feat: show tailnet peer diagnostics after coder ping (#12314)

Beginnings of a solution to #12297 Doesn't cover disco or definitively display whether we successfully connected to DERP, but shows some checklist diagnostics for connecting to an agent. For this first PR, I just added it to `coder ping` to see how we like it, but could be incorporated into `coder ssh` _et al._ after a timeout. ``` $ coder ping dogfood2 p2p connection established in 147ms pong from dogfood2 p2p via 95.217.xxx.yyy:42631 in 147ms pong from dogfood2 p2p via 95.217.xxx.yyy:42631 in 140ms pong from dogfood2 p2p via 95.217.xxx.yyy:42631 in 140ms ✔ preferred DERP region 999 (Council Bluffs, Iowa) ✔ sent local data to Coder networking coodinator ✔ received remote agent data from Coder networking coordinator preferred DERP 10013 (Europe Fly.io (Paris)) endpoints: 95.217.xxx.yyy:42631, 95.217.xxx.yyy:37576, 172.17.0.1:37576, 172.20.0.10:37576 ✔ Wireguard handshake 11s ago ```
2026-09-24 15:04:27 +08:00 · 2024-02-27 22:04:46 +04:00
parent 32691e67e6
commit 4e7beee102
11 changed files with 503 additions and 8 deletions
@@ -2,13 +2,17 @@ package cliui

 import (
 	"context"
+	"fmt"
 	"io"
+	"strconv"
+	"strings"
 	"time"

 	"github.com/google/uuid"
 	"golang.org/x/xerrors"

 	"github.com/coder/coder/v2/codersdk"
+	"github.com/coder/coder/v2/tailnet"
 )

 var errAgentShuttingDown = xerrors.New("agent is shutting down")
@@ -281,3 +285,55 @@ type closeFunc func() error
 func (c closeFunc) Close() error {
 	return c()
 }
+
+func PeerDiagnostics(w io.Writer, d tailnet.PeerDiagnostics) {
+	if d.PreferredDERP > 0 {
+		rn, ok := d.DERPRegionNames[d.PreferredDERP]
+		if !ok {
+			rn = "unknown"
+		}
+		_, _ = fmt.Fprintf(w, "✔ preferred DERP region: %d (%s)\n", d.PreferredDERP, rn)
+	} else {
+		_, _ = fmt.Fprint(w, "✘ not connected to DERP\n")
+	}
+	if d.SentNode {
+		_, _ = fmt.Fprint(w, "✔ sent local data to Coder networking coodinator\n")
+	} else {
+		_, _ = fmt.Fprint(w, "✘ have not sent local data to Coder networking coordinator\n")
+	}
+	if d.ReceivedNode != nil {
+		dp := d.ReceivedNode.DERP
+		dn := ""
+		// should be 127.3.3.40:N where N is the DERP region
+		ap := strings.Split(dp, ":")
+		if len(ap) == 2 {
+			dp = ap[1]
+			di, err := strconv.Atoi(dp)
+			if err == nil {
+				var ok bool
+				dn, ok = d.DERPRegionNames[di]
+				if ok {
+					dn = fmt.Sprintf("(%s)", dn)
+				} else {
+					dn = "(unknown)"
+				}
+			}
+		}
+		_, _ = fmt.Fprintf(w,
+			"✔ received remote agent data from Coder networking coordinator\n    preferred DERP region: %s %s\n    endpoints: %s\n",
+			dp, dn, strings.Join(d.ReceivedNode.Endpoints, ", "))
+	} else {
+		_, _ = fmt.Fprint(w, "✘ have not received remote agent data from Coder networking coordinator\n")
+	}
+	if !d.LastWireguardHandshake.IsZero() {
+		ago := time.Since(d.LastWireguardHandshake)
+		symbol := "✔"
+		// wireguard is supposed to refresh handshake on 5 minute intervals
+		if ago > 5*time.Minute {
+			symbol = "⚠"
+		}
+		_, _ = fmt.Fprintf(w, "%s Wireguard handshake %s ago\n", symbol, ago.Round(time.Second))
+	} else {
+		_, _ = fmt.Fprint(w, "✘ Wireguard is not connected\n")
+	}
+}
@@ -6,6 +6,7 @@ import (
 	"context"
 	"io"
 	"os"
+	"regexp"
 	"strings"
 	"sync/atomic"
 	"testing"
@@ -15,12 +16,14 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/xerrors"
+	"tailscale.com/tailcfg"

 	"github.com/coder/coder/v2/cli/clibase"
 	"github.com/coder/coder/v2/cli/clitest"
 	"github.com/coder/coder/v2/cli/cliui"
 	"github.com/coder/coder/v2/coderd/util/ptr"
 	"github.com/coder/coder/v2/codersdk"
+	"github.com/coder/coder/v2/tailnet"
 	"github.com/coder/coder/v2/testutil"
 )

@@ -476,3 +479,191 @@ func TestAgent(t *testing.T) {
 		require.NoError(t, cmd.Invoke().Run())
 	})
 }
+
+func TestPeerDiagnostics(t *testing.T) {
+	t.Parallel()
+	testCases := []struct {
+		name  string
+		diags tailnet.PeerDiagnostics
+		want  []*regexp.Regexp // must be ordered, can omit lines
+	}{
+		{
+			name: "noPreferredDERP",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        make(map[int]string),
+				SentNode:               true,
+				ReceivedNode:           &tailcfg.Node{DERP: "127.3.3.40:999"},
+				LastWireguardHandshake: time.Now(),
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile("^✘ not connected to DERP$"),
+			},
+		},
+		{
+			name: "preferredDERP",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP: 23,
+				DERPRegionNames: map[int]string{
+					23: "testo",
+				},
+				SentNode:               true,
+				ReceivedNode:           &tailcfg.Node{DERP: "127.3.3.40:999"},
+				LastWireguardHandshake: time.Now(),
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✔ preferred DERP region: 23 \(testo\)$`),
+			},
+		},
+		{
+			name: "sentNode",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               true,
+				ReceivedNode:           &tailcfg.Node{DERP: "127.3.3.40:999"},
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✔ sent local data to Coder networking coodinator$`),
+			},
+		},
+		{
+			name: "didntSendNode",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               false,
+				ReceivedNode:           &tailcfg.Node{DERP: "127.3.3.40:999"},
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✘ have not sent local data to Coder networking coordinator$`),
+			},
+		},
+		{
+			name: "receivedNodeDERPOKNoEndpoints",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{999: "Embedded"},
+				SentNode:               true,
+				ReceivedNode:           &tailcfg.Node{DERP: "127.3.3.40:999"},
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✔ received remote agent data from Coder networking coordinator$`),
+				regexp.MustCompile(`preferred DERP region: 999 \(Embedded\)$`),
+				regexp.MustCompile(`endpoints: $`),
+			},
+		},
+		{
+			name: "receivedNodeDERPUnknownNoEndpoints",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               true,
+				ReceivedNode:           &tailcfg.Node{DERP: "127.3.3.40:999"},
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✔ received remote agent data from Coder networking coordinator$`),
+				regexp.MustCompile(`preferred DERP region: 999 \(unknown\)$`),
+				regexp.MustCompile(`endpoints: $`),
+			},
+		},
+		{
+			name: "receivedNodeEndpointsNoDERP",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{999: "Embedded"},
+				SentNode:               true,
+				ReceivedNode:           &tailcfg.Node{Endpoints: []string{"99.88.77.66:4555", "33.22.11.0:3444"}},
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✔ received remote agent data from Coder networking coordinator$`),
+				regexp.MustCompile(`preferred DERP region:\s*$`),
+				regexp.MustCompile(`endpoints: 99\.88\.77\.66:4555, 33\.22\.11\.0:3444$`),
+			},
+		},
+		{
+			name: "didntReceiveNode",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               false,
+				ReceivedNode:           nil,
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✘ have not received remote agent data from Coder networking coordinator$`),
+			},
+		},
+		{
+			name: "noWireguardHandshake",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               false,
+				ReceivedNode:           nil,
+				LastWireguardHandshake: time.Time{},
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✘ Wireguard is not connected$`),
+			},
+		},
+		{
+			name: "wireguardHandshakeRecent",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               false,
+				ReceivedNode:           nil,
+				LastWireguardHandshake: time.Now().Add(-5 * time.Second),
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^✔ Wireguard handshake \d+s ago$`),
+			},
+		},
+		{
+			name: "wireguardHandshakeOld",
+			diags: tailnet.PeerDiagnostics{
+				PreferredDERP:          0,
+				DERPRegionNames:        map[int]string{},
+				SentNode:               false,
+				ReceivedNode:           nil,
+				LastWireguardHandshake: time.Now().Add(-450 * time.Second), // 7m30s
+			},
+			want: []*regexp.Regexp{
+				regexp.MustCompile(`^⚠ Wireguard handshake 7m\d+s ago$`),
+			},
+		},
+	}
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			r, w := io.Pipe()
+			go func() {
+				defer w.Close()
+				cliui.PeerDiagnostics(w, tc.diags)
+			}()
+			s := bufio.NewScanner(r)
+			i := 0
+			got := make([]string, 0)
+			for s.Scan() {
+				got = append(got, s.Text())
+				if i < len(tc.want) {
+					reg := tc.want[i]
+					if reg.Match(s.Bytes()) {
+						i++
+					}
+				}
+			}
+			if i < len(tc.want) {
+				t.Logf("failed to match regexp: %s\ngot:\n%s", tc.want[i].String(), strings.Join(got, "\n"))
+				t.FailNow()
+			}
+		})
+	}
+}