allow to change output

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

zap.go

@@ -65,6 +65,14 @@ func (l *zaplog) Init(opts ...logger.Option) error {
 		return err
 	}
 
+	log = log.WithOptions(zap.WrapCore(func(c zapcore.Core) zapcore.Core {
+		return zapcore.NewCore(
+			zapcore.NewJSONEncoder(zapConfig.EncoderConfig),
+			zapcore.Lock(zapcore.AddSync(l.opts.Out)),
+			loggerToZapLevel(l.opts.Level),
+		)
+	}))
+
 	// Adding seed fields if exist
 	if l.opts.Fields != nil {
 		data := make([]zap.Field, 0, len(l.opts.Fields)/2)

zap_test.go

@@ -1,6 +1,7 @@
 package zap
 
 import (
+	"bytes"
 	"context"
 	"testing"
 
@@ -8,6 +9,18 @@ import (
 	"go.unistack.org/micro/v3/logger"
 )
 
+func TestOutput(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	l.Infof(context.TODO(), "test logger name: %s", "name")
+	if !bytes.Contains(buf.Bytes(), []byte(`test logger name`)) {
+		t.Fatalf("log not redirected: %s", buf.Bytes())
+	}
+}
+
 func TestName(t *testing.T) {
 	l := NewLogger()
 	if err := l.Init(); err != nil {