invalid messageはretryしても完了しないので諦める refs #1

errors.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+
+	"golang.org/x/xerrors"
+)
+
+// ErrInvalidMessage is Messageが処理できない時に返す
+var ErrInvalidMessage = &Error{
+	Code:    "InvalidMessage",
+	Message: "InvalidMessage",
+	KV:      map[string]interface{}{},
+}
+
+// Error is Error情報を保持する struct
+type Error struct {
+	Code    string
+	Message string
+	KV      map[string]interface{}
+	err     error
+}
+
+// Error is error interface func
+func (e *Error) Error() string {
+	if e.KV == nil || len(e.KV) < 1 {
+		return fmt.Sprintf("%s: %s: %s", e.Code, e.Message, e.err)
+	}
+	return fmt.Sprintf("%s: %s: attribute:%+v :%s", e.Code, e.Message, e.KV, e.err)
+}
+
+// Is is err equal check
+func (e *Error) Is(target error) bool {
+	var appErr *Error
+	if !xerrors.As(target, &appErr) {
+		return false
+	}
+	return e.Code == appErr.Code
+}
+
+// Unwrap is return unwrap error
+func (e *Error) Unwrap() error {
+	return e.err
+}
+
+// newErrInvalidMessage is return ErrInvalidMessage
+func newErrInvalidMessage(message string, kv map[string]interface{}, err error) *Error {
+	return &Error{
+		Code:    ErrInvalidMessage.Code,
+		Message: message,
+		KV:      kv,
+		err:     err,
+	}
+}

gmail_notify_handler.go

@@ -6,6 +6,8 @@ import (
 	"io/ioutil"
 	"log"
 	"net/http"
+
+	"golang.org/x/xerrors"
 )
 
 // PubSubMessage is the payload of a Pub/Sub event.
@@ -48,7 +50,11 @@ func GmailNotifyPubSubHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	info, err := gmailService.GetErrorReportingInfo(ctx, d.EmailAddress, d.HistoryID, tbfErrorReportingLabelID)
-	if err != nil {
+	if xerrors.Is(err, ErrInvalidMessage) {
+		log.Printf("invalid gmail history: %+v, %v\n", d, err)
+		w.WriteHeader(http.StatusOK) // Retryしても完了しないので、諦めて終わる
+		return
+	} else if err != nil {
 		log.Printf("gmailService.GetErrorReportingInfo: %v\n", err)
 		http.Error(w, "InternalServerError", http.StatusInternalServerError)
 		return

gmail_service.go

@@ -54,10 +54,10 @@ func (s *GmailService) GetMessage(ctx context.Context, userID string, startHisto
 	}
 
 	if len(res.History) < 1 {
-		return nil, fmt.Errorf("invalid History List. %+v", res)
+		return nil, newErrInvalidMessage("invalid gmail.history.list", map[string]interface{}{"history": res}, nil)
 	}
 	if len(res.History[0].Messages) < 1 {
-		return nil, fmt.Errorf("invalid History Messages. %+v", res.History[0])
+		return nil, newErrInvalidMessage("invalid gmail.history.message", map[string]interface{}{"history.message": res.History[0]}, nil)
 	}
 
 	msg, err := s.gus.Messages.Get(userID, res.History[0].Messages[0].Id).Context(ctx).Do()
@@ -75,7 +75,7 @@ func (s *GmailService) GetErrorReportingInfo(ctx context.Context, userID string,
 	}
 
 	if len(msg.Payload.Parts) < 2 {
-		return nil, fmt.Errorf("invalid error reporting mail format.%+v", msg.Payload)
+		return nil, newErrInvalidMessage("invalid error reporting mail format", map[string]interface{}{"payload": msg.Payload}, nil)
 	}
 
 	var plainText []byte