Show ages on the AS and prefix pages in words (closes #163)

The Age column printed Go's duration format for every plural age, such
as "5m0s ago" or "360h0m0s ago".

The templates now register humanize.Time from go-humanize, which the
server already uses, as the timeSince function, and the hand-written
function is gone. Ages read "5 minutes ago", "3 hours ago" or "2 weeks
ago". An age under a minute reads "now" or in seconds instead of "just
now". An age over a month reads in months or years instead of a date.

Model: opus-5-5

TODO.md

@@ -33,6 +33,10 @@ tested.
 
 # Completed Steps
 
+- 2026-10-27: the Age column on the AS and prefix pages reads in words, such as
+  "5 minutes ago" or "2 weeks ago", instead of Go durations such as "360h0m0s
+  ago". An age under a minute reads in seconds, and one over a month in months
+  or years instead of a date (closes #163)
 - 2026-10-26: a write to a stored AS, peering or peer keeps the earlier of the
   two first-seen times and the later of the two last-seen times. An old update
   from a collector catching up on a backlog no longer moves last seen back

internal/server/handlers_internal_test.go

@@ -512,6 +512,71 @@ func TestPagesSayOriginZeroIsNoKnownOrigin(t *testing.T) {
 	}
 }
 
+// TestPagesShowAgesInWords stores routes last updated about 5 minutes, 3 hours
+// and 15 days ago, and checks that the AS page and the prefix pages show each
+// age in words. Before the fix the ages read "5m0s ago", "3h0m0s ago" and
+// "360h0m0s ago" (https://git.eeqj.de/sneak/routewatch/issues/163).
+func TestPagesShowAgesInWords(t *testing.T) {
+	t.Parallel()
+
+	db, err := database.New(&config.Config{StateDir: t.TempDir()}, logger.New())
+	if err != nil {
+		t.Fatalf("database.New: %v", err)
+	}
+
+	t.Cleanup(func() { _ = db.Close() })
+
+	// Each age is well past a whole number of its unit, so the time the test
+	// takes to run does not change the words.
+	ages := []struct {
+		prefix string
+		age    time.Duration
+		want   string
+	}{
+		{testPrefixV4, 5*time.Minute + 30*time.Second, "5 minutes ago"},
+		{"198.51.100.0/24", 3*time.Hour + 30*time.Minute, "3 hours ago"},
+		{"203.0.113.0/24", 15 * 24 * time.Hour, "2 weeks ago"},
+	}
+
+	now := time.Now().UTC()
+	routes := make([]*database.LiveRoute, 0, len(ages))
+
+	for _, a := range ages {
+		routes = append(routes, &database.LiveRoute{
+			Prefix: a.prefix, MaskLength: 24, IPVersion: 4,
+			OriginASN: 64500, PeerIP: testPeerV4, ASPath: []int{64500},
+			NextHop: testPeerV4, LastUpdated: now.Add(-a.age),
+		})
+	}
+
+	err = db.UpsertLiveRouteBatch(routes)
+	if err != nil {
+		t.Fatalf("UpsertLiveRouteBatch: %v", err)
+	}
+
+	s := New(db, streamer.New(logger.New(), metrics.New()), logger.New(), &config.Config{})
+
+	for _, a := range ages {
+		cell := `<td class="age">` + a.want + `</td>`
+
+		for _, path := range []string{asPagePath, "/prefix/" + a.prefix} {
+			rec := httptest.NewRecorder()
+			s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
+				t.Context(), http.MethodGet, path, nil))
+
+			if rec.Code != http.StatusOK {
+				t.Fatalf("%s: status %d, want %d; body %s",
+					path, rec.Code, http.StatusOK, rec.Body)
+			}
+
+			if !strings.Contains(rec.Body.String(), cell) {
+				t.Errorf("%s does not show the age of the route for %s as %q",
+					path, a.prefix, a.want)
+			}
+		}
+	}
+}
+
 // shortRequestDeadline is the deadline the tests below give a request. The
 // server's 30-second limit and the stats handlers' 4-second limit inherit it,
 // so the tests do not wait for either.

internal/templates/templates.go

@@ -7,9 +7,9 @@ import (
 	"net/url"
 	"strings"
 	"sync"
-	"time"
 
 	"git.eeqj.de/sneak/routewatch/internal/version"
+	"github.com/dustin/go-humanize"
 )
 
 //go:embed index.html
@@ -48,48 +48,7 @@ var (
 	once sync.Once
 )
 
-const (
-	hoursPerDay   = 24
-	daysPerMonth  = 30
-	cidrPartCount = 2 // A CIDR has two parts: prefix and length
-)
-
-// timeSince returns a human-readable duration since the given time
-func timeSince(t time.Time) string {
-	duration := time.Since(t)
-	if duration < time.Minute {
-		return "just now"
-	}
-
-	if duration < time.Hour {
-		minutes := int(duration.Minutes())
-		if minutes == 1 {
-			return "1 minute ago"
-		}
-
-		return duration.Truncate(time.Minute).String() + " ago"
-	}
-
-	if duration < hoursPerDay*time.Hour {
-		hours := int(duration.Hours())
-		if hours == 1 {
-			return "1 hour ago"
-		}
-
-		return duration.Truncate(time.Hour).String() + " ago"
-	}
-
-	days := int(duration.Hours() / hoursPerDay)
-	if days == 1 {
-		return "1 day ago"
-	}
-
-	if days < daysPerMonth {
-		return duration.Truncate(hoursPerDay*time.Hour).String() + " ago"
-	}
-
-	return t.Format("2006-01-02")
-}
+const cidrPartCount = 2 // A CIDR has two parts: prefix and length
 
 // prefixURL generates a URL path for a prefix in CIDR notation.
 // Takes a prefix like "192.168.1.0/24" and returns "/prefix/192.168.1.0/24"
@@ -113,7 +72,7 @@ func initTemplates() {
 
 	// Create common template functions
 	funcs := template.FuncMap{
-		"timeSince":       timeSince,
+		"timeSince":       humanize.Time,
 		"urlEncode":       url.QueryEscape,
 		"prefixURL":       prefixURL,
 		"appName":         func() string { return version.Name },