if !pi.LastUsefulAt.IsZero() {
+					info.LastUsefulAt = pi.LastUsefulAt.Format(time.RFC3339)
+				}
+
+				if !pi.LastSuccessfulOutboundQueryAt.IsZero() {
+					info.LastQueriedAt = pi.LastSuccessfulOutboundQueryAt.Format(time.RFC3339)
+				}
+
+				buckets[cpl].Peers = append(buckets[cpl].Peers, info)
+			}
+			for i := 0; i < len(buckets) && i < len(lastRefresh); i++ {
+				refreshTime := lastRefresh[i]
+				if !refreshTime.IsZero() {
+					buckets[i].LastRefresh = refreshTime.Format(time.RFC3339)
+				}
+			}
+			res.Emit(dhtStat{
+				Name:    name,
+				Buckets: buckets,
+			})
+		}
+
+		return nil
+	},
+	Encoders: cmds.EncoderMap{
+		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, out dhtStat) error {
+			tw := tabwriter.NewWriter(w, 4, 4, 2, ' ', 0)
+			defer tw.Flush()
+
+			// Regex to remove fraction from duration.
+			re := regexp.MustCompile(`\.\d+`)
+
+			// Formats a time into XX ago and remove any decimal
+			// parts. That is, change "2m3.00010101s" to "2m3s ago".
+			now := time.Now()
+			since := func(t time.Time) string {
+				return string(re.ReplaceAll(
+					[]byte(now.Sub(t).String()),
+					nil,
+				)) + " ago"
+			}
+
+			count := 0
+			for _, bucket := range out.Buckets {
+				count += len(bucket.Peers)
+			}
+
+			fmt.Fprintf(tw, "DHT %s (%d peers):\n", out.Name, count)
+
+			for i, bucket := range out.Buckets {
+				lastRefresh := "never"
+				if bucket.LastRefresh != "" {
+					t, err := time.Parse(time.RFC3339, bucket.LastRefresh)
+					if err != nil {
+						return err
+					}
+					lastRefresh = since(t)
+				}
+				fmt.Fprintf(tw, "  Bucket %2d (%d peers) - refreshed %s:\n", i, len(bucket.Peers), lastRefresh)
+
+				for _, p := range bucket.Peers {
+					lastUseful := "never"
+					if p.LastUsefulAt != "" {
+						t, err := time.Parse(time.RFC3339, p.LastUsefulAt)
+						if err != nil {
+							return err
+						}
+						lastUseful = since(t)
+					}
+
+					lastQueried := "never"
+					if p.LastUsefulAt != "" {
+						t, err := time.Parse(time.RFC3339, p.LastQueriedAt)
+						if err != nil {
+							return err
+						}
+						lastQueried = since(t)
+					}
+
+					fmt.Fprintf(tw, "    %s\t useful %s,\t queried %s\t - %s\n", p.ID, lastUseful, lastQueried, p.AgentVersion)
+				}
+				fmt.Fprintln(tw)
+			}
+			return nil
+		}),
+	},
+	Type: dhtStat{},
+}
+
 var queryDhtCmd = &cmds.Command{
 	Helptext: cmds.HelpText{
 		Tagline:          "Find the closest Peer IDs to a given Peer ID by querying the DHT.",