retry

1 files changed, 15 insertions, 3 deletions

diff --git a/main.go b/main.go
index 37ebedc..d32fb01 100644
--- a/main.go
+++ b/main.go
@@ -12,6 +12,7 @@ import (
 	"net/smtp"
 	"net/textproto"
 	"strings"
+	"time"
 
 	"github.com/mhale/smtpd"
 	"github.com/pkg/errors"
@@ -85,9 +86,20 @@ func forward(targetEmail string, data []byte) error {
 	builder.WriteString("\r\n")
 	builder.Write(msgData)
 
-	err = smtp.SendMail(mxes[0].Host+":25", nil, `forwarder@localnet.cc`, []string{targetEmail}, builder.Bytes())
-	if err != nil {
-		return errors.Wrap(err, `failed targetEmail send mail via smtp`)
+	var retryCount = 5
+	for retryCount > 0 {
+		err = smtp.SendMail(mxes[0].Host+":25", nil, `forwarder@localnet.cc`, []string{targetEmail}, builder.Bytes())
+		if err, ok := err.(*textproto.Error); ok {
+			if 400 <= err.Code && err.Code < 500 {
+				log.Printf(`retry sleep 120s count=%v code=%v`, retryCount, err.Code)
+				time.Sleep(120 * time.Second)
+				retryCount--
+				continue
+			}
+		}
+		if err != nil {
+			return errors.Wrap(err, `failed targetEmail send mail via smtp`)
+		}
 	}
 	log.Printf("forwarded targetEmail=%v", targetEmail)