From deac3be776851b0404aa2faa5c964d59845430a3 Mon Sep 17 00:00:00 2001
From: Florian Forster <ff@octo.it>
Date: Mon, 22 Jan 2018 08:34:51 +0100
Subject: [PATCH] Package app: Add mutex to persistingTokenSource.

---
 app/user.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/app/user.go b/app/user.go
index e47a5cc..1215653 100644
--- a/app/user.go
+++ b/app/user.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"sync"
 
 	"github.com/google/uuid"
 	legacy_context "golang.org/x/net/context"
@@ -107,9 +108,14 @@ type persistingTokenSource struct {
 	t   *oauth2.Token
 	src oauth2.TokenSource
 	key *datastore.Key
+
+	sync.Mutex
 }
 
 func (s *persistingTokenSource) Token() (*oauth2.Token, error) {
+	s.Lock()
+	defer s.Unlock()
+
 	tok, err := s.src.Token()
 	if err != nil {
 		return nil, err
-- 
2.11.0