gotools/cmd/yamltool/merge.go

package main

import (
	"github.com/goccy/go-yaml"
	"github.com/spf13/cobra"
	"os"
	"reflect"
)

type MyMap yaml.MapSlice

func (m *MyMap) Set(key any, value any) {
	for i := range len(*m) {
		if (*m)[i].Key == key {
			(*m)[i].Value = value
			return
		}
	}
	*m = append(*m, yaml.MapItem{Key: key, Value: value})
}

func (m MyMap) Get(key any) any {
	for _, item := range m {
		if item.Key == key {
			return item.Value
		}
	}
	return nil
}

func mergeMap(yaml1 yaml.MapSlice, yaml2 yaml.MapSlice) yaml.MapSlice {
	res := MyMap(yaml1)

	for _, item := range yaml2 {
		initialValue := res.Get(item.Key)
		value := item.Value
		switch {
		case initialValue != nil:
			if reflect.TypeOf(initialValue) == reflect.TypeOf(yaml.MapSlice{}) &&
				reflect.TypeOf(value) == reflect.TypeOf(yaml.MapSlice{}) {
				mergedMap := mergeMap(initialValue.(yaml.MapSlice), value.(yaml.MapSlice))
				res.Set(item.Key, mergedMap)
			} else {
				res.Set(item.Key, item.Value)
			}
		default:
			res.Set(item.Key, item.Value)
		}
	}
	return yaml.MapSlice(res)
}

func merge(cmd *cobra.Command, args []string) error {
	res := make(yaml.MapSlice, 0)
	for _, arg := range args {
		config := parse(read(arg))
		res = mergeMap(res, config)
	}
	encode(os.Stdout, res)
	return nil
}