store a runtime.Frame in Entry instead of the caller function name

entry.go

@@ -61,7 +61,7 @@ type Entry struct {
 	Level Level
 
 	// Calling method, with package name
-	Caller string
+	Caller *runtime.Frame
 
 	// Message passed to Trace, Debug, Info, Warn, Error, Fatal or Panic
 	Message string
@@ -144,10 +144,11 @@ func getPackageName(f string) string {
 }
 
 // getCaller retrieves the name of the first non-logrus calling function
-func getCaller() (method string) {
+func getCaller() *runtime.Frame {
 	// Restrict the lookback frames to avoid runaway lookups
 	pcs := make([]uintptr, maximumCallerDepth)
 	depth := runtime.Callers(minimumCallerDepth, pcs)
+	frames := runtime.CallersFrames(pcs[:depth])
 
 	// cache this package's fully-qualified name
 	callerInitOnce.Do(func() {
@@ -158,24 +159,23 @@ func getCaller() (method string) {
 		minimumCallerDepth = knownLogrusFrames
 	})
 
-	for i := 0; i < depth; i++ {
-		fullFuncName := runtime.FuncForPC(pcs[i]).Name()
-		pkg := getPackageName(fullFuncName)
+	for f, again := frames.Next(); again; f, again = frames.Next() {
+		pkg := getPackageName(f.Function)
 
 		// If the caller isn't part of this package, we're done
 		if pkg != logrusPackage {
-			return fullFuncName
+			return &f
 		}
 	}
 
 	// if we got here, we failed to find the caller's context
-	return ""
+	return nil
 }
 
 func (entry Entry) HasCaller() (has bool) {
 	return entry.Logger != nil &&
 		entry.Logger.ReportCaller &&
-		entry.Caller != ""
+		entry.Caller != nil
 }
 
 // This function is not declared with a pointer value because otherwise

json_formatter.go

@@ -82,7 +82,7 @@ func (f *JSONFormatter) Format(entry *Entry) ([]byte, error) {
 	data[f.FieldMap.resolve(FieldKeyMsg)] = entry.Message
 	data[f.FieldMap.resolve(FieldKeyLevel)] = entry.Level.String()
 	if entry.HasCaller() {
-		data[f.FieldMap.resolve(FieldKeyFunc)] = entry.Caller
+		data[f.FieldMap.resolve(FieldKeyFunc)] = entry.Caller.Function
 	}
 
 	var b *bytes.Buffer

json_formatter_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"runtime"
 	"strings"
 	"testing"
 )
@@ -167,8 +168,8 @@ func TestFieldsInNestedDictionary(t *testing.T) {
 	}
 
 	logEntry := WithFields(Fields{
-		"level":      "level",
-		"test":		  "test",
+		"level": "level",
+		"test":  "test",
 	})
 	logEntry.Level = InfoLevel
 
@@ -291,7 +292,7 @@ func TestFieldClashWithCaller(t *testing.T) {
 	SetReportCaller(true)
 	formatter := &JSONFormatter{}
 	e := WithField("func", "howdy pardner")
-	e.Caller = "somefunc"
+	e.Caller = &runtime.Frame{Function: "somefunc"}
 	b, err := formatter.Format(e)
 	if err != nil {
 		t.Fatal("Unable to format entry: ", err)

text_formatter.go

@@ -208,7 +208,7 @@ func (f *TextFormatter) printColored(b *bytes.Buffer, entry *Entry, keys []strin
 	caller := ""
 
 	if entry.HasCaller() {
-		caller = fmt.Sprintf(" %s()", entry.Caller)
+		caller = fmt.Sprintf(" %s()", entry.Caller.Function)
 	}
 
 	if f.DisableTimestamp {