fix: helm GetTags cache writing (#23865)

Signed-off-by: Matthew Clarke <mclarke@spotify.com>
Co-authored-by: Linghao Su <linghao.su@daocloud.io>

util/helm/client.go

@@ -485,7 +485,11 @@ func (c *nativeHelmChart) GetTags(chart string, noCache bool) (*TagsList, error)
 		).Info("took to get tags")
 
 		if c.indexCache != nil {
-			if err := c.indexCache.SetHelmIndex(tagsURL, data); err != nil {
+			cacheData, err := json.Marshal(entries)
+			if err != nil {
+				return nil, fmt.Errorf("failed to encode tags: %w", err)
+			}
+			if err := c.indexCache.SetHelmIndex(tagsURL, cacheData); err != nil {
 				log.Warnf("Failed to store tags list cache for repo: %s: %v", tagsURL, err)
 			}
 		}

util/helm/client_test.go

@@ -373,3 +373,95 @@ func TestGetTagsFromURLEnvironmentAuthentication(t *testing.T) {
 		})
 	}
 }
+
+func TestGetTagsCaching(t *testing.T) {
+	requestCount := 0
+	server := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		requestCount++
+		t.Logf("request %d called %s", requestCount, r.URL.Path)
+
+		responseTags := fakeTagsList{
+			Tags: []string{
+				"1.0.0",
+				"1.1.0",
+				"2.0.0_beta",
+			},
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		require.NoError(t, json.NewEncoder(w).Encode(responseTags))
+	}))
+	t.Cleanup(server.Close)
+
+	serverURL, err := url.Parse(server.URL)
+	require.NoError(t, err)
+
+	t.Run("should cache tags correctly", func(t *testing.T) {
+		cache := &fakeIndexCache{}
+		client := NewClient(serverURL.Host, HelmCreds{
+			InsecureSkipVerify: true,
+		}, true, "", "", WithIndexCache(cache))
+
+		tags1, err := client.GetTags("mychart", false)
+		require.NoError(t, err)
+		assert.ElementsMatch(t, tags1, []string{
+			"1.0.0",
+			"1.1.0",
+			"2.0.0+beta",
+		})
+		assert.Equal(t, 1, requestCount)
+
+		requestCount = 0
+
+		tags2, err := client.GetTags("mychart", false)
+		require.NoError(t, err)
+		assert.ElementsMatch(t, tags2, []string{
+			"1.0.0",
+			"1.1.0",
+			"2.0.0+beta",
+		})
+		assert.Equal(t, 0, requestCount)
+
+		assert.NotEmpty(t, cache.data)
+
+		type entriesStruct struct {
+			Tags []string
+		}
+		var entries entriesStruct
+		err = json.Unmarshal(cache.data, &entries)
+		require.NoError(t, err)
+		assert.ElementsMatch(t, entries.Tags, []string{
+			"1.0.0",
+			"1.1.0",
+			"2.0.0+beta",
+		})
+	})
+
+	t.Run("should bypass cache when noCache is true", func(t *testing.T) {
+		cache := &fakeIndexCache{}
+		client := NewClient(serverURL.Host, HelmCreds{
+			InsecureSkipVerify: true,
+		}, true, "", "", WithIndexCache(cache))
+
+		requestCount = 0
+
+		tags1, err := client.GetTags("mychart", true)
+		require.NoError(t, err)
+		assert.ElementsMatch(t, tags1, []string{
+			"1.0.0",
+			"1.1.0",
+			"2.0.0+beta",
+		})
+		assert.Equal(t, 1, requestCount)
+
+		tags2, err := client.GetTags("mychart", true)
+		require.NoError(t, err)
+		assert.ElementsMatch(t, tags2, []string{
+			"1.0.0",
+			"1.1.0",
+			"2.0.0+beta",
+		})
+		assert.Equal(t, 2, requestCount)
+	})
+}