Adds a few locks

logger.go

@@ -4,9 +4,13 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"sync"
 )
 
 type Logger struct {
+	// added to avoid concurrent writes
+	sync.Mutex
+
 	name     string
 	level    Level
 	backends []Backend
@@ -54,6 +58,9 @@ func (l *Logger) AsStdLog(level Level) *log.Logger {
 }
 
 func (l *Logger) Log(level Level, m string) {
+	l.Lock()
+	defer l.Unlock()
+
 	r := NewRecord(l.name, level, m)
 	for _, backend := range l.backends {
 		if r.Level >= backend.Level() {

logging.go

@@ -4,9 +4,13 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+	"sync"
 )
 
-var loggers map[string]*Logger
+var (
+	loggers map[string]*Logger
+	lock    sync.Mutex
+)
 
 type Level byte
 
@@ -38,6 +42,9 @@ func LevelByName(l string) (Level, error) {
 type Formatter func(*Record) string
 
 func GetLogger(name string) (l *Logger) {
+	lock.Lock()
+	defer lock.Unlock()
+
 	if name == "" {
 		name = "default"
 	}