Merge pull request #282 from jjhuff/allow_empty_manifest_list

Allow empty lists when polling manifests via http

pkg/kubelet/kubelet.go

@@ -490,10 +490,7 @@ func (kl *Kubelet) extractFromHTTP(url string, updateChannel chan<- manifestUpda
 	// We're not sure if the person reading the logs is going to care about the single or
 	// multiple manifest unmarshalling attempt, so we need to put both in the logs, as is
 	// done at the end. Hence not returning early here.
-	if multiErr == nil && len(manifests) == 0 {
-		multiErr = fmt.Errorf("no elements in ContainerManifest array")
-	}
-	if multiErr == nil && manifests[0].Version == "" {
+	if multiErr == nil && len(manifests) > 0 && manifests[0].Version == "" {
 		multiErr = fmt.Errorf("got blank version field")
 	}
 	if multiErr == nil {

pkg/kubelet/kubelet_test.go

@@ -784,6 +784,42 @@ func TestExtractFromHttpMultiple(t *testing.T) {
 	}
 }
 
+func TestExtractFromHttpEmptyArray(t *testing.T) {
+	kubelet := Kubelet{}
+	updateChannel := make(chan manifestUpdate)
+	reader := startReading(updateChannel)
+
+	manifests := []api.ContainerManifest{}
+	data, err := json.Marshal(manifests)
+	if err != nil {
+		t.Fatalf("Some weird json problem: %v", err)
+	}
+
+	t.Logf("Serving: %v", string(data))
+
+	fakeHandler := util.FakeHandler{
+		StatusCode:   200,
+		ResponseBody: string(data),
+	}
+	testServer := httptest.NewServer(&fakeHandler)
+
+	err = kubelet.extractFromHTTP(testServer.URL, updateChannel)
+	if err != nil {
+		t.Errorf("Unexpected error: %#v", err)
+	}
+	close(updateChannel)
+
+	read := reader.GetList()
+
+	if len(read) != 1 {
+		t.Errorf("Unexpected list: %#v", read)
+		return
+	}
+	if len(read[0]) != 0 {
+		t.Errorf("Unexpected manifests: %#v", read[0])
+	}
+}
+
 func TestWatchEtcd(t *testing.T) {
 	watchChannel := make(chan *etcd.Response)
 	updateChannel := make(chan manifestUpdate)