logger fixes and improvements (#1285)

* fix helper fields
* add metadata output for default logger

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

logger/default.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"sort"
 	"sync"
 	"time"
 
@@ -59,14 +60,24 @@ func (l *defaultLogger) Log(level Level, v ...interface{}) {
 		Message:   fmt.Sprint(v...),
 		Metadata:  make(map[string]string, len(fields)),
 	}
+
+	keys := make([]string, 0, len(fields))
 	for k, v := range fields {
+		keys = append(keys, k)
 		rec.Metadata[k] = fmt.Sprintf("%v", v)
 	}
 
+	sort.Strings(keys)
+	metadata := ""
+
+	for _, k := range keys {
+		metadata += fmt.Sprintf(" %s=%v", k, fields[k])
+	}
+
 	dlog.DefaultLog.Write(rec)
 
 	t := rec.Timestamp.Format("2006-01-02 15:04:05")
-	fmt.Printf("%s %v\n", t, rec.Message)
+	fmt.Printf("%s %s %v\n", t, metadata, rec.Message)
 }
 
 func (l *defaultLogger) Logf(level Level, format string, v ...interface{}) {
@@ -86,14 +97,24 @@ func (l *defaultLogger) Logf(level Level, format string, v ...interface{}) {
 		Message:   fmt.Sprintf(format, v...),
 		Metadata:  make(map[string]string, len(fields)),
 	}
+
+	keys := make([]string, 0, len(fields))
 	for k, v := range fields {
+		keys = append(keys, k)
 		rec.Metadata[k] = fmt.Sprintf("%v", v)
 	}
 
+	sort.Strings(keys)
+	metadata := ""
+
+	for _, k := range keys {
+		metadata += fmt.Sprintf(" %s=%v", k, fields[k])
+	}
+
 	dlog.DefaultLog.Write(rec)
 
 	t := rec.Timestamp.Format("2006-01-02 15:04:05")
-	fmt.Printf("%s %v\n", t, rec.Message)
+	fmt.Printf("%s %s %v\n", t, metadata, rec.Message)
 }
 
 func (n *defaultLogger) Options() Options {