Move MergeMaps from helm-controller

https://github.com/fluxcd/helm-controller/blob/8492473195545b06a133ca42d353946a3bd60b67/internal/util/util.go#L29-L51

Signed-off-by: Dylan Arbour <arbourd@users.noreply.github.com>

runtime/transform/transform.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2020 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package transform
+
+// MergeMaps merges map b into given map a and returns the result.
+// It allows overwrites of map values with flat values, and vice versa.
+// This is copied from https://github.com/helm/helm/blob/v3.3.0/pkg/cli/values/options.go#L88,
+// as the public chartutil.CoalesceTables function does not allow
+// overwriting maps with flat values.
+func MergeMaps(a, b map[string]interface{}) map[string]interface{} {
+ out := make(map[string]interface{}, len(a))
+ for k, v := range a {
+ out[k] = v
+ }
+ for k, v := range b {
+ if v, ok := v.(map[string]interface{}); ok {
+ if bv, ok := out[k]; ok {
+ if bv, ok := bv.(map[string]interface{}); ok {
+ out[k] = MergeMaps(bv, v)
+ continue
+ }
+ }
+ }
+ out[k] = v
+ }
+ return out
+}

runtime/transform/transform_test.go

@@ -0,0 +1,77 @@
+/*
+Copyright 2020 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package transform
+
+import (
+ "reflect"
+ "testing"
+)
+
+func TestMergeMaps(t *testing.T) {
+ nestedMap := map[string]interface{}{
+ "foo": "bar",
+ "baz": map[string]string{
+ "cool": "stuff",
+ },
+ }
+ anotherNestedMap := map[string]interface{}{
+ "foo": "bar",
+ "baz": map[string]string{
+ "cool": "things",
+ "awesome": "stuff",
+ },
+ }
+ flatMap := map[string]interface{}{
+ "foo": "bar",
+ "baz": "stuff",
+ }
+ anotherFlatMap := map[string]interface{}{
+ "testing": "fun",
+ }
+
+ testMap := MergeMaps(flatMap, nestedMap)
+ equal := reflect.DeepEqual(testMap, nestedMap)
+ if !equal {
+ t.Errorf("Expected a nested map to overwrite a flat value. Expected: %v, got %v", nestedMap, testMap)
+ }
+
+ testMap = MergeMaps(nestedMap, flatMap)
+ equal = reflect.DeepEqual(testMap, flatMap)
+ if !equal {
+ t.Errorf("Expected a flat value to overwrite a map. Expected: %v, got %v", flatMap, testMap)
+ }
+
+ testMap = MergeMaps(nestedMap, anotherNestedMap)
+ equal = reflect.DeepEqual(testMap, anotherNestedMap)
+ if !equal {
+ t.Errorf("Expected a nested map to overwrite another nested map. Expected: %v, got %v", anotherNestedMap, testMap)
+ }
+
+ testMap = MergeMaps(anotherFlatMap, anotherNestedMap)
+ expectedMap := map[string]interface{}{
+ "testing": "fun",
+ "foo": "bar",
+ "baz": map[string]string{
+ "cool": "things",
+ "awesome": "stuff",
+ },
+ }
+ equal = reflect.DeepEqual(testMap, expectedMap)
+ if !equal {
+ t.Errorf("Expected a map with different keys to merge properly with another map. Expected: %v, got %v", expectedMap, testMap)
+ }
+}