tracer: display connections in an html table

timburks · timburks · commit 8d9ffffed1b0 · 2025-11-12T14:57:30.000-08:00
This reformats the connection list into an HTML table
and adds display of completed transactions (on the pool
of connections). Durations of completed transactions are
also displayed.

Here's an example (pasted as text):

Transactions (12)
RO	user identification		0s
RO	read ssh port			0s
RO	ssh get host key		0s
RO	xds make clusters		1ms
RO	serving: name resolution	0s
RO	xds make listeners		7ms
RO	telemetry operator info		1ms
RO	lookup nomad url		0s
RO	telemetry read identifier	0s
RO	lookup envoy admin address	0s
RO	ext_proc lookup serving api	0s
RW	traffic logging			0s
diff --git a/sqlstats/sqlstats.go b/sqlstats/sqlstats.go
@@ -77,16 +77,17 @@ type connStats struct {
 	why      string
 	at       time.Time
 	readOnly bool
+	done     bool
+	finished time.Time
 }
 
 func (t *Tracer) done(s *connStats) (why string, readOnly bool) {
 	s.mu.Lock()
 	why = s.why
 	readOnly = s.readOnly
 	at := s.at
-	s.why = ""
-	s.at = time.Time{}
-	s.readOnly = false
+	s.done = true
+	s.finished = time.Now()
 	s.mu.Unlock()
 
 	if t.TxTotalSeconds != nil {
@@ -233,6 +234,8 @@ func (t *Tracer) BeginTx(
 	s.why = why
 	s.at = time.Now()
 	s.readOnly = readOnly
+	s.done = false
+	s.finished = time.Time{}
 	s.mu.Unlock()
 
 	if t.TxCount != nil {
@@ -282,12 +285,16 @@ func (t *Tracer) Rollback(id sqliteh.TraceConnID, err error) {
 	}
 }
 
+type txSummary struct {
+	name     string
+	start    time.Time
+	readOnly bool
+	done     bool
+	finished time.Time
+}
+
 func (t *Tracer) HandleConns(w http.ResponseWriter, r *http.Request) {
-	type txSummary struct {
-		name     string
-		start    time.Time
-		readOnly bool
-	}
+
 	var summary []txSummary
 
 	t.curTxs.Range(func(k, v any) bool {
@@ -298,6 +305,8 @@ func (t *Tracer) HandleConns(w http.ResponseWriter, r *http.Request) {
 			name:     s.why,
 			start:    s.at,
 			readOnly: s.readOnly,
+			done:     s.done,
+			finished: s.finished,
 		})
 		s.mu.Unlock()
 
@@ -311,22 +320,36 @@ func (t *Tracer) HandleConns(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	w.WriteHeader(200)
 	fmt.Fprintf(w, "<!DOCTYPE html><html><title>sqlite conns</title><body>\n")
-	fmt.Fprintf(w, "<p>outstanding sqlite transactions: %d</p>\n", len(summary))
-	fmt.Fprintf(w, "<pre>\n")
+	fmt.Fprintf(w, "<h1>Transactions (%d)</h1>\n", len(summary))
+	fmt.Fprintf(w, "<table>\n")
 	for _, s := range summary {
-		rw := ""
+		rw := "RO"
 		if !s.readOnly {
-			rw = " read-write"
+			rw = "RW"
 		}
 		fmt.Fprintf(
 			w,
-			"\n\t%s (%v)%s",
-			html.EscapeString(s.name),
-			now.Sub(s.start).Round(time.Millisecond),
+			"\n\t<tr><td>%s</td><td>%s</td><td>%v</td></tr>",
 			rw,
+			emphasizeIfTrue(s.done, html.EscapeString(s.name)),
+			displayDuration(now, s),
 		)
 	}
-	fmt.Fprintf(w, "</pre></body></html>\n")
+	fmt.Fprintf(w, "</table></body></html>\n")
+}
+
+func emphasizeIfTrue(v bool, s string) string {
+	if v {
+		return "<i>" + s + "</i>"
+	}
+	return "<strong>" + s + "</strong>"
+}
+
+func displayDuration(now time.Time, s txSummary) time.Duration {
+	if s.done {
+		return s.finished.Sub(s.start).Round(time.Millisecond)
+	}
+	return now.Sub(s.start).Round(time.Millisecond)
 }
 
 func (t *Tracer) Handle(w http.ResponseWriter, r *http.Request) {
