Make DHT bucket debug node ordering stable

Author: anacrolix

bucket.go

@@ -1,6 +1,8 @@
 package dht
 
 import (
+	"iter"
+	"maps"
 	"time"
 
 	"github.com/anacrolix/chansync"
@@ -19,8 +21,13 @@ func (b *bucket) Len() int {
 	return len(b.nodes)
 }
 
+func (b *bucket) NodeIter() iter.Seq[*node] {
+	return maps.Keys(b.nodes)
+}
+
+// Returns true if f returns true for all nodes. Iteration stops if f returns false.
 func (b *bucket) EachNode(f func(*node) bool) bool {
-	for n := range b.nodes {
+	for n := range b.NodeIter() {
 		if !f(n) {
 			return false
 		}

go.mod

@@ -1,6 +1,6 @@
 module github.com/anacrolix/dht/v2
 
-go 1.18
+go 1.23
 
 require (
 	filippo.io/edwards25519 v1.0.0-rc.1

go.sum

@@ -44,9 +44,11 @@ github.com/RoaringBitmap/roaring v0.4.23/go.mod h1:D0gp8kJQgE1A4LQ5wFLggQEyvDi06
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
 github.com/alecthomas/assert/v2 v2.0.0-alpha3 h1:pcHeMvQ3OMstAWgaeaXIAL8uzB9xMm2zlxt+/4ml8lk=
+github.com/alecthomas/assert/v2 v2.0.0-alpha3/go.mod h1:+zD0lmDXTeQj7TgDgCt0ePWxb0hMC1G+PGTsTCv1B9o=
 github.com/alecthomas/atomic v0.1.0-alpha2 h1:dqwXmax66gXvHhsOS4pGPZKqYOlTkapELkLb3MNdlH8=
 github.com/alecthomas/atomic v0.1.0-alpha2/go.mod h1:zD6QGEyw49HIq19caJDc2NMXAy8rNi9ROrxtMXATfyI=
 github.com/alecthomas/repr v0.0.0-20210801044451-80ca428c5142 h1:8Uy0oSf5co/NZXje7U1z8Mpep++QJOldL2hs/sBQf48=
+github.com/alecthomas/repr v0.0.0-20210801044451-80ca428c5142/go.mod h1:2kn6fqh/zIyPLmm3ugklbEi5hg5wS435eygvNfaDQL8=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
@@ -57,8 +59,6 @@ github.com/anacrolix/args v0.5.1-0.20220509024600-c3b77d0b61ac h1:XWoepbk3zgOQ8j
 github.com/anacrolix/args v0.5.1-0.20220509024600-c3b77d0b61ac/go.mod h1:Fj/N2PehEwTBE5t/V/9xgTcxDkuYQ+5IBoFw/8gkldI=
 github.com/anacrolix/backtrace v0.0.0-20221205112523-22a61db8f82e h1:A0Ty9UeyBDIo29ZMnk0AvPqWDIa4HVvCaJqWNlCrMXA=
 github.com/anacrolix/backtrace v0.0.0-20221205112523-22a61db8f82e/go.mod h1:4YFqy+788tLJWtin2jNliYVJi+8aDejG9zcu/2/pONw=
-github.com/anacrolix/bargle/v2 v2.0.0-20240804050250-9655b61917bc h1:+ZEZHmyNen2jUY2gD1YSDfmISIDLo+jKrOV3fZF7ZZw=
-github.com/anacrolix/bargle/v2 v2.0.0-20240804050250-9655b61917bc/go.mod h1:rKvwnOHgcXKPJTINj5RmkifgpxgEGC9bkJiv5kM4ctM=
 github.com/anacrolix/bargle/v2 v2.0.0-20240909020204-5265698a6040 h1:gneDM+Y60h9YY5xyG1buJss/OWjBZa+eYFO/Go3e7ro=
 github.com/anacrolix/bargle/v2 v2.0.0-20240909020204-5265698a6040/go.mod h1:rKvwnOHgcXKPJTINj5RmkifgpxgEGC9bkJiv5kM4ctM=
 github.com/anacrolix/chansync v0.3.0 h1:lRu9tbeuw3wl+PhMu/r+JJCRu5ArFXIluOgdF0ao6/U=
@@ -253,6 +253,7 @@ github.com/grpc-ecosystem/grpc-gateway/v2 v2.12.0/go.mod h1:ummNFgdgLhhX7aIiy35v
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
+github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/honeycombio/honeycomb-opentelemetry-go v0.3.0 h1:3qotL5cFNAiuLk/YZsUGNmz9ywnXqGP9hGFQoNo5PdA=
 github.com/honeycombio/honeycomb-opentelemetry-go v0.3.0/go.mod h1:qzzIv/RAGWhyRgyRwwRaxmn5tZMkc/bbTX3zit4sBGI=
 github.com/honeycombio/opentelemetry-go-contrib/launcher v0.0.0-20221031150637-a3c60ed98d54 h1:CFyJMKF0jR2dv+3Cpj/GuRa5XBXKnJqiqmWMYifTzok=
@@ -423,6 +424,7 @@ go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/atomic v1.10.0 h1:9qC72Qh0+3MqyJbAn8YU5xVq1frD8bn3JtD2oXtafVQ=
 go.uber.org/atomic v1.10.0/go.mod h1:LUxbIzbOniOlMKjJjyPfpl4v+PKK2cNJn91OQbhoJI0=
 go.uber.org/goleak v1.2.0 h1:xqgm/S+aQvhWFTtR0XK3Jvg7z8kGV8P4X14IzwN3Eqk=
+go.uber.org/goleak v1.2.0/go.mod h1:XJYK+MuIchqpmGmUSAzotztawfKvYLUIgg7guXrwVUo=
 go.uber.org/multierr v1.8.0 h1:dg6GjLku4EH+249NNmoIciG9N/jURbDG+pFlTkhzIC8=
 go.uber.org/multierr v1.8.0/go.mod h1:7EAYxJLBy9rStEaz58O2t4Uvip6FSURkq8/ppBp95ak=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=

server.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"net"
 	"runtime/pprof"
+	"slices"
 	"strings"
 	"text/tabwriter"
 	"time"
@@ -99,7 +100,11 @@ func (s *Server) WriteStatus(w io.Writer) {
 		if b.Len() > 0 {
 			tw := tabwriter.NewWriter(w, 0, 0, 1, ' ', 0)
 			fmt.Fprintf(tw, "  node id\taddr\tlast query\tlast response\trecv\tdiscard\tflags\n")
-			b.EachNode(func(n *node) bool {
+			// Bucket nodes ordered by distance from server ID.
+			nodes := slices.SortedFunc(b.NodeIter(), func(l *node, r *node) int {
+				return l.Id.Distance(s.id).Cmp(r.Id.Distance(s.id))
+			})
+			for _, n := range nodes {
 				var flags []string
 				if s.IsQuestionable(n) {
 					flags = append(flags, "q10e")
@@ -122,8 +127,7 @@ func (s *Server) WriteStatus(w io.Writer) {
 					n.failedLastQuestionablePing,
 					strings.Join(flags, ","),
 				)
-				return true
-			})
+			}
 			tw.Flush()
 		}
 	}