log: split out stackEnabled field, to not conflate features

log/format.go

@@ -33,8 +33,16 @@ var locationTrims = []string{
 // format output.
 func PrintOrigins(print bool) {
 	locationEnabled.Store(print)
+	if print {
+		stackEnabled.Store(true)
+	}
 }
 
+// storeStackRecords is an atomic flag controlling whether the log handler needs
+// to store the callsite stack. This is needed in case any handler wants to
+// print locations (locationEnabled), use vmodule, or print full stacks (BacktraceAt).
+var stackEnabled atomic.Bool
+
 // locationEnabled is an atomic flag controlling whether the terminal formatter
 // should append the log locations too when printing entries.
 var locationEnabled atomic.Bool

log/handler_glog.go

@@ -141,7 +141,7 @@ func (h *GlogHandler) Vmodule(ruleset string) error {
 	h.override.Store(len(filter) != 0)
 	// Enable location storage (globally)
 	if len(h.patterns) > 0 {
-		locationEnabled.Store(true)
+		stackEnabled.Store(true)
 	}
 	return nil
 }
@@ -176,7 +176,7 @@ func (h *GlogHandler) BacktraceAt(location string) error {
 	h.location = location
 	h.backtrace.Store(len(location) > 0)
 	// Enable location storage (globally)
-	locationEnabled.Store(true)
+	stackEnabled.Store(true)
 	return nil
 }
 

log/logger.go

@@ -189,7 +189,7 @@ func (l *logger) write(msg string, lvl Lvl, ctx []interface{}, skip int) {
 			Ctx:  ctxKey,
 		},
 	}
-	if locationEnabled.Load() {
+	if stackEnabled.Load() {
 		record.Call = stack.Caller(skip)
 	}
 	l.h.Log(record)

log/logger_test.go

@@ -28,7 +28,7 @@ func (n notimeHandler) Log(r *Record) error {
 // TestLoggingWithTrace checks that if BackTraceAt is set, then the
 // gloghandler is capable of spitting out a stacktrace
 func TestLoggingWithTrace(t *testing.T) {
-	defer locationEnabled.Store(locationEnabled.Load())
+	defer stackEnabled.Store(stackEnabled.Load())
 	out := new(bytes.Buffer)
 	logger := New()
 	{
@@ -41,10 +41,28 @@ func TestLoggingWithTrace(t *testing.T) {
 	}
 	logger.Trace("a message", "foo", "bar") // Will be bumped to INFO
 	have := out.String()
-	wantPrefix := `INFO [01-01|01:00:00.000|log/logger_test.go:59] a message
-        
-        goroutine`
-	if len(have) < len(wantPrefix) || strings.HasPrefix(have, wantPrefix) {
-		t.Errorf("\nhave: '%v'\nwant: '%v'\n", have, wantPrefix)
+	wantPrefix := "INFO [01-01|01:00:00.000] a message\n\ngoroutine"
+	if len(have) < len(wantPrefix) || !strings.HasPrefix(have, wantPrefix) {
+		t.Errorf("\nhave: %q\nwant: %q\n", have, wantPrefix)
+	}
+}
+
+// TestLoggingWithVmodule checks that vmodule works.
+func TestLoggingWithVmodule(t *testing.T) {
+	defer stackEnabled.Store(stackEnabled.Load())
+	out := new(bytes.Buffer)
+	logger := New()
+	{
+		glog := NewGlogHandler(StreamHandler(out, TerminalFormat(false)))
+		glog.Verbosity(LvlCrit)
+		logger.SetHandler(notimeHandler{glog})
+		logger.Warn("This should not be seen", "ignored", "true")
+		glog.Vmodule("logger_test.go=5")
+	}
+	logger.Trace("a message", "foo", "bar")
+	have := out.String()
+	want := "TRACE[01-01|01:00:00.000] a message                                foo=bar\n"
+	if have != want {
+		t.Errorf("\nhave: %q\nwant: %q\n", have, want)
 	}
 }