[BIVS-2645] YML merge (#970)

* YAML merge

* code cleanup

* extended tests & error messages

* reorganized for use with CLI service

* filename => path

* renamed YML tree Config to Contents

* replaced reflection with typw assertions

* concat is go 1.22

---------

Co-authored-by: Tamas Papik <[email protected]>

models/config_file_tree.go

@@ -0,0 +1,106 @@
+package models
+
+import (
+ "fmt"
+ "gopkg.in/yaml.v2"
+)
+
+func (ymlTree *ConfigFileTreeModel) Merge() (string, error) {
+ result, err := merge(ymlTree)
+ if err != nil {
+ return "", err
+ }
+
+ mergedYml, err := yaml.Marshal(result)
+ if err != nil {
+ return "", fmt.Errorf("failed to create YML result, error: %s", err)
+ }
+
+ return string(mergedYml), nil
+}
+
+type yamlMap = map[any]any
+
+func merge(ymlTree *ConfigFileTreeModel) (yamlMap, error) {
+ // Initial state is an empty map (YAML root)
+ initial := make(yamlMap)
+
+ result, err := mergeTree(initial, ymlTree)
+ if err != nil {
+ return nil, fmt.Errorf("failed to merge YML files, error: %s", err)
+ }
+
+ // Remove include list from result
+ delete(result, "include")
+
+ return result, nil
+}
+
+func mergeTree(existingValue yamlMap, treeToMerge *ConfigFileTreeModel) (yamlMap, error) {
+ var err error
+
+ // DFS: first the includes in the specified order, then the including file
+ for _, includedTree := range treeToMerge.Includes {
+ existingValue, err = mergeTree(existingValue, &includedTree)
+ if err != nil {
+ return nil, fmt.Errorf("failed to merge YML file %s, error: %s", includedTree.Path, err)
+ }
+ }
+
+ // We assume that each YML file has a map at root, it's invalid otherwise
+ var config yamlMap
+ err = yaml.Unmarshal([]byte(treeToMerge.Contents), &config)
+ if err != nil {
+ return nil, fmt.Errorf("failed to parse YML file %s, error: %s", treeToMerge.Path, err)
+ }
+
+ if config == nil {
+ // File is empty
+ config = make(yamlMap)
+ }
+
+ return mergeMap(existingValue, config), nil
+}
+
+func mergeValue(existingValue any, valueToMerge any) any {
+
+ switch valueToMerge.(type) {
+ case yamlMap:
+ existingMap, ok := existingValue.(yamlMap)
+ if !ok {
+ // Existing value is not a map, replace with new value
+ existingMap = make(yamlMap)
+ }
+ return mergeMap(existingMap, valueToMerge.(yamlMap))
+ case []any:
+ existingSlice, ok := existingValue.([]any)
+ if !ok {
+ // Existing value is not a slice, replace with new value
+ existingSlice = nil
+ }
+ return mergeSlice(existingSlice, valueToMerge.([]any))
+ default:
+ // Simple types
+ return valueToMerge
+ }
+}
+
+func mergeMap(existingMap yamlMap, mapToMerge yamlMap) yamlMap {
+ for key, valueToMerge := range mapToMerge {
+ existingValue, exists := existingMap[key]
+ if exists {
+ // Key exists in result and merged maps
+ existingMap[key] = mergeValue(existingValue, valueToMerge)
+ } else {
+ // Key doesn't exist in result yet
+ existingMap[key] = valueToMerge
+ }
+ }
+
+ return existingMap
+}
+
+func mergeSlice(existingArray []any, arrayToAppend []any) []any {
+ existingArray = append(existingArray, arrayToAppend...)
+ return existingArray
+}