Print out the goroutine id (#3433)

The TXT logger prints out the actual go routine ID

This feature depends on 'loggoroutine' build tag

```go build -tags loggoroutine```

formatter/txt/format.go

@@ -0,0 +1,31 @@
+//go:build !loggoroutine
+
+package txt
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/formatter/hook"
+)
+
+func (f *TextFormatter) Format(entry *logrus.Entry) ([]byte, error) {
+	var fields string
+	keys := make([]string, 0, len(entry.Data))
+	for k, v := range entry.Data {
+		if k == hook.EntryKeySource {
+			continue
+		}
+		keys = append(keys, fmt.Sprintf("%s: %v", k, v))
+	}
+
+	if len(keys) > 0 {
+		fields = fmt.Sprintf("[%s] ", strings.Join(keys, ", "))
+	}
+
+	level := f.parseLevel(entry.Level)
+
+	return []byte(fmt.Sprintf("%s %s %s%s: %s\n", entry.Time.Format(f.timestampFormat), level, fields, entry.Data[hook.EntryKeySource], entry.Message)), nil
+}

formatter/txt/format_gorutines.go

@@ -0,0 +1,35 @@
+//go:build loggoroutine
+
+package txt
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/formatter/hook"
+)
+
+func (f *TextFormatter) Format(entry *logrus.Entry) ([]byte, error) {
+	var fields string
+	keys := make([]string, 0, len(entry.Data))
+	for k, v := range entry.Data {
+		if k == hook.EntryKeySource {
+			continue
+		}
+
+		if k == hook.EntryKeyGoroutineID {
+			continue
+		}
+		keys = append(keys, fmt.Sprintf("%s: %v", k, v))
+	}
+
+	if len(keys) > 0 {
+		fields = fmt.Sprintf("[%s] ", strings.Join(keys, ", "))
+	}
+
+	level := f.parseLevel(entry.Level)
+
+	return []byte(fmt.Sprintf("%s %s %d %s%s: %s\n", entry.Time.Format(f.timestampFormat), level, entry.Data[hook.EntryKeyGoroutineID], fields, entry.Data[hook.EntryKeySource], entry.Message)), nil
+}

formatter/txt/formatter.go

@@ -0,0 +1,31 @@
+package txt
+
+import (
+	"time"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/formatter/levels"
+)
+
+// TextFormatter formats logs into text with included source code's path
+type TextFormatter struct {
+	timestampFormat string
+	levelDesc       []string
+}
+
+// NewTextFormatter create new MyTextFormatter instance
+func NewTextFormatter() *TextFormatter {
+	return &TextFormatter{
+		levelDesc:       levels.ValidLevelDesc,
+		timestampFormat: time.RFC3339, // or RFC3339
+	}
+}
+
+func (f *TextFormatter) parseLevel(level logrus.Level) string {
+	if len(f.levelDesc) < int(level) {
+		return ""
+	}
+
+	return f.levelDesc[level]
+}

formatter/txt/formatter_test.go

@@ -0,0 +1,26 @@
+package txt
+
+import (
+	"testing"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLogTextFormat(t *testing.T) {
+
+	someEntry := &logrus.Entry{
+		Data:    logrus.Fields{"att1": 1, "att2": 2, "source": "some/fancy/path.go:46"},
+		Time:    time.Date(2021, time.Month(2), 21, 1, 10, 30, 0, time.UTC),
+		Level:   3,
+		Message: "Some Message",
+	}
+
+	formatter := NewTextFormatter()
+	result, _ := formatter.Format(someEntry)
+
+	parsedString := string(result)
+	expectedString := "^2021-02-21T01:10:30Z WARN \\[(att1: 1, att2: 2|att2: 2, att1: 1)\\] some/fancy/path.go:46: Some Message\\s+$"
+	assert.Regexp(t, expectedString, parsedString)
+}