log: Fix DynamicLogHandler to also capture derived handlers (#9479)

op-service/log/dynamic.go

@@ -12,28 +12,42 @@ type LvlSetter interface {
 
 // DynamicLogHandler allow runtime-configuration of the log handler.
 type DynamicLogHandler struct {
-	slog.Handler // embedded, to expose any extra methods the underlying handler might provide
-	minLvl       slog.Level
+	h      slog.Handler
+	minLvl *slog.Level // shared with derived dynamic handlers
 }
 
 func NewDynamicLogHandler(lvl slog.Level, h slog.Handler) *DynamicLogHandler {
 	return &DynamicLogHandler{
-		Handler: h,
-		minLvl:  lvl,
+		h:      h,
+		minLvl: &lvl,
 	}
 }
 
 func (d *DynamicLogHandler) SetLogLevel(lvl slog.Level) {
-	d.minLvl = lvl
+	*d.minLvl = lvl
 }
 
 func (d *DynamicLogHandler) Handle(ctx context.Context, r slog.Record) error {
-	if r.Level < d.minLvl { // higher log level values are more critical
+	if r.Level < *d.minLvl { // higher log level values are more critical
 		return nil
 	}
-	return d.Handler.Handle(ctx, r) // process the log
+	return d.h.Handle(ctx, r) // process the log
 }
 
 func (d *DynamicLogHandler) Enabled(ctx context.Context, lvl slog.Level) bool {
-	return (lvl >= d.minLvl) && d.Handler.Enabled(ctx, lvl)
+	return (lvl >= *d.minLvl) && d.h.Enabled(ctx, lvl)
+}
+
+func (d *DynamicLogHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return &DynamicLogHandler{
+		h:      d.h.WithAttrs(attrs),
+		minLvl: d.minLvl,
+	}
+}
+
+func (d *DynamicLogHandler) WithGroup(name string) slog.Handler {
+	return &DynamicLogHandler{
+		h:      d.h.WithGroup(name),
+		minLvl: d.minLvl,
+	}
 }

op-service/log/dynamic_test.go

@@ -40,6 +40,33 @@ func TestDynamicLogHandler_SetLogLevel(t *testing.T) {
 	require.Equal(t, h.records[5].Message, "another error")
 }
 
+func TestDynamicLogHandler_WithAttrs(t *testing.T) {
+	h := new(testRecorder)
+	d := NewDynamicLogHandler(log.LevelInfo, h)
+	logger := log.NewLogger(d)
+	logwith := logger.With("a", 1) // derived logger
+
+	// increase log level
+	d.SetLogLevel(log.LevelDebug)
+
+	logwith.Info("info0")   // y
+	logwith.Debug("debug0") // y
+	logwith.Trace("trace0") // n
+
+	// and decrease log level
+	d.SetLogLevel(log.LevelWarn)
+
+	logwith.Info("info1")   // n
+	logwith.Warn("warn1")   // y
+	logwith.Error("error1") // y
+
+	require.Len(t, h.records, 2+2)
+	require.Equal(t, h.records[0].Message, "info0")
+	require.Equal(t, h.records[1].Message, "debug0")
+	require.Equal(t, h.records[2].Message, "warn1")
+	require.Equal(t, h.records[3].Message, "error1")
+}
+
 type testRecorder struct {
 	records []slog.Record
 }