tplimpl: Fix deadlock in getJSON

Fixes #3211

diff --git a/tpl/tplimpl/template_resources.go b/tpl/tplimpl/template_resources.go
index 48a79d0661349f6ec629dfd01c426ce23ba803e0..f10aa72e3cc22e9c65f9d87a58e077e18ada1085 100644 (file)
--- a/tpl/tplimpl/template_resources.go
+++ b/tpl/tplimpl/template_resources.go
@@ -36,6 +36,7 @@ var (
        remoteURLLock = &remoteLock{m: make(map[string]*sync.Mutex)}
        resSleep      = time.Second * 2 // if JSON decoding failed sleep for n seconds before retrying
        resRetries    = 1               // number of retries to load the JSON from URL or local file system
+       resCacheMu    sync.RWMutex
 )
 
 type remoteLock struct {
@@ -49,8 +50,8 @@ func (l *remoteLock) URLLock(url string) {
        if _, ok := l.m[url]; !ok {
                l.m[url] = &sync.Mutex{}
        }
-       l.m[url].Lock()
        l.Unlock()
+       l.m[url].Lock()
 }
 
 // URLUnlock unlocks an URL when the download has been finished. Use only in defer calls.
@@ -70,6 +71,9 @@ func getCacheFileID(cfg config.Provider, id string) string {
 // resGetCache returns the content for an ID from the file cache or an error
 // if the file is not found returns nil,nil
 func resGetCache(id string, fs afero.Fs, cfg config.Provider, ignoreCache bool) ([]byte, error) {
+       resCacheMu.RLock()
+       defer resCacheMu.RUnlock()
+
        if ignoreCache {
                return nil, nil
        }
@@ -88,6 +92,9 @@ func resGetCache(id string, fs afero.Fs, cfg config.Provider, ignoreCache bool)
 
 // resWriteCache writes bytes to an ID into the file cache
 func resWriteCache(id string, c []byte, fs afero.Fs, cfg config.Provider, ignoreCache bool) error {
+       resCacheMu.Lock()
+       defer resCacheMu.Unlock()
+
        if ignoreCache {
                return nil
        }

diff --git a/tpl/tplimpl/template_resources_test.go b/tpl/tplimpl/template_resources_test.go
index 8a9f62659013100a333a7c255ee27fc9b6f81b51..e7e7f77824901b66d68476b83ae20d6d50335e52 100644 (file)
--- a/tpl/tplimpl/template_resources_test.go
+++ b/tpl/tplimpl/template_resources_test.go
@@ -20,7 +20,9 @@ import (
        "net/http/httptest"
        "net/url"
        "strings"
+       "sync"
        "testing"
+       "time"
 
        "github.com/spf13/afero"
        "github.com/spf13/hugo/helpers"
@@ -173,6 +175,47 @@ func TestScpGetRemote(t *testing.T) {
        }
 }
 
+func TestScpGetRemoteParallel(t *testing.T) {
+       t.Parallel()
+       fs := new(afero.MemMapFs)
+       content := []byte(`T€st Content 123`)
+       url := "http://Foo.Bar/foo_Bar-Foo"
+       srv, cl := getTestServer(func(w http.ResponseWriter, r *http.Request) {
+               w.Write(content)
+       })
+       defer func() { srv.Close() }()
+
+       for _, ignoreCache := range []bool{false, true} {
+
+               cfg := viper.New()
+               cfg.Set("ignoreCache", ignoreCache)
+
+               var wg sync.WaitGroup
+
+               for i := 0; i < 50; i++ {
+                       wg.Add(1)
+                       go func(gor int) {
+                               defer wg.Done()
+                               for j := 0; j < 10; j++ {
+                                       c, err := resGetRemote(url, fs, cfg, cl)
+                                       if err != nil {
+                                               t.Errorf("Error getting resource content: %s", err)
+                                       }
+                                       if !bytes.Equal(c, content) {
+                                               t.Errorf("\nNet Expected: %s\nNet Actual: %s\n", string(content), string(c))
+                                       }
+
+                                       time.Sleep(23 * time.Millisecond)
+                               }
+                       }(i)
+               }
+
+               wg.Wait()
+       }
+
+       t.Log("Done!")
+}
+
 func TestParseCSV(t *testing.T) {
        t.Parallel()